1B.Sc. (Calcutta University), M.Sc. (Jadavpur University
7 BSc (Indira Gandhi Open University) MSc(PUSHA) Asst Professor;Institute of Hotel management; Government of India; Chennai
Hello! Are We Alone? If You're Like Me, You May
Want to Know Me!Bhattacharya et. al.
Abstract
INTRODUCTION
Alien life forms are generally regarded
as the stuff of science fiction and fantasy and subject for/from the movies by
several times Oscar winner Hollywood director Steven Spielberg.But both SETI (Search for extra-terrestrial intelligence),(hile
philosophers and biologists may debate the meaning of the term 'intelligence',
for the purposes of the SETI project intelligence simply means the ability to
build large radio telescopes and transmitter of high-powered radio signals or
intense laser beams and NASA's Exobiology Program, which seeks to understand the
origin, evolution and distribution of life in the universe, researchers are
about to begin the SETI Microwave observing project Radio Telescopes around the
world which will search for signals produced by other intelligence. There are
of course two schools of thoughts about intelligent life out there in the galaxy
.It is argued that life on the planet earth, and especially intelligent life,
is the result of an incredibly unlikely set of circumstances; and there is no
intelligent life anywhere else in our milky way galaxy,perhaps none in the
entire universe. But according to the opposing school argument, there are so
many stars and planets in the galaxy that, provided there is even a small
chance of intelligence developing on any one planet (super earth) it must have
happened many times on many different planets. Nobody seems to take the middle
view, that life is restricted to just a few planets in our galaxy; either it
exists solely on earth, or there are many inhabited planets or super earths. If
the SETI project detects just one signal, the implication will be that we are
not alone, and that evolutionary biology is an inherent characteristic of
certain locations in the universe planets like earth[1]
Building
material for life according to these authors -: Astronomy
related
What are the requirements for
development of life (simple, complex or intelligent)in universeespecially in
our galaxy milky way star’s planets?First of all, let us(the authors), compose
a list of possible astronomy related requirements for development of life on
the planet earth or if evolved in other worlds of our galaxy the milky way.
Fig. 1:
2nd
Generation Stars with Heavy Elements
·
Large planetary family to absorb debris.
·
Iron core to generate magnetosphere.
·
Planet massive enough to retain its
atmosphere.
·
Collision with planetoids to create
voids in tectonic plates and large moon(Please see also at URL
LINK (http://www.spacedaily.com/news/life-01×1.html)).
Spectral Type
Stars: G, Late F, Early Ka Late F or Early K Type Star are also Candidates for Having
Life-Bearing Planets
Stable Intensity
of Star
·
Large moon to stabilize
rotation because without large moon the rotational axis of the planetwillbe
unstable
.
·
Plate tectonic activity
.
·
Water(ocean must be) by cometary’s
seeding
.
·
Recent nearby nova to
clear out interstellar dust.
·
Time between large impactors for life
Main Sequence Star
Please see LINK http://homepage.sunrise.ch/homepage/schatzer/Alpha-Centauri.html)
·
Adequate Age for Life to Evolve.
·
Orbit within ' the Habitable Zone'.
·
Avoid close orbit and
being tidally locked to star
·
Not within a dense star
cluster
·
Sudden, occasional
environmental/ecological changes to encourage evolution.
Planetary Worlds whose Mass is between
0.5 and 10 Earth Masses(the current theoretical
optimum size, gravity, etc. for which life’s development is
favorable due to the ability to hold atmospheres, plate tectonics, magnetic
fields, etc.): Too little mass and the planet won’t be able to keep its
atmosphere (and inevitably liquid water) for longer than a few billion years;
too much mass and odds are fairly good that it will retain hydrogen and helium,
thereby adding more mass to the planet that allows it to trap more H+ and He-
thus starting a cycle that transforms the planet into a gas giant
URL (http://www.astrobio.net/news/modules.php?op=modload&name=News&file=article&sid=436&mode=thread&order=0&thold=0)
Earth-Like' Conditions for Life
Oxygen to nitrogen ratio in
atmosphereThe oxygen to nitrogen ratio is determined by the presence of life
and is, as such, self-regulated by life oxygen to nitrogen ratio in atmosphere
.
1
If larger: advanced life
functions would proceed too quickly.
2
If smaller: advanced
life functions would proceed too slowly.
3
Radioactive methane gas
generated by volcanism or like nearly all methane in our own atmosphere is
produced by bacteria and other life.
4
Presence of volcanoes [2]
5
Commets Impact[2]
6
Methane and
water are very important to any carbon based life[2]
The
Frank Drake Equation forTechnological Civilization in the Milky Way Galaxy
Universe or our galaxy is possibly
teaming with life according these authors particularly in the G and K class
stars in the Galactic Habitable Zone(HZ) [2]. How many planets may be there in
that galactic habitable zone?More than 4000 [2]We consider that life itself is
fairly common throughout this galaxy.How can we estimate the number of
technological civilizations that might exist among the stars? While working as
a radio astronomer at the National Radio Astronomy Observatory in Green Bank,
West Virginia, Dr. Frank Drake (he was once the Chairman of the Board of the
SETI Institute) conceived an approach to bind the terms involved in estimating
the number of technological civilizations that may exist in our galaxy.
The Drake
Equation, as it has become known, was first
presented by Drake himself in 1961 and identifies specific factors thought to
play a role in the development of such civilizations[3]. Although there is no unique solution to this equation, it is
a generally accepted tool used by the scientific community to examine these
factors.
The equation is usually writtenas:
N=R*×fp×ne×fl×fi×fc×L
Where, N= The number of civilizations in the milky way galaxy
whose electromagnetic emissions are detectable, R* =The rate of formation of
stars suitable for the development of intelligent life,fp= The fraction of
those stars with planetary systems ne= The number of planets, per solar system,
with an environment suitable for lifefl= The fraction of suitable planets on
which life actually appears fi= The fraction of life bearing planets on which
intelligent life emerges fc= The fraction of civilizations that can develop a
technology that releases detectable signs of their existence into space, and L=
The length of time such civilizations release detectable signals into space.
Drake himself estimates the final number of communicating civilizations in the
galaxy to be about 10,000. As per Drake, wemay calculate, for example, 0.333333333
7,300,613.497 planets may be containing
any kind of life, intelligent or not.0.333333333 973415.1329 "Jurassic" worlds or any other whose most
intelligent species is sub-sentient.0.333333333 12.16768916 planets whose most intelligent species is within (but not
over) 5000 years of current Western World technological development i.e.
~12 worlds with 'planets whose most
intelligent species is within (where life evolved without artificial
intervention).So planets with
'advanced technical civilizations are quite rare, if we consider modern civilizations
not more than 5000 years old and if the average age of a civilization is a
million years, that increases the number of intelligent species civilizations to 2400. In 2001, for the first
time, the researchers estimated how many planets might lie in the
"habitable zone[2]" around stars, where water is liquid and
photosynthesis was possible. The results suggest that an inhabited earth-like
planet(Super earth) could be as little as a few hundred light years away[2]. So
it is obvious that within the limits of our existing technology, any practical
search for distant intelligent life must necessarily be a search for some
manifestation of a distant technology, . The National
Research Council of US has emphasized the relevance and importance of searching
for evidence of the electromagnetic signature of distant civilizations. The
late astronomer Professor Carl Sagan FRS, estimated that there might be a
million technological civilizations in our galaxy alone who are able to
communicate with us.Frank Drake offered the number 10,000. John Oro, a pioneering
comet researcher, calculated that the milky way is sprinkled with a hundred
civilizations. And finally there are also skeptics like Ben Zuckerman, an
astronomer at UCLA, who thinks we may as well be alone in this galaxy if not in
the universe. All the estimates are however highly speculative. The fact
remains that there is yet no conclusive evidence of any life beyond ourearth.
Simple Life or Complex
Life or Intelligent Life
Simple
life in some form microscopic may be more and more than complex life form or
intelligent life form that understands physics or mathematics and target of SETI
that may also does exist. Recent life forms have been also discovered that do
not need solar energy to survive. Bacteria can live on energy derived from
chemical reactions rather than photosynthesis[2]. And, higher life forms
survive by consuming the bacteria. So evolving to complex organisms is highly
possible. More complex life will certainly be rarer. If at all they exist we do
not believe that we will ever make contact with them. Think once about the
vastness of space and the age of the universe. The vast distance between stars
and galaxies makes it less likely that any other life will be found because it
takes too long to travel and combined with the increased rarity, it is
extremely unlikely we could just go to the "next star over" and find
complex life there.[4]. Finally, with the age of the
universe, other civilizations could have grown and died out long before life
even started to develop here. So what are the chances we could travel somewhere
within a reasonable distance?
PanspermiaTheory
in Cosmos
The
big yet unsolved question is “are we alone in this universe?” If and even
multiple universes are present,then is there also chance of development of life
in planet or phantasmal in those universe[5]? Paul Devis of Australian center
for astro-biology Macquire university retired the claim of astro-biologists that
life is cosmic in pattern bound to arise under earth like conditions and likely
to spread across the galaxies. He first raised question ‘are we alone in the cosmic eternity”. Or life also
existed in extraterrestrial planets or atmosphere or in asteroids where from it
came through a rocket system. Our heavenly (expired in 2006)mom late Mrs.Bani
Bhattacharya(1935 ,2006), of residence7/51 Purbapalli, PO- Sodepur, District-24
Parganas(North) Kol-110,West Bengal,India, used to tell our brothers and sister
in our child hood times in 1960s such kinds of peculiar stories. She had
auditory hallucination. She had a false belief of Panspermia theory, i.e., life
exists throughout cosmos. People from extraterrestrial of other galaxies, other
planets used to tell her various stories or used to speak with her. Really
civilized life also existed in
extraterrestrial planets or atmosphere or other universe? If it was so,
on the countless other planets that may circle other suns, in same distances
from their sun, as our earth circles our sun in a distance, life may exist. It
may exist as organic molecule like carbon molecule DNA or RNA based life, as
life on our earth (then there the evolutionary pattern would probably be same
as it happened in our earth we authors consider so) or they may be different.
Based on other molecule (let us say silica based, Iron based,sulphur based
DNA or RNA) with other types of evolutionary system and adaptation to their
environment. What we think about life is based on chains of carbon atoms with a
few atoms life phosphorus, sulphur and
nitrogen. One may speculate that one may have life with some other chemical
basis such as silicon, iron but carbon atoms should have most favorable
case(Life in the universe sated by Prof. S.W. Hawkings FRS).Francis Crick, the Nobel Laureate for
discovering the double helix structure of DNA molecule, once wrote ostensibly
to answer “Enrico Framis”,another Nobel
laureate for his famous question “…if there are intelligent beings in the
galaxy why are they only in earth?” and Crick assessed the hypothesis known as “Directed Panspermia hypothesis”,
that is to say a variant of Arrethenious 19th century theory modified, in that
Crick considered “whether life was deliberately planted in earth by some God?”
i.e. evolution from extraterrestrial space?.Answer that Francis Crick gave to
EnricoFramis “that life on earth could well have originated elsewhere
in the galaxy and that there had been time enough for intelligent beings to
evolve elsewhere. A suitable environment and to have dissipated prokaryotic and eukaryotic
microorganisms by rocket or asteroid to this planet where life may have
developed” Crick however admitted that the theory of “Directed Panspermia”
although suffered from possible paucity of evidences.
In
the great darkness of space time, between
stars there are condensed dark matter(composed of gas, dusts, organic
matter) and dark energy (we yet do not know composition of dark energy) with dozens of different kinds of organic
molecules. The abundance of these molecules further suggests that stuff of life
is everywhere in the cosmos. A very pertinent question raised by present authors mind
is “Is our universe especially designed to produce human race?” The possibility
of life is on some of thousands of planets in our milky way galaxy even or in
other galaxies of universe or may be in other universes if there are
multiple universes as per string theory[5].Life may have never arose
somewhere, on the other hand it may have arose and died and or never evolved
beyond the simplest form or in some planets there may be life which developed
more intelligent civilization, more advanced than human civilization on the
surface of earth. The biologists and physicists say that our planet “the earth”
is perfectly suitable one for evolution now. Moderate temperature,liquid water,
oxygen, nitrogen in air, greenhouse effect and so on were helpful for
development of life here. We the earthlings are supremely well adapted to this
environment, because we grew up here in three-dimensional form from
three-dimensional molecule very complex organic molecule DNA/RNA in three
dimensional space and one dimensional time on this earth.
In
the beginning of our universe, many say that there was the Big Bang, and only
physics, the mostly and yet undiscovered laws of universe. Then chemistry came
along at milder temperatures; when elementary particles quarks with its color
ultimately formed nucleons and then atoms; “Of course there was no carbon when
universe began 15 billion years ago. It was so hot that all the matters
were in form of quarks or Higgs particles and or zero rest mass Rupak particles and
then protons and neutrons came. However as the universe expanded it became
cool.After one minute of the Big Bang the temperature fell to billion degrees
at which temperature neutrons started to decay to protons. If this happened
then, all the matter in the universe ended up into simple matter hydrogen. Some
of the neutrons probably collided with protons and stuck together to form next
element Helium whose nucleus consist of two(2) neutrons and two(2) protons. But
no elements like carbon, oxygen, nitrogen, phosphorus, sulphur were there in
the early universe. The universe continued to expand and further cooled. Some
regions would have higher density than others. The gravitational attraction of
extra matter in those regions slowed down their expansion and eventually
stopped expansion. And they collapsed to form proto galaxies –-> galaxiesà
proto starsàstars starting
about two billion years from the Big Bang moment. From the stars planets were
formed. Our solar system was formed about ten billions years after the Big
Bang. The earth was formed largely out of the heavier elements including, hydrogen,
carbon, and oxygen[4]. These
united to give more and more complex organic molecules ever most complex largest
molecule on earth the RNA, DNA, enzymes, and genes epegenes which in turn
associated into organized aggregates and cell membranes, defining the most
primitive cells out of which life emerged in this planet.Chemistry and Biochemistry may be
then considered as the science of
matter and of its transformations, and life
in this planet is its highest form of expression of biochemistry.
Chemistry and notably supra-molecular chemistry thus entertained a double
relationship with biology of life in this planet.The progression from
elementary particles to the nucleus, the atom, the molecule, the super-molecule
RNA and the supra-molecular assembly of bio organic represents steps up the
ladder of supra-intelligence complexity
that happened here. Particles interacted to form atoms, atoms to form
molecules, molecules to form super molecules and supra-molecular assemblies,
etc. At each level a novel feature appeared that however did not exist at a
lower one. Thus a major line of development of chemistry to form life is
towards more and more complex systems and the emergence of complexity. The
highest level of complexity is expressed in the highest form of matter, living
matter, life, which itself culminated in the human brain, the plasticity of the
neural system, epigenesis, consciousness and thought. For this,
what took the active role, is the Darwinian evolution that might
also be brought into parallel with the recent development, via procedures of
both chemical synthesis and molecular biology, of molecular diversity methods that combined the generation of large
repertoires of molecules with highly efficient various selection procedures,
adaptations, and conflicts, to obtain products presenting specific properties.The
techniques of amplification by replication used in these methods would bear
relation to the spontaneous generation of the target superstructures by the
operation of self-processes.
A
further major development along these lines, concerns the design of molecular
species displaying the ability to form by self-replication.With respect to the frontiers of life itself, arises three
basic questions to these authors mind which may be today asked: How it appeared
in cosmos? Where are places it appeared? Why it appeared?
The
first concerns the origin of life on this planet, the earth only as
we know it, of our biological world. But is it true for only this planet? The
second considers the possibility of extraterrestrial life, within or beyond the
solar systems, beyond galaxies, or beyond even our universe. The third question
wonders why life has taken the forms we know; it has as corollary the question
whether other forms of life can (and do) exist: is there “artificial life”?; it
also implies that one might try to set the stage and implement the steps that
would allow, in a distant future, the creation of artificial forms of life.
Such an enterprise, which one cannot (and should not) at the present stage
outline in detail except for initial steps, rests on the presupposition that
there may be more than one, or several expressions of the processes
characterizing life. It thus invites to the exploration of the “frontiers of
other lifes”and of the chemical evolution of living worlds.
Questions
have been addressed about which one may speculate, let one’s imagination wander,
perhaps even set paths for future investigations. However, where the answers
lie is not clear at present, and future chemical research towards
ever more complex systems will uncover new modes of thinking and new ways of
acting that we at present do not know about and may even be unable to imagine.
What are the
Extraterrestrial Contributions for Life in this Planet?
An excess of L-amino acids was detected
in Murchison and Murray, two meteorites of the carbonaceous chondrite
class,although some discrepancies in the reported results remain to be yet
resolved. Cronin et al. originally discarded the evidence for small excesses
of L-enantiomers in Murchison as controversial and possibly caused by
terrestrial contamination[6].
Later, however,they themselves found an enantiomeric excess of various
amino acids that have never been reported, or are of limited occurrence,on
earth [7, 8].The detection of a
significant 15N enrichment in individual amino acid enantiomers from
Murchison, when was compared with their terrestrial counterparts, it confirmed
that the source of these amino acids was extraterrestrial and not any
terrestrial contamination.Carbonaceous chondrites were formed ~4.5 billion years
ago (i.e.,before the origin of life on Earth). There is still some
controversy regarding the actual origin of those meteoritic amino acids (i.e.,on
the meteorite parent body via Strecker synthesis in liquid water [3, 7] or in the interstellar medium
followed by incorporation into the parent body [6, 8]. Experiments with interstellar ice analogues have shown that
the UV-light–induced synthesis of amino acids was possible under the types of
conditions likely to be found in interstellar dust [9, 10]. No matter
which scenario is the correct one, the finding of an excess of L-aminoacids in
carbonaceous chondrites strongly suggests that the excess is of extraterrestrial
origin and existed in the solar system before the origin of life on earth.
The experiments further indicated that
at least some amino acids did not undergo complete racemization during their
residencein space, transit to earth, atmospheric entry, and surface impact.The
methyl amino acids found to exhibit considerable excessof the L-enantiomer in
the Murchison meteorite are reportedlyquite resistant to racemization [7].Racemization half-lives of
meteoritic -amino acids, the ones used for
protein synthesisin contemporary terrestrial organisms, were calculated
from models, taking into account the various environments that suchan amino acid
was exposed to, in space [11].In the temperature range between 150 and 300 K,
the racemization half-lives variedbetween amino acids by approximately 5-orders
of magnitude,with glutamic acid and iso-leucine predicted to retain an
enantiomericexcess much longer than phenylalanine, aspartic acid, and
alanine. These calculations suggested that the reported D/L value forglutamic
acid in Murchison of 0.3was close to the originalvalue [9], whereas that of
alanine (D/L=0.5) could correspondto original values in the range of 0.5 to 0.35
[11]. Note,however, that others
did not observe any enantiomeric excess in alanine [12]. Other experiments suggested that amino acid racemization at
high temperatures, as may be encountered duringatmospheric entry and surface
impacts of space bodies, wouldbe very rapid [13]. Incorporation into rocks of a
size to prevent their being heating all the way through should, however,
overcomethis problem.The presence of a variety of amino acids in meteorites
raisesthe further question of whether not only the source of enantiomericexcess
in terrestrial amino acids but also possibly the provenanceof pre-biotic amino
acids themselves was extraterrestrial. Meteoritesare actually considered
unlikely to have made a significant contribution to the total amount of pre-biotic
organics [14]. In contrast,
impacts of carbonaceous asteroids and comets during the period of heavy
bombardment 4.5–3.8 billionyears ago are thought to have been important sources
not justof amino acids but also a variety of prebiotic organic molecules[15, 16].Even greater amounts of
organic material are likelyto have been accreted from interplanetary dust
particles, which bare currently contributing ~3.2×105 kg.year-1
of intact organics.How large a portion of the total inventory of organics on
earlyearth came from extraterrestrial sources depends on a varietyof
factorsforemost among them is the actual composition of earth’searly atmosphere
and hence the extent of endogenous production [2].Whereas Miller and Urey
assumed a fully reducing early terrestrialatmosphere for their famous
experiments, it is now thought thatit was non-reducing or slightly reducing [16–18]. Theefficiency of organic
synthesis decreased rapidly as a functionof the H2/CO2
ratio. It has been calculated that with UV lightas the energy source, a yearly
production of 2×1011 kg organicswould have occurred
in a reducing atmosphere, whereas only 3×108 kgyear-1
would be produced in a neutral atmosphere (H2/CO2=0.1) [16]. Recent experiments suggested that
high-energyparticles, but not UV light, were able to generate amino
acidprecursors under mildly reducing conditions [14].The delivery to earth of large amounts of extraterrestrial
carbonaceouscompounds, including many of the building blocks of life,
mightactually fall under a new expanded definition of panspermia[19]. Originally, however, the term panspermiawas referred tothe transfer of some
form of viable extraterrestrial organism.Theoretically, the transfer of such
organisms between planetswithin our solar system is possible on rocks ejected
by largeimpacts [20]. A majority of these ejecta were heated to
temperaturesthat would kill all microbes; however, some remain almost un-shocked[21]. Further heating during the
ascent through the atmosphereof the home planet requires that the ejecta be of
a size thatprevents heating to 100°C all through, with a diameter of>0.2 m
estimated as necessary. Similar heating occurs duringthe entry into and passage
through the atmosphere of the targetplanet and the landing there. In between,
microbes would haveto survive thousands of years of travel through space.
Spaceis a very hostile environment in which UV and ionizing radiation,extreme
vacuum, andvery-very cold temperatures individually, andeven more so
in combination, are potentially lethal [14].
Theoreticaland experimental results indicate, however, that protectionfrom
these sterilizing factors however may be possible [14].The ability of some bacteria to form spores makes them
attractivecandidates for extraterrestrial organisms that might have
introducedlife to earth,explained
later in this article[22]. Spores represent a dormant state of any
bacteria. Thisoffers the advantage of the absence of (detectable) metabolism and
high resistance to a variety of physical insults, includingthose imposed by
prolonged space travel. Only a small proportion of spores were found to survive
space travel of up to 6 years(i.e., a minute fraction of the actual time
they may have tospend in space during transfer between planets [22].A single living organism may be
enough to seed life on another planet, however.Our Panspermia theories offer the
advantage of overcoming the difficulties arising from the shortness of the time
interval during which life on earth must have become established. Life could not
have arisen, or would have been destroyed if it did, during the heavy bombardment
period that ended about 3.8 Gyear ago. Micro fossils and stromatolites
indicate that complex life must have originated morethan 3.5 Gyr ago, and
evidence of biologically mediated carbon isotope fraction puts the existence of
life back even farther,to ~3.8 Gyr ago we do belief. Some biologists say
that life must have arisen around 10 billion years ago.This leaves a very
narrow window of time for the emergence of terrestrial life and adds some
plausibility to scenarios in which a preformed extraterrestrial life form started
life on earth as we authors think it so. Ultimately, however, postulating an
extraterrestrial origin not just for organic bio molecules but for entire
organisms simply shifts the location of the origin of life, without
addressing the underlying questions of how life arose and at what point during
this process homo chirality became established.Clearly the questions of life’s
origin and the relationship of its emergence to the phenomenon of homo-chirality
are the subject of active investigation. To conclude this review, we are struck
by the ‘‘symmetry’’ of some of the possible mechanisms linking these questions
and the expressions of these in aspects of biology. Homo-chirality, a
prerequisite of life’s emergence in some scientists’ view, might arise as a
consequence of the roles played by cosmology (e.g.,by cold dark matter and cold
dark energy) and occur at the far edge of galaxies. The conjunction of these
(the dark) with our increasing understanding of the processes that control
nuclear fusion and supernovas in providing both the building blocks and the
energy (the light) to drive life’s processes leads us to conclude with a quote
alluding to the symmetry of light and dark.Thus the darkness bears its fruit,
and proves itself.
Life
in Other Universes:- Possible with Symmetry
Breaking according to Us!
Though a big bang like event happened in
the early universe, universe spent a period of time in the early phase (~1 s
Plank’s time) in a super cooled stage. In the super cooled stage its density (3 K)
was then dominated by large positive constant vacuum energy and false vacuum.
The super cooled stage was then followed by appearance ofmultiple bubbles
inflation. The temperature variation occurred in 3 K
cosmological background imprinted some 10~35 sec in pre-inflationary
stage and grand unified theory (GUT) happened there with generation of trillions
and trillions degrees of temperature. As per old inflationary theory of Big
Bang, there appeared bubbles of true vacuum and inflation blowed up a small
casually connected region of the universe that was something much like the
observable universe of today within a bubble. This actually preceded
large scale cosmological homogeneity and were reduced to an exponentially small
number;
the present density of any magnetic monopoles, that according to many of
particle physicist, GUT, and would have been produced in
the pre-inflationary phase. In the old inflationary theory, the universe must
be homogeneous(and a little bit un-homogeneous too) in all its directions and
was isotropic. In old inflation theory, the super cooled stage was married by
appearance of bubbles of the true vacuum, the broken symmetry of ground state.
The model of old inflation theory however was later on abandoned, because
the exponential expansion of any super cooled state always present the bubbles
from merging and complicate the phase transition. Moreover in true sense,
universe is not totally homogenous, but in small scale,non-homogenous
too.
The cosmic inflation theories of Big
Bang postulate that our universe underwent a period of extremely rapid
expansion shortly after the Big Bang. But how the transition from inflation to
today’s more slowly expanding universe occurred has not yet cleared before the
world. It is also not known before world that why did inflation occur in the
first place and not happening now?The answer lies in that probably the universe
began in every possible ways we today can imagine and vast numbers of these
universes withered away. and universe did not have just one
unique beginning and history but a multitude of different ones.It is our authors multiverse concept which states
that“The present day universe would have begun as multiple bubbles in
the inflationary cosmos [5]. One of such bubbles is probably our universe. But
bubbles according to calculation were nothing but vacuum-matter- and energy,
would never have developed under such conditions”.
There happened an unusual phase
transition in mixture of helium isotopes. Normal fluid changes their phases
from gas to liquid to solid. Let us say, following a
bubble requires similar to the one that theorists believed ended inflation. But
the mixture of super fluid helium changed its properties in completely smooth
uniform fashion? Applied to cosmology, the super fluid transition allowed the
entire universe to gently roll from inflation to present day condition. Helium-3,
an isotope of helium with two protons and one neutron has thus a very unusual
property. Helium-3 can undergo the phenomenon of symmetry breaking.
Normally,
pairs of atoms in the liquid phase have and angular momentum aligned in a
random direction. But when cooled, the helium atoms would snap into a single
alignment, spontaneously creating order of chaos. The symmetry breaking in
early universe lead to creation of every force of universe,except gravity.
Kibbles hypothesis says that cooling of early universe as it expanded created
all massive structures. Defects called cosmic strings that were the seed of
large nets ofgalaxies we see around us today.String theory is controversial
because it has evolved over past 2½ decades, almost without references of
experiment or observation and many views that it is more on super high branches
of mathematics then reality of physics. Some versions of String theory however state possibility of electrical multi-universe.String
theory predicts the existence of an enormous number of different “vacuum
states,” or space time bubbles with different properties, such as physical
constants or particle masses. Of an infinite number of bubbles, there could be 10500different
varieties. And though any underlying basic law of physics would remain the
same, the bubbles could nonetheless exhibit vast physical diversity. Some of
the string theory postulate that our universe may sit on 3D membrane or Brane
suspended in a higher dimensional space, the way on a two dimensional sheet of
paper sits in 3-D words. Such a string theory explains the end of inflationary
period through collision of our Brane with another similar Brane inmulti-universe
concept.
Nowadays, the multi- universe concept is
a hot topic for discussionat real-world scientific conferences. The question
arises as to whether all these other universes are going to be like ours “or
whether they will have different laws and the laws in our universe are in some
sense special.String theory, a favorite candidate (although unsubstantiated by
experiment) for explaining all of physical laws of universe; suggests that the multi-universe
encompasses bubbles hosting various sorts of physics. String theory predicts
the existence of an enormous number of different “vacuum states,”,
or space time bubbles with different properties, such as physical constants or
particle masses. Of an infinite number of bubbles,there could be 10500different
varieties. And though any underlying basic law of physics would remain the
same, the bubbles could nonetheless exhibit vast physical diversity. Some of
those bubbles would not have lasted long enough for life, inflating but then
shrinking before any interesting chemistry commenced. Others would expand
forever, as seems the case with the bubble that humans occupy. In some, the
local laws of physics would have welcomed living things; others would have
permitted none of the particles and forces that conspire to build atoms,
molecules and metabolic mechanisms. It seems that universes come in all sizes
and flavors, with thebubble being the Goldilocks version, just right for life.
In other words, if the multiverse offers multiple bubbles that permit life to
evolve, humans would most likely live in an average bubble. If, for instance,
you throw out all the bubbles that would not allow life anyway, and then
calculate the average temperature of space in those that remain, humans should
measure a cosmic temperature that is not very far off from that average.
Somewhere in the cosmos, such a random mix of molecules has produced a brain
identical to yours in every respect, neurons in identical configurations, with
all your memories and perceptions.
Which
Stars in Our Galaxy Milky Way?
Stars in our Galaxy Milky way-
estimates: 500 billion (Royal Greenwich Observatory). And these stars include
everything from M-Class (Red Dwarfs) to Enormous O-Class stars (very hot, very
fast burning, Blue stars). Our ownstar sun is Class G star.K class stars are.The
cooler and “redder” the star, the longer it remains on the main sequence
(barring the obvious exception of red giants). The previously-mentioned O-Class
(very hot blue) stars will likely last only a few dozen million years, barely
enough time for star dust to coalesce into planets. Furthermore, hotter stars
emit enormous quantities of ionizing radiation (UV or higher). In fact, large
stars tend to emit the bulk of their radiation in the UV band. Stars in classes
B (a lower level blue-white) and A (white) suffer similarly, though not to the
extreme extent as O-class ones. Nevertheless, these stars will last only a few
billion years at most. This may be long enough for simple life and perhaps even
the simplest animal life to form, but not likely enough to allow
technologically advanced life to arise (unless its evolution is incredibly
quick). F-class (white) is likely to last from 4 to 6 billion years, certainly
enough to give rise to complex life (perhaps even intelligent life).
Unfortunately, in the earth-term timeline, at least, a white
sun will start to leave the main sequence just when intelligence does arise.
Timing truly is everything. So while it is certainly possible and even
plausible for a white sun to have a technically advanced civilization, we do
not find it particularly likely.
By contrast, the red dwarf (M-class)
stars will be around for billions of years, much more than enough time for life
to form. Furthermore, they do not emit as much ionizing radiation as even our
own sun (G-Class), another factor favoring a life-friendly environment. Unfortunately,
the cooler the star, the narrower is its life zone. We personally interpret
this fact to mean that a red star’s HZ will be less likely to contain a planet
of any sort, let alone one with other preconditions necessary for life to have
a chance on it. Even if the red sun’s HZ does have a planet with the
appropriate gravity, atmospheric and other characteristics, odds are fairly
high that the planet will suffer from “rotation lock” (one face always facing
the star). This means one side will be in eternal day or close to it (thus
rendering it too hot) and one side will be in eternal night (rendering it too
cold). However, there is still at least some chance other mitigating factors will
come to play on such a planet (the hot spot over the planet may create
atmospheric convection that creates winds, thus spreading heat more evenly over
the planet). Obviously, a rotationally-locked planet’s twilight zone could
offer a happy medium in which life, and even intelligence can flourish
in theory. However, as I will discuss later, such a planet will have a much
more difficult time developing a sustainable high technology civilization, and
even a high-end pre-industrial civilization. G (yellow), K (orange), and
low-level white stars areplaces favorable for advanced civilization to arise.
If we include all G and K stars, plus about 1/3 of all F stars, these stars are
about 22% of all stars in the galaxy (Wikipedia). If M-class (red) stars78% of
all stars permit HZ planets without a rotation lock, then perhaps another 10%
of all stars (the hotter M-class ones) can be added to (though I admit this
number is rather arbitrary). So we can say that as many as 33% of all stars
could support a technical civilization, given other necessary planetary
conditions listed above. Such stars that are the appropriate age .if you are
content with finding significant life in any form, you will likely find it
around planets between 2 and 5 billion years old. This is certainly long enough
for life to form an oxygen atmosphere (strong evidence of life), though not
necessarily sentient life. Hopefully, by 20162020 the Terrestrial Planet
Finder (TPF) project will finally give the answers we all want: where there
are rocky crust planets orbiting around G to K class stars within 200‑300 light
years of earth. The TPF mission will survey number of earth-sized planets in
habitable zone orbits in the galaxy.
How willYou Define Intelligent Life in
the Galaxy?[23]
According to these authors, intelligence
is a prerequisite fortechnology development. Intelligence drives technology
development.We say intelligent life is life with the ability to learn something
and share that knowledge with others. Then, the only thing oneneed is time to
build up a civilization, which will automatically lead to the ability to
produce radio waves or any other
thing that is needed to call a life form intelligent.
Any Special Signal Received yet by SETI
as a Proof of Intelligent Life?
In August 1977, an Ohio State University
radio telescope detected an unusual pulse of radiation from somewhere near the
constellation Sagittarius. The nearest star in that direction is 220 light
years away. The 37- seclong
signal was so startling that an astronomer monitoring the data scrawled
"Wow!" on the telescope's printout. The signal was within the band of
radio frequencies where transmissions are internationally banned on Earth[3]. In February 2003, astronomers
with the search for extraterrestrial intelligence (SETI) project, used a
massive telescope in Puerto Rico to re-examine 200 sections of the sky which
had all previously yielded unexplained radio signals. These signals had all
disappeared, except for one which had become strongercame from a spot between
the constellations Pisces andAries. SETI has many signal detectors type.
Recently in 2008, SETI signal detector called SonATA(SETI
on the ATA). Son ATA does everything that Prelude does, but it is a softwareonly
detector, capable of operating on commodity servers, without the
special-purpose hardware accelerators that had to be built into Prelude to make
it run in near-real time.On October 9, 2008 the X-band signal from the Rosetta
spacecraft was detected by the SonATA as a demsystem!
Fig. 2:X-Band
Signal from the Rosetta Spacecraft was Detectedby the SonATA as a
Figure 2
shows that detection. The Rosetta X-band signal is much stronger than the
signals fromVoyager Figure 2 [6]. After a half-century of scanning the
skies,SETI astronomers today have little to report. Why?. The problem could
be that SETI had been so long looking in the wrong place, at the wrong time,
and in the wrong way. "Why to waste time looking for old-style radio
signals? The advanced and intelligent aliens may use entangled particles
like neutrinos or some form of gravity waves to signal us.
Other
Technology to Detect ET Signals?
Neutrino
signaling has been studied bythe Kavli Institute of Theoretical Physics at the
University of California Santa Barbara, suggested that the more intelligentand
civilized aliens wouldrather opt for neutrino energies far above those
generated naturally by the sun and stars. Because there are very few energetic
neutrinos coming from any specific direction of space, a beam of high-energy
neutrinos that passed our way would be highly conspicuous. Contrast this with energetic
radio waves, which are generated by many compact astronomical sources; using
radio,intelligent ETs are in competition with the entire cosmos. Wesothink that
the intelligentaliens, if any, could use a
particle accelerator to collide and annihilate electrons and their
antiparticles (positrons) to make a narrow beam of neutrinos that can be aimed
at will.
In contrast to the classic SETI target, a continuous
narrow-band signal at a specific frequency, a beacon would
show up spread across a range of frequencies in the form of a short blip, or
perhaps a more attention-grabbing blip-blip. As it happens, many blips have
been recorded throughout the lifetime of SETI, but very little follow-up has
resulted, and for good reason. The procedure when a radio telescope picks up
something odd is to move the antenna off target, to make sure the signal fades
(thus eliminating equipment malfunction), and then move it back on target
again. If the signal is still there the second time, a partner radio telescope,
preferably far away, is brought into play to confirm that the source is in fact
astronomical (and not a local mobile phone, for example). All this assumes that
the mystery signal will continue for long enough for the checking procedure to
be completed, which in practice could take several hours. But if a telescope
detects a momentary blip, there one moment, gone the next, the checking
procedure isnot possible. The biggest drawback of conventional SETI is the
immense time required for radio signals to pass between the stars. But there is
an-other,
more exciting, possibility. Humans could conduct a conversation
with an alien intelligence by proxy on a nearly real-time basis if the aliens
have sent a probe to the solar system, where the travel time for signals to earth
is measured in minutes or hours. Ronald Bracewell raised this possibility at
the inception of SETI, and it has been a recurring theme ever since. From the
standpoint of the aliens, the big plus of a probe is its “set and-forget”
character. With careful design, it might well outlive the civilization that
launched it. It doesnot need a massive antenna, unless required to report back
to HQ on the home planet. Radio telescopes on earth had no trouble picking up
the Pioneer 10 spacecraft at the edge of the solar system (before it finally
blinked off the air a few years ago) and its transmitter was no more powerful
than a Christmas tree light bulb. An alien probe could store a huge amount of
information in a tiny chip; once in communication with us, its supercomputer
could engage in an intensive educational and cultural exchange. In principle,
the probe could be any size at all, but for now I have in mind something the
size of a human communications satellite. In the not too distant future,we hope
thathumans will be able to build micro or nano-machines that store prodigious
amounts of information, and they could be used as space probes. Because of
their tiny size, they could be accelerated to high speeds (say 0.01% of the
speed of light) very cheaply, perhaps without the need for rockets. It may
still take a few million years for them to reach the target stars, but haste is
not an issue in the scenario I am exploring. We can readily imagine an advanced
alien civilization packaging mini-databanks in microscopic capsules and spewing
them around the galaxy in the millions.
Possibility of Life inOur Solar System in thePlanets like Mars,Venus,
Saturn or inOur Moon
We authors are now going to discuss some of important
features of our planetary and our lunar environments which strongly contraindicate
presence of life on our moon, on Venus, or even on Mars. Let us (authors)consider
first the effect of temperature of the surfaces of these planets. Although many
organisms have only a limited temperature range to evolve and to survive, such
as the blue-green algae-can withstand greater extremes. Blue-green algae werereported
growing also in hot springs of the earthat temperatures approachingtowards 100°C.
Othermicroorganisms or organisms multiplyvery slowly attemperatures close to 0°C.
At much lower temperatures, vital activity of all organisms must
cease ascellular cytoplasmfluid becomes frozen.Howeverat very low temperatures,
in liquid nitrogen,genetics, ‑80°C),
many organisms could presumably be preserved forindefinite time although they
would not metabolize or grow. Many organisms are destroyed while inpasteurization
of milk. Standard bacteriological sterilization technique calls for
sterilization at 15 £ steam pressure for 15 min. This procedure
occasionally fails to destroy however some spores. However, a longer period of
exposure is successful. When exposed to dry heat, temperatures of 170°C are
required if sterilization is to be accomplished in 15 min. Four mechanisms
involved in sterilization can be recognized.Destruction ofany cell at 60°Cprobably
due to de-naturation
of proteins, and failure of thermophiles (those bacteria which can withstand
100°C or more like Streptococcus mitis)
to be destroyed at this temperature perhaps reflects utilization of a different
type of protein (e.g., collagen proteinsdo not coagulate at 600°C).
Sterilization at 120°C in saturated steam indicates destruction of some of the
many hydrolysable chemicals of the organisms such as proteins and nucleic
acids. Thereare indications that oxidation has a major destructive role when
sterilization is carried out in dry air.
A fundamental
limitation is that of the instability of organic substances and amino acids.Almost
all organic chemicals becomethermodynamically unstable and become degrade at
rates which in the region of interest are exponentially increased with small
elevations in temperature. For instance, Alanine, one of the most stable amino
acids, is half destroyed in about 10 min at 300°C, in 10 h at 250°C,
and in 30 days at 2000°C.This well-known dependence of reaction kinetics
on temperature is also noted in the destruction of bacteria and sporeswith
rates changing by a factor of 10 for each 70 to 100°C in moist heat or for each
150 to 350°C in dry heat. Long exposures to temperatures below the conventional
sterilization regime may result in destruction of the organism. For instance,
one in 100,000 spores of the thermophilic facultative anaerobe Bacillus stearotheormophilus can survive
42 sec of exposure to superheated steam at 1770°C and only the same
fraction survive after 4,680 min of exposure at 1210°C.This data suggest
that comparable destruction would occur in 100 days at 1000°C with dry
heat.
The whole
question of thermal stability of some bacteria and spore organismsrequires
however more study, particularly observations of time-death curves for extended
periods at lower temperatures and very hot temperature of 1770°C. However, it
is unlikely that any present terrestrial form of any carbon basedlt handed
coileddouble helix DNAlife can withstand long exposure to temperatures above 1800°C
even under the most favorable conditions given by any forms of adaptation. Nor
does it seem likely that throughor by process of adaptation in any planets a
thermally resistant strain might be evolved in others planets whichwould be
strikingly more resistant than those now known.
Water is a
second important requirement of any carbon based double helixDNA living
organisms whatever it may be when it has protoplasm or nucleoplasm in its cell
structure. Although some organisms and spores successfully withstand
desiccation and resume vital processes on or after rehydration, growth and
reproduction occur only when they aregiven the hydrated state. Oneof the most
striking examples is the water requirement of roots of plants. Researchshowed
that most plants will grow if the relative humidity of air in soil is between
98.91 and 99.83% but not at 98.90%, although at this lower humidity most plants
remain alive.
Another example,to me,moist meat is an excellent
culture medium for anaerobic bacteria. However, if the meat is kept dried and
maintained at a relative humidity of less than 20%,bacterial attack ceases.
Consider the fate of a small amount of physiologicalsaline solution, when it is
exposed to air of low humidity. Water, of course, is lost.Ultimately the volume
diminishes until the solution is supersaturated and NaClbegins to crystallize
out. If the relative humidity is less than about 30%,the process continues
until only dry solids remain. Protoplasm of any cellalso behaves in asimilar
manner, having no special affinity for water. At relative humidity ofabout 30%
and below, terrestrial living matter eventually loses nearly all its water.It
is a well-known fact that all growing and dividing cells are made of jelly like
cytoplasm,
and in the nucleus, nucleoplasm,and these
consistmostly of water. Why is water essential to living things? Many answers
maybe given. Dehydrated protoplasm is very hard and stiff. How could then
chromosomaldivision and the other essentials of reproduction, including
reorganization of cells,occur in that dry state? How could transfer of
metabolites occur? Many syntheticsteps seem to involve assembly lines on which
metabolites are handed along.Many millions small molecules move freely within
the cell. The cellular fluid, which is mainly ofcourse, water in this earth,acts
as a highway for rapid transfer of many substances inside or outside the cell.
Lifewithout water would be thus a very slow process, limited by solid state diffusion.
Or it might be another kind of life involving gaseous diffusion process of
cells or a different cellularfluid other than water. May be methane?.Water
also enters into many of the chemical processes of the cell as a reactantand as
such is completely essential to metabolism. Many biological reactionssuch as
hydrolysis of proteins, esters, carbohydrates, and nucleic acids involveliquid
water as a reactant. These reactions often are characterized by small negative
free energy changes. Thus, in the hydrolysis of proteins, values in therange
of3,000 cal/mol have been quoted. In utilizing protein as food or
inreorganizing protein into new configurations, the organism can
take advantage ofthis free energy change, and if a catalyzing enzyme is present,
the reaction occursquickly. If liquid water is not present, the fugacity of
water is diminished and the free energy released in these hydrolysis reactions
can be changed substantially.For instance, if the partial pressure of water
were 1/1000 that of saturation, freeenergy of hydrolytic reactions would be
changed about +4 kcal/mol at 20°C.In such an environment,
peptides would not hydrolyze but rather the reversereaction would occur
spontaneously. The amino acids and proteins would tend toreact to form
impossibly large molecules and the living system could not function unless a
means were devised to prevent untoward polymerization.The great capacity of
organisms to adapt is often cited. Superficially, the differencebetween a
bacterium and a human is enormous. However, when examinedin the light of
comparative biochemistry the contrast blurs. In detail,most of the
important features are virtually identical, including the principal aminoacids,
enzyme systems, and the nucleic acids. The capacity of microorganismsto adapt
is likewise often told, but the actual alterations in enzyme systems ornucleic
acids (as a result of adaptation) are relatively trivial. Observation of
thecapacities of living systems on this earth provides no basis for optimism
that through adaptation, terrestrial organisms could
circumvent the facts of thermal instability or those of chemical thermodynamics
if the organisms are carbon based DNA or RNA Life.
Let me now turn then to a consideration of our
lunar and planetary environments.Mercury can be quickly dismissed. It has no
atmosphere and the face exposedto the sun reaches 340°C, while the dark side
approaches less than absolute zero. The planetsmore distant than Mars are too
cold. Only the moon of Saturn Titan, Venus, and Mars may deserveserious
consideration.
Our lunar surface presents a singularly hostile
environment, with temperaturesranging from intense cold at night to 1350°C at
the lunar equator. There is essentiallyno atmosphere, but rather a very high
vacuum. Intense lethal solarradiation penetrates to the lunar surface. No
liquid water is present. Watsonet al.estimated
that the vapor pressure of water on the moonis 1.4×10-12 mm of mercury[24].
This corresponds to 3.5×10-13 of the saturationvapor pressure at 0°C.
Under these conditions, free energy of reactions
involvinghydrolysis would be changed by nearly +16 kcal, which would
constitute anenormous driving force toward polymerization of proteins. If an
organism wereto accompany a lunar rocket to the moon, its prognosis would be
indeed dubious.On exposure to the sun, unless completely encased in protective
vacuum-tightspace suit, its water simply would boil away and its organic
components would be gradually destroyed by radiation and heat. However a multi-cellular
organism,
microscopic Taradigrades (also named as water bears)which is the toughestanimal
which has everbeendocumented (they canhoweverproduceglass like hard shieldsin
their cells to protect themselves in extreme hot above 1800°C and in
extremecold conditions and without water)can survivein spaceandin everywhereto
be present in the soil of our (in April 2019from the Israel lunar Lander named
Bereshhet, crashed on the moon in lastyear April) lunar surfacesurvived the
crashin thousands.This space craftthat crashedwhile landed on moonon last
spring in 2018had been carryinga backup of planet earth.The mission foundationa
nonprofit organization, that aimedto amass librariesand
store themin variousspots around the solar systemfor safe keeping. This particular
collection containedhuman DNA samplesof human faces in international space
station, a CDRom like disc inscribed with 30 million pages of information and
dehydrated Tardigrades. When Targrades are dehydrated, they are
virtually indestructible. On the face of danger, they enter this near death
state on their own and can manage to survivewithout water or even air, in
extreme hot or cold temperature where no microorganism cangrow or colonize,until
conditions improve. They can live this way for decades after decadeswithout an
issueand when rehydrated, theyinstantly resume life as
normal.If the lunarlibrary isremained intactthrough the crash,
it may be possiblyfor future missions to retrieve itand conduct tests on
tardigrades once they areback on the earth;until thenthere is
a strong likelihoodthat earth is no longer the onlycelestial bodyin our solar
system that are supporting life.
The moon is, of course, always close to us and
relatively easy to study. Venus and Mars are not so readily observed, nor so
definitely known. One measure of thedifficulty. of obtaining
trustworthy information concerning composition of theplanetary atmospheres is
the disagreement among authorities concerning fundamentalfacts. For instance,
Menzel and Whipple suggested that the surface of Venus might be completely
covered by an ocean [25].
There are features of the planetary environment,
however, which seem wellestablished and which have important bearing on the
questions of extra-terrestriallife.Venus has an atmosphere and is covered by a
dense cloud layer. These featuresare especially evident at inferior conjunction
when Venus appears as a crescentand the horns of the crescent are extended to a
variable degree. In contrast tothe moon and Mercury, which have no atmosphere
or clouds, Venus has a highalbedo-,a relatively high fraction
of incident light is not absorbed. What is thecomposition of the atmosphere?
Only one component has been quantitativelydetermined, carbon dioxide. The
measurement of this component, which was atriumph of astronomy, was performed
by Adams and Dunham in 1932[26]. Laterworkers were able to make an improved
estimate of the carbon dioxide content,which is now generally accepted as totaling
1,000 m atmospheres. Attempts to detect water or oxygen in the atmosphere
of other planets arehampered by the absorption of light by these components in
our own atmosphere.
However, it is possible to take advantage of a
Doppler shift in wavelength, which Dunham described in the following:"A
qualitative examination of the infrared spectra of Venus failed to reveal any components
of the oxygen lines in the B band or of the water-vapor lines near8,000 A
which could be attributed to oxygen or water in the atmosphere of Venus[26, 27].VOL, the radial velocity of
the planet averaged 14 km/sec during the period of observing,and this
would correspond to a separation of 0.37 A in the spectrum. "On the
basis of the present evidence, it seems unlikely that there can be morethan 5%
(probably less than 2%) as much of either oxygen or water vapor in the
atmosphere of Venus as in the atmosphere of the earth.".Wheninvestigated
the atmosphere of Venus using a telescopein a balloon,it was alsoreported
finding a trace of water-approximately 19 µm water equivalent above the
cloud layer. The probable error of this measurement,however, wasalmost as large
as the effect observed. Interpretation of these findings was of course,
difficult, for they essentially pertain to that portion of the atmosphereabove
the clouds. We do not know how much water is beneath.Owing to the continual
presence of clouds high in the atmosphere of Venus,it is not possible to
determine the temperature of the surface by measurementsof radiation of
wavelength near the maximum on the black body emission curve.The best estimate
comes from measures at cm wavelengths far to the long wavelength side of the
black body maximum. The temperatures reported for thesurface of Venus are in
excess of 3000°C, which is, of course, far too hot to permit terrestrial life
or complex organic substances to exist. This high temperatureseems acceptable
to most astronomers. They point to the effectiveness of carbon dioxide and
cloud cover in conserving heat in a way often called a greenhouse effect.
Solar radiation is absorbed at the surface, which
re-emits radiation of longer wavelength, mainly in the infrared. The blanketing
atmosphere is relatively opaque to this radiation. Hence heat is conserved. A
similar greenhouse effect is activeon earth where the carbon dioxide content is
only 2% that of Venus.
We turn then to Mars, which has always been
regarded as the likeliest candidate for extra-terrestrial life. Mars has an
atmosphere and, though on the average is colder than earth, has temperatures
which at least part of the time are suitable for life. Temperatures at the
equator rise to 350°C during the day time. At night,
theyfall far' below freezing since there is
practically no cloud cover and greenhouse effect. The atmosphere is relatively very thin and the
surface is visible most of the time. The quantity of gas in the atmosphere was
determined most accurately by Dollfus,who measured the light reflected by the
planet and determined what part was reflected from the surface and what part
was due to Rayleigh scattering in the gas [28].The value which is generally
accepted is a pressure of 85 millibars at ground level.
What does this atmosphere consist of? Our knowledge
is incomplete. Kuiper 6 showed that the gas is carbon dioxide and nitrogen[29].
Some of it is doubtless A40,arising out of decay of K40. The remainder is
generally assumed to be largelynitrogen, although there is no direct evidence
for its presence. There is disagreement concerning a haze in the atmosphere of
Mars which leads to absorption that increases rapidly at wavelengths below 4500 A.
At least threeexplanations have been advanced. Kuiper"7 states that the
haze is due to verysmallice crystals. Opiki8 attributes the absorption to
carbon-containing particulatematter. Another explanation, advanced by Kiessis
that the absorption is due to nitrogen. Mars is smaller than earth and
correspondingly gases can escape far more readily.Only hydrogen and helium can
leave earth, but it has been calculated that even atomic oxygen can escape from
Mars10 It would be a most remarkable circumstance if we were to be especially favored
with the privilege of being around to witness escape of the last traces of
original water from Mars. It has been suggested that water could be supplied by
planetary out gassing. At best, such asupply would be then sporadic.
Volcanic activity on Mars had been also reported.In any event, the present
moisture content of the Martian atmosphere is somewhat adequate to permit life as
we know it to grow and reproduce.There is evidence, though not very convincing,
of life on Mars. The well-known seasonal pattern of color variation has often
been interpreted as of biologicorigin. Following dust storms, earlier color
reappears. Sintonhas measuredthe infrared spectra of light reflected from Mars
and suggested that his spectraindicate the presence of organic molecules for
development of life [30]. The effects observed are smallhowever, Abelsonconsidered
that they can also be explained as due to nitrogen oxides [31]. If these oxides
are present in substantial amounts at the surface of Marsthey would constitute
a toxic hazard to any terrestrial life which might reach Mars.If life actually
would exists on Mars it cannot be like any terrestrial form of life because of
the relative absence of water. The crucial difficulty is the inability of life
to function in a non-fluid state. If there is life, special arrangements to
provide fluidity must be available, e.g. organic liquids of low vapor pressure.
Such a form of life would be quite different from anything we know and would
probably be destroyed in any standard culture medium.
Samples those are likely to contain evidence of past life on Mars must had been deposited when and where environments exhibited habitable conditions. Mars analog sites provide the opportunity to study how life could have exploited such habitable conditions. Acidic iron- and sulfur-rich streams are good geo chemical analogues for the late Noachian and early Hesperian, periods of martian history where habitable conditions were widespread known. Past life on Mars would have left behind fossilized microbial organic remains. These are often-sought diagnostic evidence, but they must be shielded from the harsh radiation flux at the martian surface and its deleterious effect on organic matter. One mechanism that promotes such preservation is burial, which raises questions about how organic bio markers are influenced by the post burial effects of diagenesis. When investigated the kinetics of organic degradation in the subsurface of Mars. Natural mixtures of acidic iron- and sulfur-rich stream sediments and their associated microbial populations and remains were subjected to hydrous pyrolysis, which simulated the increased temperatures and pressures of burial alongside any promoted organic/mineral interactions. Calculations were made to extrapolate the observed changes over martian history. Our authors experiments indicate that low carbon contents, high water-to-rock ratios, and the presence of iron-rich minerals combine to provide unfavorable conditions for the preservation of soluble organic matter over the billions of years necessary to produce present-day organic records of late Noachian and early Hesperian life on Mars. Successful sample selection strategies must therefore consider the pre-, syn-, and postburial histories of sedimentary records on Mars and the balance between the production of biomass and the long-term preservation of organic bio markers over geological time. Success in the search for evidence of life on Mars depends on selecting the appropriate samples for investigation. The late Noachian and early Hesperian period of martian history provide samples of a time when conditions were habitable and when any martian life would have had a relatively lengthy opportunity to originate and proliferate . During the Hesperian period of Mars' history, acidic, sulfur-rich conditions led to the regional deposition of abundant sulfate minerals, such as gypsum (CaSO4·2H2O) and jarosite (KFe3+3(OH)6(SO4)2), in aqueous conditions . Although the longevity of these environments is uncertain, they may have been capable of supporting extremophilic organisms that produced organic remains that, when entombed in a mineral matrix, could represent fossil organic bio markers in the martian rock record. For this reason, there has been significant interest in the ability of jarosite, or minerals associated with jarosite, to preserve organic matter Recent work by Jonathon Tan and by Mark a saphton had shown that lipids are concentrated in iron oxyhydroxides (such as goethite) associated with acid sulfate environments and can preserve fatty acid profiles beyond the initial stages of diagenesis ( Jonathon Tan et al., 2018). The iron oxides and oxyhydroxides present in these environments have also been found to be significantly more amenable to thermal extraction techniques (e.g., pyrolysis) used to search for organic matter when compared with minerals that release oxygen upon heating, such as sulfates (such as jarosite) and perchlorates (Jonathon Tan and by Mark a saphton ). Consequently, iron oxides and oxyhydroxides associated with sulfur stream environments should be considered targets of astrobiological interest. Little is known, however, about how organic biomarkers might be degraded by reactions involving both the organic and inorganic constituents of these acidic iron- and sulfur-rich stream samples, especially following burial where temperature and pressure are elevated for extended periods of time. If life arose on Mars at the same time as Earth, when conditions on both planets were relatively similar, its remains would need to survive billions of years to be detectable in the present day. Although the martian ultraviolet (UV) flux may have been comparable with early Earth and hence not an inhibitor of the evolution of early life (Jonathon Tan and by Mark a saphton ), the cumulative effects of UV radiation over martian history would likely have destroyed all traces of surface organic matter, or at the very least have rendered organic biomarkers indistinguishable from abiotic carbon sources. Radiation raises some concerns for iron-rich environments, as iron may promote the destruction of organic matter in Mars' present-day radiation environment . Thus, to avoid the deleterious effects of UV radiation, rocks containing organic biomarkers would need to have been rapidly transported to the subsurface where further exposure to the effects of UV would be avoided . Buried surfaces can be accessed in the present day by using a drill as planned in the forthcoming ExoMars (2020) mission (Vago et al., 2016), or by searching for surfaces that have only relatively recently been exhumed such as near escarpments or sites of impact ejection . Burial on Mars is relatively rare owing to a lack of plate tectonics, but does occur mostly following continuous sedimentation and subsequent compaction, as observed in Gale Crater . The sediments observed at Yellow knife Bay, for example, were deeply buried and exhumed before 3.3 to 3.2 Ga, and analysis of the hydraulic fracturing within the mud stones of this unit shows a minimum burial depth of 1.2 km . Peak burial temperatures at such depths would depend on the geothermal gradient, which has changed throughout Mars' geological history. Present-day estimates range from 6.4 to 10.6 K/km (Hoffman, 2001), while modeling of the diagenetic history of Gale Crater suggests a time-dependent variable geothermal gradient, with peak paleotemperatures for sedimentary rocks at Gale Crater ranging from 80°C to 225°C, depending on factors such as surface temperature, overburden thickness, thermal conductivity, and heat flow. Consequently, organic biomarkers that have been buried will have been subjected to other potentially degrading mechanisms, and must have been able to survive elevated temperatures, pressures, and degradative reactions involving the interaction of minerals with organic matter.To achieve a full appreciation of how organic biomarkers could be preserved on Mars, it is important to understand how these materials are influenced by the post burial effects of diagenesis, especially with regard to the interactions between organic matter and the mineral matrices present in these distinct martian geochemical environments. Previous studies of Mars-relevant sulfur-rich analogues examined surface conditions where extant biomass was still present. The ability of organic matter hosted in Mars analog settings to survive the initial stages of diagenesis and subsequent burial and thermal maturation has not been previously addressed (e.g., Fernández-Remolar, 2003; Benison and Bowen, 2006; Parenteau et al., 2014; Williams et al., 2015; Tan et al., 2018)Hydrous pyrolysis is a well-known technique used to artificially mature organic matter-rich samples in the laboratory , but has also been used to simulate the effects of diagenesis on certain biomarkers ( Jaeschke et al., 2008). Hydrous pyrolysis involves heating a sample containing both sediment and organic matter in a closed system in the presence of an inert atmosphere and deoxygenated water at subcritical temperatures for 72 h . Historically, hydrous pyrolysis has been used to study rocks with a high total organic carbon (TOC) content, with diagenesis being studied at temperatures between 160°C and 280°C (Eglinton and Douglas, 1988; Peters et al., 1990; Koopmans et al., 1995) and catagenesis being investigated between 300°C and 365°C (Lewan et al., 1979). Iron-rich rocks with low TOC, such as those found in Mars analog environments, have thus not been widely investigated by using this method. In this study, microbial mat materials hosted in two mineralogically distinct Mars-relevant acidic iron- and sulfur-rich stream environments were artificially matured with hydrous pyrolysis to investigate the effects of thermal diagenesis and associated mineral matrix-assisted reactions on the preservation of organic matter within these sa 018).
Samples those are likely to contain evidence of past life on Mars must had been deposited when and where environments exhibited habitable conditions. Mars analog sites provide the opportunity to study how life could have exploited such habitable conditions. Acidic iron- and sulfur-rich streams are good geo chemical analogues for the late Noachian and early Hesperian, periods of martian history where habitable conditions were widespread known. Past life on Mars would have left behind fossilized microbial organic remains. These are often-sought diagnostic evidence, but they must be shielded from the harsh radiation flux at the martian surface and its deleterious effect on organic matter. One mechanism that promotes such preservation is burial, which raises questions about how organic bio markers are influenced by the post burial effects of diagenesis. When investigated the kinetics of organic degradation in the subsurface of Mars. Natural mixtures of acidic iron- and sulfur-rich stream sediments and their associated microbial populations and remains were subjected to hydrous pyrolysis, which simulated the increased temperatures and pressures of burial alongside any promoted organic/mineral interactions. Calculations were made to extrapolate the observed changes over martian history. Our authors experiments indicate that low carbon contents, high water-to-rock ratios, and the presence of iron-rich minerals combine to provide unfavorable conditions for the preservation of soluble organic matter over the billions of years necessary to produce present-day organic records of late Noachian and early Hesperian life on Mars. Successful sample selection strategies must therefore consider the pre-, syn-, and postburial histories of sedimentary records on Mars and the balance between the production of biomass and the long-term preservation of organic bio markers over geological time. Success in the search for evidence of life on Mars depends on selecting the appropriate samples for investigation. The late Noachian and early Hesperian period of martian history provide samples of a time when conditions were habitable and when any martian life would have had a relatively lengthy opportunity to originate and proliferate . During the Hesperian period of Mars' history, acidic, sulfur-rich conditions led to the regional deposition of abundant sulfate minerals, such as gypsum (CaSO4·2H2O) and jarosite (KFe3+3(OH)6(SO4)2), in aqueous conditions . Although the longevity of these environments is uncertain, they may have been capable of supporting extremophilic organisms that produced organic remains that, when entombed in a mineral matrix, could represent fossil organic bio markers in the martian rock record. For this reason, there has been significant interest in the ability of jarosite, or minerals associated with jarosite, to preserve organic matter Recent work by Jonathon Tan and by Mark a saphton had shown that lipids are concentrated in iron oxyhydroxides (such as goethite) associated with acid sulfate environments and can preserve fatty acid profiles beyond the initial stages of diagenesis ( Jonathon Tan et al., 2018). The iron oxides and oxyhydroxides present in these environments have also been found to be significantly more amenable to thermal extraction techniques (e.g., pyrolysis) used to search for organic matter when compared with minerals that release oxygen upon heating, such as sulfates (such as jarosite) and perchlorates (Jonathon Tan and by Mark a saphton ). Consequently, iron oxides and oxyhydroxides associated with sulfur stream environments should be considered targets of astrobiological interest. Little is known, however, about how organic biomarkers might be degraded by reactions involving both the organic and inorganic constituents of these acidic iron- and sulfur-rich stream samples, especially following burial where temperature and pressure are elevated for extended periods of time. If life arose on Mars at the same time as Earth, when conditions on both planets were relatively similar, its remains would need to survive billions of years to be detectable in the present day. Although the martian ultraviolet (UV) flux may have been comparable with early Earth and hence not an inhibitor of the evolution of early life (Jonathon Tan and by Mark a saphton ), the cumulative effects of UV radiation over martian history would likely have destroyed all traces of surface organic matter, or at the very least have rendered organic biomarkers indistinguishable from abiotic carbon sources. Radiation raises some concerns for iron-rich environments, as iron may promote the destruction of organic matter in Mars' present-day radiation environment . Thus, to avoid the deleterious effects of UV radiation, rocks containing organic biomarkers would need to have been rapidly transported to the subsurface where further exposure to the effects of UV would be avoided . Buried surfaces can be accessed in the present day by using a drill as planned in the forthcoming ExoMars (2020) mission (Vago et al., 2016), or by searching for surfaces that have only relatively recently been exhumed such as near escarpments or sites of impact ejection . Burial on Mars is relatively rare owing to a lack of plate tectonics, but does occur mostly following continuous sedimentation and subsequent compaction, as observed in Gale Crater . The sediments observed at Yellow knife Bay, for example, were deeply buried and exhumed before 3.3 to 3.2 Ga, and analysis of the hydraulic fracturing within the mud stones of this unit shows a minimum burial depth of 1.2 km . Peak burial temperatures at such depths would depend on the geothermal gradient, which has changed throughout Mars' geological history. Present-day estimates range from 6.4 to 10.6 K/km (Hoffman, 2001), while modeling of the diagenetic history of Gale Crater suggests a time-dependent variable geothermal gradient, with peak paleotemperatures for sedimentary rocks at Gale Crater ranging from 80°C to 225°C, depending on factors such as surface temperature, overburden thickness, thermal conductivity, and heat flow. Consequently, organic biomarkers that have been buried will have been subjected to other potentially degrading mechanisms, and must have been able to survive elevated temperatures, pressures, and degradative reactions involving the interaction of minerals with organic matter.To achieve a full appreciation of how organic biomarkers could be preserved on Mars, it is important to understand how these materials are influenced by the post burial effects of diagenesis, especially with regard to the interactions between organic matter and the mineral matrices present in these distinct martian geochemical environments. Previous studies of Mars-relevant sulfur-rich analogues examined surface conditions where extant biomass was still present. The ability of organic matter hosted in Mars analog settings to survive the initial stages of diagenesis and subsequent burial and thermal maturation has not been previously addressed (e.g., Fernández-Remolar, 2003; Benison and Bowen, 2006; Parenteau et al., 2014; Williams et al., 2015; Tan et al., 2018)Hydrous pyrolysis is a well-known technique used to artificially mature organic matter-rich samples in the laboratory , but has also been used to simulate the effects of diagenesis on certain biomarkers ( Jaeschke et al., 2008). Hydrous pyrolysis involves heating a sample containing both sediment and organic matter in a closed system in the presence of an inert atmosphere and deoxygenated water at subcritical temperatures for 72 h . Historically, hydrous pyrolysis has been used to study rocks with a high total organic carbon (TOC) content, with diagenesis being studied at temperatures between 160°C and 280°C (Eglinton and Douglas, 1988; Peters et al., 1990; Koopmans et al., 1995) and catagenesis being investigated between 300°C and 365°C (Lewan et al., 1979). Iron-rich rocks with low TOC, such as those found in Mars analog environments, have thus not been widely investigated by using this method. In this study, microbial mat materials hosted in two mineralogically distinct Mars-relevant acidic iron- and sulfur-rich stream environments were artificially matured with hydrous pyrolysis to investigate the effects of thermal diagenesis and associated mineral matrix-assisted reactions on the preservation of organic matter within these sa 018).
In contrast, an important caveat of these models is that they only predict the amount of detectable solvent-extractable organic matter remaining in a sample after a certain period. As revealed in the literature (Eigenbrode et al., 2018), it is known that macromolecular organic matter can survive the radiative and diagenetic conditions of martian geological history (although it is important to note that the age of this material is not yet known). Macromolecular organic matter is not solvent extractable and thus was not considered by these sets of models. The model also does not provide insights into whether the remaining organic matter can be distinguished from sources of abiotic carbon, such as meteoritic material (Chyba and Sagan, 1992; Summons et al., 2008; Sephton, 2012) or Fischer/Tropsch-type (FTT) reactions (McCollom and Seewald, 2006; Mißbach et al., 2018). The latter is especially important, as FTT reactions are a common occurrence in hydrothermal deposits (McCollom and Seewald, 2007; Konn et al., 2015) and can produce long-chain saturated fatty acids (Mißbach et al., 2018). Finally, the model does not consider the effects of minerals common to the surface of Mars that are not present in our analog samples, most egregiously the presence of perchlorates in the martian regolith (Carrier and Kounaves, 2015). While we acknowledge the importance of perchlorate minerals, and the complexity of perchlorate mineral interactions with organic matter (Góbi et al., 2017; Fornaro et al., 2018), postulating how it may affect the kinetics of organic matter preservation in the studied environments is beyond the scope of this study.
The late Noachian and early Hesperian represented habitable conditions on Mars contemporaneous with the emergence of life on Earth. We can develop our suite of life detection skills by examining analog sites on Earth that are chemically and possibly biologically similar to the late Noachian and early Hesperian of Mars. Acid iron- and sulfur-rich streams and the microbial communities hosted within these environments provide one such analog site. Rocks representing the late Noachian and early Hesperian of Mars are old and any organic matter within would have been stored for billions of years. Samples that are likely to contain evidence of past life on Mars must exhibit conditions that promote the preservation of organic biomarkers over geological time.Artificial maturation techniques can recreate the effects of geological storage on Mars in Earth laboratories and allow us to draw conclusions about the behavior of organic biomarkers in response to diagenesis in these distinct geochemical environments. Fatty acids are found to be persistent organic biomarkers, but complex organic structures are susceptible to degradation. During maturation, thiophenes are released at low temperatures and fatty acids are liberated from adsorption sites. Low carbon contents, high water-to-rock ratios, and the presence of iron-rich clay minerals are all conditions that decrease the preservation of organic biomarkers in iron- and sulfur-rich stream environments. Kinetic modeling derived from quantitative hydrous pyrolysis, however, suggests that these conditions are applicable only on a 100 kA timescale, after which all solvent-extractable organic matter is expected to be lost.The analysis of kinetic parameters predicts that regardless of the carbon content, water availability, and the presence of clay minerals, saturated fatty acids are not expected to be detectable by wet chemistry techniques following postburial diagenesis. Sample selection on future Mars missions should appreciate that some samples, which reflect habitable conditions on Mars, can inhibit the preservation of martian organic matter when exposed to geological storage over billions of years. Sample selection strategies must therefore consider the pre-, syn-, and postburial histories of habitable conditions on Mars and the balance between the production of biomass and the long-term preservation of organic biomarkers over geological time
DNA/RNA Viruses asData
Rich Signals
Nature
has already invented neatly packaged data-rich nano machines we call them
viruses. A typical virus contains thousands of bits of information encoded in
either RNA or DNA enough for a decent message. So why not engineer trillions of
viruses, package them in pea-sized microprobes and spew them around the galaxy?
Each virus would convey a message for any future intelligent life on the
destination planet, the space-age equivalent of a message in a bottle. The
beauty of the scheme is that the message can be replicated ad infinitum should it encounter life on a destination planet, by
the simple expedient of programming the viruses to “infect” any DNA-based cells
with which they come into contact. The virus inserts its message into the
genetic material of the host organism’s germ cells (that is what so-called
endogenous retroviruses do), and the cell obligingly replicates it and passes
the message on to all future generations. In this way the virus would spread
like wildfire through the host ecosystem, its information preserved for
millions of years until some future Craig Venter begins sequencing genomes and
stumbles across the messagesoil is
between 98.91 and 99.83% but not at 98.90%, although at this lower humidity,
most plants remain alive.
How the Aliens Will Look Like in Other Star’s Worlds exo Planets in Habitable Zones (Figure 3)
Let us to assume that our own humanoid
form is the generic result of an ideal set of criteria by the creator which
hold true universally? Perhaps all biologic life strives for carbon-based,
oxygen-burning chemistry, and to see the planet by the visible light spectrum. There
is no reason these laws should be very much different on other planets of other
stars, if the universe is composed of the same small number of elements, which
seems to be the case.So the aliens will probably have a close/similar
appearance to humans or animals or reptiles in the earth, if they are found to
be living in an environment and climate similar to ours but may appear as
monster based on gravity of that planet. Aliens may have the same DNA as we do
here on earth. There are several types of nucleic acids that might be useful
for genetic storage and transfer of information; tRNA, mRNA, aDNA, zDNA, even
PNA. Three and four stranded varieties sometimes occur.
Fig. 3:
An Exoplanet
in Other Solar System in Habitable Zone.
It is possible that the variety which
life on earth utilizes may predominate on many planets; it might be the most
suitable type for living creatures and will be selected by evolution on a
biochemical level. Even if this is true (and I donot think we can be sure yet)
there are two mirror-image forms of DNA which are possible; we never encounter
the mirror image L-DNA in nature as far as I know (as opposed to zDNA, which is
completely different in form) but it could occur on other worlds. Alien life
might not have DNA like earthlings. Prof Hawking warned: "Watch out
if you would meet an alien. You could be infected with a disease with which you
have no resistance.[4]"
The origin of all
life in this planet, the earth, was at first RNA
world and then DNA world and then first single cell then multi-cellular complex
life and so on and all life has the same depth of evolution .Taking two of the
points shown on the Figure 3, those for fish and mammals which shared a
common ancestor around 500 million years ago; of what relevance to the origin
of life has been the faster development of non-redundant genes in the lineage
leading to mammals? Use of the hypothesized time of ‘origin’ of Eukaryotes,
occurred around 2 billion years(bya) is particularly unfortunate. Firstly, we
do not have any certainty about the timing of the origin of eukaryotes. Comparative
genomic analyses (Figure 4)concluded that the first earthly multi-cellular
eukaryote,
did evolve by 2.7 bya, but the first
proto-eukaryotes may have evolved around 4 bya. There are also
microfossils dated to 3.8 bya which have been interpreted as simplified
eukaryotes.Many others had cited this evidence to argue that eukaryotes did not
at all evolve on earth, but also have an ancestry which predates the origins of
this planetSecondly, the development of eukaryotes was arguably the greatest
leap in evolution since the origin of the first self-replicating cell;
certainly not within the gradualism camp since it resulted from a series of
rare cell-fusions of prokaryotic cells. Once again, we might ask of what
relevance to the timing of the origin of life was this serendipitous event? It
is wrong to place the origin of the prokaryotic cell at 3.5 Gigayears ago.
Although we have evidence of the existence
of prokaryotes at that time we also have evidence that their phylogeny, on earth,
runs much deeper from 3.8 bya. Prokaryotic life appeared
on earth shortly after life became possible on this planet (Joseph and Schild
2010). Ifwe accept the Sharov's (2010) contentions, they may well have existed
10 billion years ago.
In our view all life-forms we might find in the outer solar system will share the genetic codesthat may
be familiar to us. Any experimentation with alternative genetic systems in
primordial cells would have been snuffed out by the development of the RNA
world, which in turn was snuffed out (with the possible exception of some RNA
viruses) by the DNA world. The important question remaining is whether both prokaryotes
and eukaryotes are represented among these life-forms.
We authors think that many alien
intelligent species (perhaps 2 or 3% of them) would look like humanoid as they look, act, think and
feel amazingly like ourselves with probable some kind of appendages evolved for
manipulation, locomotion. These appendages can have evolved from any movable
body parts, including parts of the locomotors apparatus (limbs), feeding
apparatus (mouth parts like lips or mandibles), respiratory apparatus (gills or
lungs), or sensory apparatus (antennae). Earthlike worlds with slightly more
gravity would tend to produce centauroids. The nearest centauroid might look
like the upper part of a gorilla transplanted on the body of a donkey, for
example. And its two eyes might be above each other, rather than side by side.
Earthlike worlds with slightly less gravity would tend to produce flying
aliens. Some might look like bats, others like octopoi with a balloon-like
body, yet others like living monoplanes, with their manipulative extremities
tucked away inside their mouths. In a dense atmosphere a life form might look
like a living umbrella, which keeps a loft by opening and closing itself.
Earthlike worlds with vast tracts of level ground might have inhabitants which
look like giant wheels. The outside of the wheel might be covered with tiny
mouths used for grazing. Ant like creatures and some reptile like, some are giants
larger than elephant also, may be possible, and some like octopus also, aliens
are aliens even we are aliens for them.
The intelligent civilized life in those
planets will probably be humanoid
as a technical term, which I want to denote having a bilateral body plan with a
trunk, two legs, two arms and a head with three eyes. Humanoid species would
not have always to look anything like human beings.
A bilateral symmetrical body plan may
also have possible subdivisions of their body plans as per mathematical laws
and if one observes the life around us in the planet earth evolved, as I had
observed.
Fig. 4:
Comparative Genomic Analyses Concluded that the First Earthly Multi Cellular
Eukaryote, did Evolve by 2.7 bya, but the First Proto-Eukaryotes may have Evolved
around 4 bya.
Symmetry
A: No
discernable symmetry (a bush, an amoeba)
B1:
Spiral symmetry (certain snails)
,
B2:
Helical symmetry (other snails)
,
C2: Bilateral
Symmetry (most vertebrates)
C3:
Threefold cylindrical symmetry
,
C4:
Fourfold cylindrical symmetry,
CN:
N-fold cylindrical symmetry
;
Coo:
Complete cylindrical symmetry (like a jellyfish or a wheel),
D:
Rectangular symmetry (like a two-headed snake or amphisbaena),
,
E2:
Cubical/octahedral symmetry
,
E3: Dodecahedral/icosahedral
symmetry
,
Eoo:
Spherical symmetry.
C2:
Bilateral Symmetry with Appendages
C2.0:
No appendages (like a snake)
,
C2.1:
One pair of appendages
,
C2.2:
Two Pairs of Appendages (like most mammals hands and feet)
C2.3:
Three pairs of appendages (like a centaur)
,
C2.4:
Four pairs of appendages (like a spider)
,
C2.5:
Five pairs of appendages (like a butterfly)
,
C2.N:
N pairs of appendages
,
C2.V:
Variable (large) number of pairs of appendages.
B2.2:
Bilateral Symmetry: Two Pairs of Appendages
B2.2.H:
With a head on one end,
B2.2.T:
With a tail on one end,
B2.2.B:
With a head on one end and a tail on the other end,
(Absence
of both head and tail would make the symmetry rectangular).
Kind
of Appendage:
T1:
Tentacle
,
T2(1,1):
Tentacle, which divides into two sub-tentacles
,
T3(2(1,1)1,1):
Tentacle which divides into three sub-tentacles, one of which divides into two
sub-sub-tentacles, none of which divide any further
,
A:
One rigid part
.
B: Two
rigid parts
.
B2(A2(A1,T1),B1)
Two rigid parts, the last one sprouting two sub-appendages, the first of
which has one rigid part, sprouting yet another rigid part and a tentacle, the
second of which has two rigid parts, sprouting nothing further.
C:
Three rigid parts
C5(B1,C1,C1,C1,C1)
Three rigid parts, the last one sprouting five sub-appendages, one of which has
two rigid parts, the other four having three, none of these subdividing any
further.
C2.2.H; 2B2(C1,A4(C1,C1,C1,C1)); 2C5(B1,C1,C1,C1,C1)
So,any
body structural scheme starting with C2.2.H or C2.2.B will be consideredas
humanoid, unless one or both pairs of appendages are wings or fins.
Our
(authors here) expectation is that of all intelligent species,
a large partin other worlds (perhaps even more than 50%), will have body
schemes starting with C2, and of these the majority will be C2.2 (and these
mostly humanoid) or C2.3 (and these mostly centauroid or angeloid).
Why we
have considered the bilateral symmetry? The advantage of bilateral
symmetrybefore us is thatthat there is a definitive front and back, this allows
the organism to focus its limited senses in a certain direction defined as
"front". If you look at squid and octopi, they actually technically are bilaterally symmetrical. They
have two eyes, an ink gland, a beak, a water jet intake and outlet, and in the
case of squid a pair of feeding tentacles. Despite their eight radially
symmetrical tentacles, these paired or singular structures
give a definitive bilateralness to their structure.
The
most serious limitation for any intelligent life form is however the
developmentnervous system or equivalent thereof for signaling. All life-forms
on earth use ionic gradients as a signaling mechanism. This is the basis of the
animal nervous system, but is also critical to all other life-forms on earth. I
will assume that animals on another world use ionic gradients as the primary
signaling mechanism as well. Chemical transport is far too slow for a mobile
organism.
What
will be their Food Habit?
All
the smartest animals on earth are either carnivores or omnivores, since it is a
lot more difficult for something that eats things that can run away to survive
than something that simply needs to run away. This is because a given level in
the food chain must have 1/10th the biomass of the previous level. The chances
for a herbivore are a lot better than those of a carnivore. Similarly, pure scavengers
probably would not need that high of intelligence.
Conclusionsand Possibility of life in other planets of our own solar system
There
may be no little green men living in our solar system. However, there are
plenty of places where more primitive life might be able to survive. Many
astronomers now believe that life has a good chance of evolving wherever the
conditions are right. So our solar system could be teeming with living creatures.The
main candidates in the solar system to harbor life are Mars, Europa and Titan
and our moon with tardigrades left with
from earth.
Europa is an icy moon that revolves around Jupiter. The temperature
on the surface is a chilly ‑170ºC. But this inhospitable planet may harbor an
underground ocean of liquid water, one of the essential ingredients for life.
REFERENCES
1. John Gribbin.Is Anyone Out There? NASA Researchers
have started to search the Galaxy for Signs of Intelligent Life. What Sort of
Life do they Hope to Find? New Scientist. 25 May 1991; Magazine
issue 1770.
2. Rupak Bhattacharya,
Pranab Kumar Bhattacharya, Upasana Bhattacharya, Ritwik Bhattacharya, Rupsa
Bhattacharya, Dalia Mukherjee, Ayshi Mukherjee, Debasis Mukherjee.Super-Earths (Exo-planets): How Much Probability of
Colonization of Life is There?Journal of
Aerospace Engineering & Technology (JoAET), STM Journal Group.2019; 9(1): 33‑39p.
3. Pranab Kumar
Bhattacharya et al. Rafael Austin and
Thread Answer. http://www.badastronomy.com/phpBB/viewtopic.php?t=4570&sid=46ce3673996d676dc0bdae2e16d1c931.
www.unipathos.com
4. HawkingStephen
W. Life in the Universe. FRS in his
website, accessed by P. K. Bhattacharya.
5.
Rupak Bhattacharya, Pranab Kumar Bhattacharya Upasana Bhattacharya, Ritwik Bhattacharya, Rupsa Bhattacharya, Dalia Mukherjee, Ayshi Mukherjee, Debasis Mukherjee. Schrödinger Cat's Experiment's Interpretation andParallel Universe or Multiple Universes. Research & Reviews: Journal of Space Science & Technology (RRJoSST), STM Journal Group. 2016; 5(1): 35‑52p.
Rupak Bhattacharya, Pranab Kumar Bhattacharya Upasana Bhattacharya, Ritwik Bhattacharya, Rupsa Bhattacharya, Dalia Mukherjee, Ayshi Mukherjee, Debasis Mukherjee. Schrödinger Cat's Experiment's Interpretation andParallel Universe or Multiple Universes. Research & Reviews: Journal of Space Science & Technology (RRJoSST), STM Journal Group. 2016; 5(1): 35‑52p.
6. Cronin
JR, Cooper GW, Pizzarello S. Characteristics and Formation of Amino Acids and
Hydroxy Acids of the Murchison Meteorite. Adv
Space Res. 1995; 15(3): 91–97p.
7. Cronin
JR, Pizzarello S. Enantiomeric Excesses in Meteoritic Amino Acids. Science. 1997; 275(5302): 951–955p.
8. Pizzarello
S, Cronin JR. Non-Racemic Amino Acids in the Murray and Murchison Meteorites. GeochimCosmochimActa. 2000; 64(2):
329–338p.
9. Bernstein
MP, Dworkin JP, Sandford SA, Cooper GW, Allamandola LJ. Racemic Amino Acids
from the Ultraviolet Photolysis of Interstellar Ice Analogues. Nature. 2002; 416(6879): 401–403p.
10. Muñoz
Caro GM, Meierhenrich UJ, Schutte WA, Barbier B, Arcones Segovia A, Rosenbauer
H, Thiemann WH, Brack A, Greenberg JM. Amino Acids from Ultraviolet Irradiation
of Interstellar Ice Analogues. Nature.
2002; 416(6879): 403–406p.
11. Cohen
BA. Racemization of Meteoritic Amino Acids. Icarus.
2000; 145(1): 272–281p.
11a] Roger Highfield, Science Editor.http://www.telegraph.co.uk/science/science-news/3340426/Stephen-Hawking-Aliens-probably-exist.html.
Telegraph News;22 Apr 2008.
11b]Engel
MH, Macko SA.Isotopic Evidence for Extraterrestrial Non-Racemic Amino Acids in
the Murchison Meteorite.Nature. 1997;
389(6648):265–268p
12. John Pickrell.Top 10: Controversial Pieces of Evidence
for Extraterrestrial Life.New
Scientist; 11:30, 04 Sep 2006. A Mysterious Radio Signal is Received by
the SETI Project on Three Occasions: From the Same Region of Space and 1977,
The Unexplained Extraterrestrial "Wow!" Signal is detected by an Ohio
State University Radio Telescope.
13. Basiuk
VA. Some Observations on Amino Acid Racemization under Pyrolytic Temperatures
and Inorganic Oxide-Catalyzed Intermolecular Condensation. Adv Space Res. 2001; 27(2): 335–340p.
14. Borchers
Andrea T, Davis Paul A, Eric Gershwin M.The Asymmetry of Existence: Do We Owe
Our Existence to Cold Dark Matter and the Weak Force? ExpBiol Med. 2004;
229(1): 21‑32p.
15. Chyba
CF, Thomas PJ, Brookshaw L, Sagan C. Cometary Delivery of Organic Molecules to
the Early Earth. Science. 1990; 249(4697):
366–373p.
16. Chyba
C, Sagan C. Endogenous Production, Exogenous Delivery and Impact-Shock
Synthesis of Organic Molecules: An Inventory for the Origins of Life. Nature. 1992; 355: 125–132p.
17. Kasting
JF. Earth’s Early Atmosphere. Science.
1993; 259(5097): 920–926p. [Abstract]
18. Whittet
DCB. Is Extraterrestrial Organic Matter Relevant to the Origin of Life on
Earth? Orig Life EvolBiosph. 1997; 27(1‑3):
249–262p.
19. Raulin-Cerceau
F, Maurel MC, Schneider J. From Panspermia to Bioastronomy, the Evolution of
the Hypothesis of Universal Life. Orig
Life EvolBiosph. 1998; 28(4‑6): 597–612p.
20. Clark
BC. Planetary Interchange of Bioactive Material: Probability Factors and
Implications. Orig Life EvolBiosph.
2001; 31(1‑2): 185–197p.
21. Mileikowsky
C, Cucinotta FA, Wilson JW, Gladman B, Horneck G, Lindegren L, Melosh J,
Rickman H, Valtonen M, Zheng JQ. Natural Transfer of Viable Microbes in Space.Icarus. 2000; 145(2): 391–427p.
22. Horneck
G, Rettberg P, Reitz G, Wehner J, Eschweiler U, Strauch K, Panitz C, Starke V,
Baumstark-Khan C. Protection of Bacterial Spores in Space, a Contribution to
the Discussion on Panspermia. Orig Life
EvolBiosph. 2001; 31(6): 527–547p.
23. 23] Intelligent
Life in Galaxy Define Intelligence Thread at BAD Astronomy & Universe Today
www.bautforum.com by
24. Watson K, Murray B, Brown H. J Geophys Res. 1961; 66(May issue).
25. 26] Menzel, D. H., and F. L. Whipple,
Publ. Astronom. Soc. Pacific, 67, 161 (1955).
26. Adams WS, Dunham T Jr. Pub. Astronom. Soc. Pacific. 1932; 44: 243p.
27. Dunham T Jr. In Kuiper GP, editor. The Atmospheres of the Earth and Planets. 2nd
Edn. Chicago: The University of Chicago Press; 1952; 295p.
28. Dollfus A. C.
R. Acad Sci. 1951; 232: 1066p.
29. Kuiper GP. In: Kuiper GP, editor. The Atmospheres of the Earth and Planets.
2nd Edn. Chicago: The University of Chicago Press; 1952; 389p.
30. Sintorn WM. Science.
1959; 130: 1234p.
31. Abelson Philip H. Extra-Terrestrial Life. Proc Nat ScienceUSA Geophysics. 1961; 47(4):
575‑581p.
.
]
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