There are several reports on bacterial fossils and organic matter from meteorites. Bacterial spores can remain viable in very harsh conditions. Taking these reports into consideration, could it be possible that life on earth was introduced through meteorites?
Scientifically, I don't completely agree with the second point made by Markus because,
A) Extremophile organisms which include bacteria survive the harshest environment on Earth, such as acidic/basic conditions, radiation and temperature above and below 100 degress centrigrade.
B) A camera left on the moon by an Apollo mission when collected after a span of 3 years by a later mission had viable bacteria growing in it (check: http://www.bbc.co.uk/learningzone/clips/bacteria-survive-nearly-three-years-on-the-moon/9931.html).
Therefore, meteorites sustaining some form of bacteria which have the capability to survive in all the harsh environments imaginable in space is not very unlikely.
Is it possible?
Yes. Is it likely? Absolutely not (my opinion.
First, the reports are on structures found in meteorites resembling bacterial fossils only. Second, the survival of spores in interstellar space is very unlikely, but it is even more unlikely that a meteorite containing extraterrestrial life would leave its solar system and then "just hit" a planet capable of supporting life.
Hi,
interesting topic indeed. Dully agreed with Jan about panspermia options. Outside the scientific probability, a little spam - a similar theory was presented in "The Andromeda strain" (Michael Crichton) like a possibility for aliens to send messengers in form of spores(small sizes, durability ...).
Scientifically, I don't completely agree with the second point made by Markus because,
A) Extremophile organisms which include bacteria survive the harshest environment on Earth, such as acidic/basic conditions, radiation and temperature above and below 100 degress centrigrade.
B) A camera left on the moon by an Apollo mission when collected after a span of 3 years by a later mission had viable bacteria growing in it (check: http://www.bbc.co.uk/learningzone/clips/bacteria-survive-nearly-three-years-on-the-moon/9931.html).
Therefore, meteorites sustaining some form of bacteria which have the capability to survive in all the harsh environments imaginable in space is not very unlikely.
Dear Kunal,
the conditions extremophile organisms can tolerate are still very hospitable compared to the vacuum in interstellar space. Moreover, we are talking about long time-spans for interstellar travel. The next solar system to ours is some 4-5 light years away, and an object at the speed of e.g. Voyager I would need 80,000 years (http://en.wikipedia.org/wiki/Interstellar_travel#Travel_time). And thats for an object that has a targeted course....
Congratulations! Great Topic, Dense Discussion! Please, fellows, continue.
Here is something interesting for this discussion-
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2832349/
Jan,
you are of course right, even unlikely events (or events we beleive to be unlike) do happen. But i was pointing the likelyhoods out because its a usual concept in science to favor those theories that are more likely and especially those that are not unnecessarily complicated (Occams razor).As Kenneth pointed out, even if life came to earth from outer space, this wouldnt add anything to our understanding of the origin of life, it would just change the location and introduce another problem, i.e. that of interstellar space travel. There is an excellent wiki entry that has many interesting aspects: http://en.wikipedia.org/wiki/Panspermia.
As the universe is full of water and many organic compounds, one can assume the origin of cellular live somewhere on distant/ancient planet.
Taking in account some knowledge about evolution of galaxies and planets we can consider this, of course very speculative, paper: http://arxiv.org/abs/1304.3381
This approach give very long time for evolution and complexity accumulation :-)
Kenneth,
thats not the way i understand Occam's Razor. In light of new findings, observation and experimental results any hypothesis / theory needs to be adjusted or expanded. There is no requirement that everything is known about a subject (if thats possible t all).
http://en.wikipedia.org/wiki/Occam%27s_razor
We have many types of panspermia as necropanspermia, reversed panspermia, lithopanspermia etc. If Vreeland has rigth, the living bacteria can survive long time in space. But cosmic rays and time can be problematic. Moreover how living microorganisms came into meteorites or planetoids?
In our scientific exploration and definition of alien lifeforms, we interpret them on the basis that an organism will be completely based upon organic (carbon based) backbone.
Are we not leaving out the possibility that in another world with different elemental composition and atmospheric conditions (perhaps, non-oxidizing environment), a living organism would incorporate the most easily available element into its backbone structure and transform itself in order to sustainable itself in an environment which would be extremely harsh in our understanding.
Read: http://www.nasa.gov/topics/universe/features/astrobiology_toxic_chemical.html
Kunal,
if we put this under the perspective of the original question that would mean that a different life form inoculated earth, somehow triggered the emergence of life on earth as we know and then got extincted without leaving a trace...
Kunal,
it might be important to know that several people took issues with this claim and the related publication of the link you posted. As far as i am aware the claims have not been validated.
Kenneth,
if we want to explore all the crazy possibilities i absolutely agree with you, away with Occam's razor and lets see how the branches of our fantasies grow.
If we want to cut through all these branches to find scenarios that might possibly be true, if we want to discuss which ones are more or less probably (which for this topic is highly subjective), then i say lets put Occam's chainsaw to work.
Thank you all for the tremendous response to my question. I have been enjoying the debate and am very fascinated by some of the points raised. I really hope the discussion goes on.
Our current knowledge is not sufficient enough to have a clear idea on origin of life. Why is it that origin of life still remains a mystery? May be because our understanding of environment which prevailed on earth at time of life's origin is not complete or may be because life originated somewhere else. As Dr Towe said, none of us know what may be found tomorrow.
@Kunal....A very interesting point Kunal, not necessary that organisms on other planet be "carbon" based.
Naveen,
i think you should start a new post for those questions, otherwise its becoming too difficult to follow the thread as there would be too many different subjects.
Ok Markus, I will start a new post for it. I would edit my previous post.
Everyone please have a look at this article
http://www.thehindu.com/sci-tech/science/indiaorigin-scientist-explains-how-life-began-on-earth/article5310447.ece#comments
If i understood this correctly this article proposes that life has emerged with the aid of extraterrestrial material. Hence we would have no direct alien origin (in the sense of alien life-forms coming to earth). Considering that material from comets and meteorites, including the processes happening during their crash on the planet may have triggered the emergence of life on earth one might say that terrestrial life may have had a partial extraterrestrial origin. But this is different from suggesting that extraterrestrial life came to earth. And by the way, the article is a bit misleading as scientifically speaking Dr. Chatterjee proposed a hypothesis that may be supported by some of the data (which is not presented in that article). By no means has he found the answer to the origin of life.
@Kenneth: The article you have pointed out (of scientific american) says that they found nucleobases, sugars, amino acids. But can these compounds really start life? Is the idea that life started on Earth becoming unpopular? Have some people really found some things which can be definite proof beyond doubt that life originated else where and was seeded by meteorites or some thing more complex?
Just for the sake of argument if we build on this notion that life was seeded by meteorites then can this possibility explain the diversity of life which we not only see on Earth today but also have known to have existed through fossils? Can just few million molecules or even bacterial spores can give rise to the tremendous diversity which have lived on Earth?
Nature has to short time for life creating between LHB and first fossils noted in the Earth.
Szostak (2012): What is important in the origin of life field is understanding the transitions that led from chemistry to biology. So far, I have not seen that efforts to define life have contributed at all to that understanding" and „Attempts to define life do not help to understand the origin of life”.
Andrzej
@Kenneth: Yes, I have combined both origin and evolution together because they have to be taken together if one has to arrive at the correct answer to this puzzle. One cannot answer either origin or evolution separately. If origin started due to seeding of either biomolecules or microorganisms then the basic question will be when did this happen? Did this particular seeding provide enough time for the diversity to develop? If the seeding provided time long enough then that means it would be near to the time when we assume the life originate on earth using molecules already available on Earth! And if the seeding occurred later then there was not enough time for this kind of diversity to have evolved.
Also if the seeding was due to microorganisms then the well established microorganisms will not be able to evolve into such diversity as the microorganisms carried with any meteorite would not be able to carry diverse microorganisms.
As Kenneth has said there were two 'rapid' evolution first with development of photosynthetic mo and then after millions of years (Kenneth it should be millions and not billions I think) evolution of multicellular life. Again question comes to mind that if and stress if the initial was seeded from 'somewhere' then was mulicellularity again seeded from 'somewhere'? Because with two different times there was never seen before events taking place by development of complex unicellular in the first and multicellular in the second event?
Complex question, this, but again if it was so simple then we would have studied about it in primary school and not discussing it here!
@Kenneth: Thank you very much for providing such an informative paper of your. It filled in some gaps in my mind. Thanks a lot.
@Kenneth: With complex unicellular life I meant shifting of life from coacervates to true unicellular life. I think the first true unicellular life was complex than a coacervate type life.
Why to bring meteorites into everything? Its beginning to look like these were the Chariots of God but with different meaning from what E Von Daniken had many to believe! Why cannot we believe that we had everything here on Earth to start life. I am not so selfish not to believe that we are all alone in this Universe (or some may say Multiverse!) but we had lots of time on our hand and every possible atoms to kick start life here it self. It is like saying that because the early man was lacking technology he could not had possibly made the pyramids....I think the pyramids were made by us with the technology available at that time and similarly the life also originated here on Earth with the ingredients available here on Earth. The only question to be answered is that how that possibility arose.....but then again there are views markedly different here with people gunning for either DNA or RNA to the first and some brilliant minds of our times have even given a possibility of RNA from heavens (lightning) and protein from dust (clay) making it sound very religious!
Kunal,
there is still the problem of getting that meteorite out of its solar system and hit another one. Even the fact that you may be able to keep bacteria viable in space for a short time doesnt really change anything. I fully agree with Prashant, why look into space for an answer?
Kenneth, your suspicion is correct but I think we are on the other side of the argument and it possible that even though right now we may seem to have all the 'horses' but we may be on the wrong side of the 'river'! But again I fully agree with Marcus that it will be an energy driven activity for a meteorite to leave its own system and head for another system. As far as keeping bacteria viable during long stretches of space for N number of years, I think it is possible if they form spores because spores can survives extreme environments. I want to believe in panspermia or even in alien origin of life but then I do not see any evidence of it and then again the fundamental question of origin of life will remain even though the centre will shift of Earth to 'wherever'.
When I say alien origin I imply that either through panspermia or by 'visitors of other kind' started life on Earth which was earlier barren. But there is another possibility that there was some semblance of life on Earth (like DNA/RNA replicative units) and these original inhabitants of Earth evolved into life as we see in fossils with the help of aliens which came on meteorites.
I am only interested in this topic so that some can give the answer to the question of origin of life whether on Earth or anywhere because even though it matters 'where' life originated but it matters more to answer 'how' life originated.
It will be very interesting to reconstruct position of Solar system and other systems 4,5 biolion (mld) years ago and try to recognize distance to other systems with planets similar as Earth. According me panspermia is the more kikely explanation of origin of life in Earth (especially after last investigations of bacterial extremophiles which can survive very long time distnce)
A
Dear Andrzej, please provide the link for the paper which gives information about the bacterial extremophiles which can survive very long time and distance.
Kenneth, I will like that my aliens are organic life forms with DNA/RNA bases and therefore I have knowingly said in the earlier post that DNA/RNA lifeforms on Earth may have been truly helped by these microorganisms present in the falling meteorites. If life can this from as we know on Earth then it is very much possible that these same elements found all over the Universe (if I may use this term without offending people counting for Multiverse) will behave the exact same way that like they did on Earth as most places have similar physics in the entire Universe.
Even if we prove that life could be brought from one planet to another through meteorites, this will not prove that life arose on Earth by this process. But the question of "life exchange" is relevant because life on Earth and Mars (if exist or existed in the past) might have the same origin (Earth or Mars). This is an important point if we are looking for a second origin or life. See for instance the interesting paper of C. McKay: Phil. Trans. R. Soc. A 2011 369, 594-606.
Kenneth, you are right. But is it possible coexistence of different life style in the same place?
Andrzej
I did not said anything about different life styles, have I? And as far as my knowledge of behavior of any kind of organism is, I do not believe that coexistence of organisms of different life styles is possible in same place. One will remove the 'other' one or the other. And I have made it very clear in my earlier posts that I believe that life originated on Earth even though it may had help from 'others'. I may be wrong and I would love to see the day when I am proven wrong but till then I am betting on Earth to have started life by itself.
Yes Prahant and Kenneth. I also have no any information of different life styles and agree that one can remove the other one. However bacterial life in black smokers can be recognized as independent of life in the surface of Earth. We cannnot image the result of meeting of different life styles. It is only S. Lem and S. Hawking caution.
Kenneth, Ok, I known it, but this life is independent of life from the surface. So, it is possible that organisms can survive in "islands" not accessible for other organisms. It is life of extremofiles as you known. It will be very interesting to investigate contact of these communities with "our world".
Yes, you are right. It is impossible. I can imagine that if panspermia is true, other lifestyle should come to Earth. What happened? It is the case of native Onas in S America? or siberian people rediscovered by Russian (in booth cases these people death after contact). I agree that different lifestyle cannot coexist.
Darwin's theory has a thermodynamic basis. Thermodynamics establishes a common genetic code in the universe. Biological diversity is a result of thermodynamic differences of environment! http://endeav.net/news/27-evolution.html
@Georgi, Thanks for the link but whatever the article proves or tries to prove...its all alien stuff to me. I am not able to comprehend how evolution of a species results in over all increase in entropy of the Universe (Multiverse!). And does extinction of species then decreases the entropy? Evolution can not and should not be tried to be understood just on the basis of development of a new species from an old species but it should also take into account extinction of a species and its net effect on the development of a species. Also if there are other types of lifestyles then the genetic code can not be be a common factor in our galaxy let alone the Universe or entire Multiverse, what ever the term means.
Dear Prashant,
Apparently you are not familiar with the concept of "entropy." Once again I am sending you the information about entropy.
Thank you.
Best,
Georgi
Misunderstandings in ideas about entropy
Many misunderstandings in understanding the problems of life and evolution from the standpoint of physics and physical chemistry are typically associated with misconceptions in understanding entropy. The term "entropy" coined Rudolf Clausius. According to his "model" of the world (universe), he presented a statement: "The energy of the world is constant. The entropy of the world tends to the maximum". Later this statement was chosen by JW Gibbs as an epigraph to the paper "On the Equilibrium of Heterogeneous Substances". These scientists have given this statement in relation to their model of the universe. This model corresponds to a simple isolated system of ideal gas, i.e. isolated system of ideal gas, energy and volume of this system are constant and in which only the work of expansion is performed. Entropy of such a system can only increase!
It should be noted that when we say on ideal model, which would correspond to the real universe, it would be necessary to accept the unreal assumption that any form of energy real universe will be transformed into thermal energy. Only in this case, also under additional unrealistic assumptions, the real universe "would turn" into the model of ideal system of Clausius - Gibbs.
However, lovers of science have applied representations on simple systems to systems of other types, in which the interactions takes place between particles of different nature (interactions of molecules or other objects of different hierarchies) and to systems which interact with the environment. Some scientists, who are not professionals in the relevant fields of knowledge, have not escaped such errors. This has led to unimaginable confusion. This has slowed down the development of science, more than on a century. There are thousands of publications in scientific journals and popular literature containing marked misunderstandings. To these were added incorrect ideas on the negentropy and on the dissipative structures in the living world.
The origin of life and its evolution can be easily explained from the standpoint of hierarchical near equilibrium thermodynamics of complex dynamic systems. This thermodynamics established on a solid foundation of equilibrium thermodynamics - thermodynamics of Rudolf Clausius, JW Gibbs and other great scientists.
http://www.membrana.ru/particle/17266
http://www.eoht.info/page/Entropy+%28misinterpretations%29 http://www.youtube.com/watch?v=CYr1G5TZO50
Detailing theories about the origin of life and evolution is presented in the new sites (Knol moved to Wordpress): Some work: http://gladyshevevolution.wordpress.com/
http://creatacad.org/?id=48&lng=eng
Hi Dr,
Interesting question. Have a look at the links below:
PANSPERMIA THEORY origin of life on Earth directed panspermia ...
www.panspermia-theory.com/
Panspermia theory: the origin of life on Earth and the transfer of life throughout the Universe. Popular variations are lithopanspermia and directed panspermia.
... ... ...
---- ... ... ...
Origin Of Life: The Panspermia Theory | Helix Magazine
https://helix.northwestern.edu/article/origin-life-panspermia-theory
Dec 2, 2008 - One possibility that hovers on this border is the panspermia theory, which suggests that life on Earth did not originate on our planet, but was ...
--------- ... ....
Introduction: More than Panspermia. by Brig Klyce - Cosmic Ancestry
www.panspermia.org/intro.htm
The first point, which deals with the origin of life on Earth, is known as panspermia — literally, "seeds everywhere." Its earliest recorded advocate was the Greek ...
------- ..... -----------
Panspermia theory claims life on Earth may have arrived here from ...
www.dailymail.co.uk/.../Are-ALIENS-Growing-support-panspermia-theory-life-Earth...
Aug 11, 2015 - Panspermia is not a new thoery – it was first proposed in 1871 - but it has more recently gathered fresh support as astronomers have ...
---------- ..... ---------- ..... ------------
Earth Life from Space? Tough Algae Suggests Panspermia Possibility
www.space.com › Search for Life
Sep 23, 2013 - Tough Algae Suggests Panspermia Possibility. An artist's illustration of a massive asteroid impact on earth. Some single-celled organisms may ...
__________________
Howdy all,
The first known mention of the "Panspermia" term was in the writings of the 5th century BC Greek philosopher Anaxagoras. Panspermia began to assume a more scientific form through the proposals of Jöns Jacob Berzelius (1834), Hermann E. Richter (1865), Kelvin (1871), Hermann von Helmholtz (1879) and finally reaching the level of a detailed hypothesis through the efforts of the Swedish chemist Svante Arrhenius (1903).
Fred Hoyle (1915–2001) and Chandra Wickramasinghe (born 1939) were influential proponents of panspermia. In 1974 they proposed the hypothesis that some dust in interstellar space was largely organic (containing carbon), which Wickramasinghe later proved to be correct. Hoyle and Wickramasinghe further contended that life forms continue to enter the Earth's atmosphere, and may be responsible for epidemic outbreaks, new diseases, and the genetic novelty necessary for macroevolution.
In an Origins Symposium presentation on April 7, 2009, physicist Stephen Hawking stated his opinion about what humans may find when venturing into space, such as the possibility of alien life through the theory of panspermia: "Life could spread from planet to planet or from stellar system to stellar system, carried on meteors."
Three series of astrobiology experiments have been conducted outside the International Space Station between 2008 and 2015 (EXPOSE) where a wide variety of biomolecules, microorganisms, and their spores were exposed to the solar flux and vacuum of space for about 1.5 years. Some organisms survived in an inactive state for considerable lengths of time, and those samples sheltered by simulated meteorite material provide experimental evidence for the likelihood of the hypothetical scenario of lithopanspermia.
Several simulations in laboratories and in low Earth orbit suggest that ejection, entry and impact is survivable for some simple organisms. In 2015, remains of biotic material were found in 4.1 billion-year-old rocks in Western Australia, when the young Earth was about 400 million years old. According to one of the researchers, "If life arose relatively quickly on Earth … then it could be common in the universe."
Alien or not, the 'seeds of life' developed to real living organisms on Earth in the Archean, because it is from that era and under those habitat conditions that life on Earth came into existence, mainly as prokaryotic cells (bacteria and cyanobacteria). After that evolution as described by Darwin for living prokaryotic cells diversified into organisms of all kind based on more complex cells, of eukaryotic nature, including some organelles of bacterial origin (mitochondria and chloroplasts). The eukaryotic era saw a split into three organism kingdoms, e.g. plants, animals and moulds. Humans developed from the animal kingdom in Africa some 200.000 years ago, and subsequently colonized the Earth completely, as we know it now. An interesting paper about the early Archean habitat and its radiation environment can be found at the following URL:
https://arxiv.org/ftp/astro-ph/papers/0702/0702529.pdf
Hence, is the question whether the 'seeds of life' were of alien or Earthly origin that important? It is my opinion that the step from the 'seeds of life' to life itself is largely uncharted. Still quite some work on the step of organic molecules (wherever they came from) to living cells is to be done.
Another issue is the nature of the 'seed of life'. OK, DNA, RNA, fatty acids, amino acids, proteins,.... Which of the seeds are resistant to the trip in space through the early atmosphere of the Earth, to seed life on Earth? How long would their journey through space take? Light-years from the closest planets? Or did they orginate in space on a comet or the like? How did that take place with gamma rays, X rays, UV rays. No way that DNA or RNA or the other molecules I cited could survive that when coming from Alien planets or even comets. Hence, what observational or experimental proof do we have that the 'seeds of life' were of alien origin? A lot of speculation and pretty minor amounts of hard evidence or hypothesis corroboration I figger.
Life on Earth from alien origin? The 'Panspermia' hypothesis is for sure not sure, that's for sure, only probable with a very low probability level.
Cheers
Frank
Hi Kenneth,
'Interesting' paper you published. By the way sorry for the expression and the lacking reference from my part to that paper. I was concentrating somewhat strongly on the doubtful 'alien' factor which might have 'seeded' the Earth into a 'living' planet.
Did you ever consider ethene (ethylene), produced by all living plants, moulds and bacteria as an ozone scavenger. It actually protects photosynthetic organisms against ozone in its deteriorating impact on the membrane systems in chloroplasts (stromae) thereby reducing/destroying photosynthetic capacity.
See URL: https://www.researchgate.net/publication/310506287_Can_ethylene_a_simple_gaseous_hydrocarbon_be_considered_as_a_plant_hormone_or_as_an_ozone_antagonist
Maybe 'interesting',
Cheers,
Frank
Article Can ethylene, a simple gaseous hydrocarbon, be considered as...
- Badges
- Science topic
- Similar topics
- Biological Science
- Molecular Biology