Panspermia (1)

PANSPERMIA 1 Roberto Bartali

An artist representation of panspermia. From: http://www.daviddarling.info/encyclopedia/P/pan spermia.html

Life is on my opinion something common in the universe and not only it is common, but it is almost of the same kind, carbon based. Every star, no matter of its mass, produce the basic chemical elements for life: C,N,O, these, combined with the Hydrogen, that is the most abundant element in the Universe, make possible the complex molecule that sustain life. If the star is more massive than the Sun, it can produce much more elements during its life on the Main Sequence, normally the first 26. If the star is even more massive, when explodes as a supernova, produce all other elements. This way the Universe is filled with the basic elements for the life generation and

sustaining. As Carl Sagan said in his Cosmos series “we are all made of stardust” and “all living things (plants, animals and humans) are all cousins”. I agree with him. All living creatures have a common ancestor and this ancestor came from somewhere in space. It is simply unbelievable, for me, to think that we are alone, as a class mate of mine said: “…The very essence of the universe should be to produce not just living organisms but conscious life forms (of which we are one example) to admire its beauty and design…The universe needs conscious receptors just as these need the universe for their very own existence and thriving…”. I think he was right, the Universe

is filled of life and there is no sense for just one planet filled with living species. It is simply absurd and I do not know why most people are so arrogant to believe in The Green Bank Radiotelescope inWest Virginia, USA. the human being as the best and the From: http://www.gb.nrao.edu/ unique form of civilized life in the immensity of the Universe. When we search for ET (Extra Terrestrial) life we have to take two ways: 1 search for intelligent and technological life, 2 search for life in general. Each way has some drawbacks. For the first, we have to receive some kind of signals with logical contents, or receive an answer for some message we are sending out.

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For the second, it is more difficult, because we have to send space probes to planets, satellites or comets (like the Nasa Stardust mission) and check for micro organism. But life can be in a stage of evolution very different from place to place. Also it can be completely destroyed and all we can find are fossils. This is not as difficult as appears, because an impact of a sufficient massive object like a comet or a little asteroid, may borrow any form of life on a planet. We have various examples here on the Earth (220 and 65 million years ago, an impact ended most of the life, I am speaking about the Australian and Mexican impacts respectively). But the principal problem is: if life is common, from where it came from? Well, I think, but I can not offer any proof for that, the molecular clouds that are capable Composite image of the Comet Wild 2, made by the Stardust NASA mission. The aim of the mission was to collect and return to Earth some particles of the comet tail. From: http://stardust.jpl.nasa.gov

to form a star and its planetary system, contains all the necessary elements to form amino acids and other molecule capable to start some kind of living cell. Which way living organism can travel from a planetary system to another or simply from

some place to another in the same system? The answer is, for me, simple: Comets, but, again I can not offer any proof. Which way the living organisms survive during the long journey from a remote place in the planetary system and colonize other planets? The temperature and the condition when the comet is far from the central star are very extreme, (very low temperature), also they are extreme in the opposite way when the comet reach the inner part of its orbit (perihelion), because the temperature and the radiation are both very intense. The comet is just a little piece of rock covered by ice (almost water ice), when it reach a distance of 300 million km or more, from the star, in the Solar System case the orbit of Mars and the main asteroid belt, it starts to evaporate the surface ice and the solar wind blow it away. If the living organisms are occulted in the interior of the comet, they are safe from the low temperature and they may be in a kind of hibernation stage, (we see many animals that slow down their metabolic functions during winter, because it is difficult to find Comet Hale Bopp foods, and, they wake up every spring). From: So, when the temperature condition is favorable, they http://www.usr.toscana.it/WS_FIT wake up and they are ejected from the comet and uses F015006/studenti/altrimondi/vita/or igini5.htm the dust particle as a space ship, eventually they land on some planet, satellite or asteroid.

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If the conditions, in the new place, are favorable, they can multiply and evolve. But if the planet contains living bodies there are two possibilities: 1 there are a massive destruction of life 2 there are an interaction with the inhabitants. The first case occurs because the immunological system of the inhabitants is not able to decipher the genetic code of the invading cell and die rapidly. The second case is when the interaction is capable of generating a mutation, so a new specie can appears. After many million years of evolution, we can see the development of tools and rapidly the beginning of the technological age. Again, we know now many extremophylies, they are microbes who love to live in condition of temperature, radiation, atmosphere, where a “normal” plant or animal may die in few minutes. We are looking for extraterrestrial life in nearest planets and satellites and we expect to find micro organism, but maybe we can not find any, because the environment, there, is, today, not able to sustain life. Mars was a place plenty of water, but now it is a big desert, If we do not take care of our environment, in a few thousands of years, we destroy all the possibility of life on our planet and the Earth may ends as a big desert too. At the time when Frank Drake, formulated his equation, nobody knows any exoplanet, today we know many of them, and haw many planets are hidden? Infra-Red (IR) terrestrial and space telescopes can now show us a lot of small cold stars (like brown dwarfs), we actually knows just a little number of objects outside our planet, we are just discovering objects outside Pluto orbit, so I think that the 90% (in number of objects, not their mass) of the Galaxy is invisible to us due to the low technological skills False color image of the rock named “Earart Rock” by the Opprtunity robot on the surface of the planet Mars. The Red Planet was once covered of water, so, sometimes we will find fossilized rest of life. From: http://marsrovers.jpl.nasa.gov/gallery/press/opportunity/200410 07a.html

of the human kind.

Now in conclusion (in my own opinion), life is present in a very great number of places. Here, on Earth, the technology to make space ships to travel to other planets and build giant radiotelescopes for interplanetary communications is only 50 years old. But: life is present on this planet from at least 3500 millions years ago, so the last 50 years are only the 0.00000143% of the total life time. Also, only a few countries (less than 20) in the world may send satellites to outer planets (not very efficiently yet because many of them get lost), they represent a very few percent of the total, +/- 10%; speaking in terms of number of people, they represent a much less quantity.

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So, finding life in general and, intelligent life in particular, is just matter of time because if life starts at the same time everywhere, the evolution needs 3500 million years to reach our present state of knowledge. But waiting for 100 or 500 years are nothing compared to the whole time of the life history, so we have to search and wait an enormous quantity of time (compared to our living time) but one instant compared to the age of the life on the Earth.

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