Alien life forms can be seen on television and in cinemas, but so far she has never been seen in real space around us. And we are not talking about green men or Klingons with wrinkled faces, but about ordinary microbial life forms, living or dead.
Despite the absence of detected protoplasm, even skeptical academics admit that life outside the Earth can exist. At least that's what Seth Shostak, senior astronomer of the SETI project, which searches for extraterrestrial civilizations, thinks so. Evidence is expected to be found within a generation of humans. Scientists support their point of view with many astronomical facts that were unknown even a generation ago.
In particular, thanks in large part to the success of NASA's Kepler space telescope, we can now confidently assert that the universe is filled with worlds close to ours; over the past two decades, more than a thousand planets orbiting various stars have been discovered.
It seems that most stars generally have planets, that is, in our Milky Way galaxy alone, the existence of a trillion small bodies is implied.
Deeper analysis of Keppler's data suggests that at least one in five stars may have a planet similar to Earth in size and average temperatures. Such worlds can be covered with atmospheres and have liquid water on their surface. In other words, theoretically, the Milky Way could be filled with tens of billions of Earth's relatives.
It is difficult to admit that all these worlds are sterile, and the circumstance that created us, as well as all the flora and fauna of our planet, was a miracle. As a rule, all miracles are sooner or later refuted by science. Basically, there are only three ways to confirm or deny the existence of extraterrestrial life, and they all depend on complex and expensive experiments.
First, life can be found by cosmic standards very close to us. Indeed, real attempts are being made to do this, for example, on Mars. But so far, most searches have been indirect: deploying a rover system, whose job is to find the best places to explore the Red Planet, searching for fossilized or living microorganisms under a sterile surface. In Shostak's view, these are not attempts to find life - they are attempts to find places where life can be found. There is almost no progress.
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Without a doubt, Mars remains a prime candidate for the title of guardian of extraterrestrial life. Nevertheless, some experts are betting on the moons of Saturn and Jupiter. At least five of these moons appear to have habitable environments, mostly liquid water, and in the case of Titan, natural gas.
The types of life that might best develop on these moons are microscopic. Their presence can be detected in several ways, ranging from routine flights, missions, observing vapors from natural geysers to sending sophisticated drilling rigs that penetrate tens of kilometers of ice and reach sub-ice seas.
Unfortunately, most of the reconnaissance vehicles that can do all this are still in the project stage. Progress has been slow, mainly due to weak funding.
Another way to search for evidence of the existence of extraterrestrial life is to analyze the atmospheres of planets orbiting other stars. This is done using spectroscopy, an approach that allows researchers to find out the composition of the atmosphere many light years away.
In practice, this is quite difficult to do, since the planets are dim, but the stars around which celestial bodies revolve are very bright. Multi-element orbital telescopes and giant light blockers installed in space can contribute to the improvement of the "visual" abilities of astronomers. Engineers can build such devices over the next decades, but only if there is money for such projects.
A third approach aimed at finding life beyond Earth is to seek intelligent life by listening to radio signals, looking for laser beams or heat radiation. This search may be facilitated by powerful receivers, but funding is also a limiting factor here.
It is believed that in 2015 NASA has allocated a budget of $ 2.5 billion (more than 90 billion rubles) for planetary science, astrophysics and the continuation of work on the new James Webb Space Telescope. They seem to cover all of the search categories described above. But this is significantly less than one-thousandth of the total US federal budget, Shostak notes.
The funds allocated for the SETI project, which deals with the third approach, are a thousand times less. So it boils down to this: we don't know for sure if there is life in space around the earth, but the circumstances of the universe certainly suggest that this is a plausible idea. Confirmation of this is just a matter of funding.