Is there life on Venus?

For years, astronomers have been searching for other planets that support life. These efforts were made based on terrestrial telescopes and even spacecraft, to identify clues about the state of the worlds thousands of light years away.

But all searches are based on a widely accepted background - that the planets must be in the 'living area ', a narrow band around other stars on the surface of an act. Refining around is not too hot, not too cold and especially with liquid water. Recently, some astronomers have proposed: expanding the search farther than Earth-like planets, including strange planets, from planetary Arrakis-like crystals in telecoms Dune (Sand Hill) idea, there is virtually no liquid water, to giant gas-filled planets.

'We all know that water is essential for life ,' said MIT Institute of Physics and Physics professor Sara Seager, who authored an article published in Sciences magazine. searching for life in planets outside the solar system - which is not in the 'living area . ' Sara Seager said: 'If an extrasolar planet has liquid water on the surface, it has life. Planets very different from Earth can have water on the surface, with the same temperature as the surface of the Earth. "

There is no definition of the exact distance of the 'living area' , because it depends on the size and brightness of the stars (the bigger and brighter the stars, the more 'the area of ​​life' is around). it will be bigger). This concept has been considered many times since it was first introduced in the 1960s. With stars similar to our Sun, the 'living area' is now assumed to lie between 0.99 and 1.70 astronomical units (about 148 million km to 255 million km), in which the Earth is close to the inner edge. Seager and other scientists say that the search for life outside the universe should be expanded in both internal and external directions to find a solar system similar to ours, between about 0.5 and 10 singles. astronomical taste.

The surface of Venus, photographed by NASA's Magellan spacecraft in 1991.

According to this new proposal, only a few extrasolar planets at a distance are added to the 'brightest' list of about 60 to 70 planets in the 'living area' - beyond 2,700 candidates. which scientists have identified so far. Despite being small, expanding the 'living area' will also increase the chances of finding a planet in the universe that exists in life forms. The proposal to extend the concept of 'living area' still retains the element of water on the face as a mandatory requirement for life to exist, but they also turn to common knowledge about the conditions can lead to liquid water. Even planets farther or farther away from their stars than the distance between Earth and the Sun can still exist, said Seager and other scientists.

For planets located close to their parent star, such as Venus and the Sun, it will fall into a dry state, most of the surface is desert - meaning it won't be there. Much water vapor in the atmosphere, which is mainly hot air. According to Seager, 'steam is the most serious greenhouse gas on Earth. Because a planet with little water vapor will not be too hot if it is closer to its parent than Earth and the Sun. " According to this hypothesis, life may have existed more than 1 billion years ago on Venus. But, because the amount of steam makes it too hot when the intensity of the Sun's light gradually increases, and perhaps that heat causes life to die.

Other scientists are not sure about that theory. David Catling, a University of Washington professor of planetary and space biology, said: 'I think a planet similar to Dune is a perfect idea. However, I suspect that a planet with most dry surfaces will have a density of biomarkers that you can find from a place like Earth with a surface covered by the ocean. " Catling points out. that the idea of ​​a planet like Arrakis that supports life is given in a 2011 report by US and Japanese scientists, and Professor Seager's new article references this document with many talents. Other data, including some that support the further expansion of 'living areas' to Saturn, or planets with hydrogen-rich atmospheres.

Saturn photos taken by Voyager 2 spacecraft.

Seager said: 'Hydro can make planets of Earth-equivalent orbits too hot, but it also expands' areas of life' because it makes these planets hotter than their stars. " But Catling disagrees, he argues, that water microorganisms on Earth consume hydrogen gas, remove it from the atmosphere. So if a planet has a lot of hydrogen in the bulb. The atmosphere, there will be no water microorganisms present, so life may not exist.

One of the scientists, however, proposed a new concept of 'living areas' that said extrasolar planets with hydrogen-rich atmospheres are bright candidates for life's viability. including the planets 'wandering' (planetary rogue), floating alone in interstellar space without any mother stars near to 'heat' it. " Planets with a high hydrogen atmosphere may still have life, even if they no longer circulate around their parent stars ," said James Kasting, professor of geology at the University of Pennsylvania . Therefore, the 'living area' can be anywhere! But this will lead to further debate about the concept of "areas of life".

Graphic image of the "wandering" planet floating alone in interstellar space.

Kasting also adds that we should keep the standard concept of 'living areas' in mind until there are new telescopes hunting the planet. 'It helps us to make the criteria for how much and how much to create telescopes to be able to search for planets with life .' But Kasting also supports the feasibility of open concept. wide 'area of ​​life' once we have new telescopes. 'We all know that life does not originate from the Earth. So if we can find planets similar to the Left Land and seeking evidence of life, surely we will get a satisfactory answer ' to the question of whether we are alone in this vast universe.