It remains the most unexpected scientific discovery of the year. To their surprise, British scientists revealed last week that they had found strong evidence of phosphine – a toxic, waste gas produced by bacteria – in Venus’ burning, acid-debris environment.
By right, it just shouldn’t be there. Leading astronomer Professor Jane Graves of Cardiff University, who made the discovery, said, “All the geological and photochemical substances we can think of are far more productive in creating the phosphine we’ve seen,” and concludes with the bizarre possibility of scientists. Leaves that microbial activity – the main source of phosphine on Earth – can occur in dry, isolating, acidic clouds.
Not surprisingly, the news that there might be bugs on Venus made headlines on the first page. This has added the focus of a bizarre new planet for scientists orbiting alien life on nearby planets – a search that is now taking them from Jupiter’s frozen moon to Titan’s methane-laden lakes to the increasingly strange and unexpected parts of the solar system, Saturn’s largest moon.
Although astronomers have yet to identify alien lifeforms, most are confident of success one day, although their journey has taken them through some worrying heights and some frustrations. In the late nineteenth and early twentieth centuries, for example, most astronomers were confident that they would one day find life in the solar system.
And two Earths seemed particularly promising: Mars and Venus, the neighbors of our nearest planet. Telescopes showed that Venus was permanently scattered in the clouds – so it was assumed that it was covered in a steamy forest filled with exotic animal life. At the same time, observations of Mars have shown that there are seasonal changes in vegetation, and some astronomers have argued that they will actually see signs of canals built on the planet.
“Then, in the early 1960s, we sent our first space probe to the planets and discovered that Mars was icy, dead desert and Venus was a hellhole,” said Louis Dartnell, an astronomer at the University of Westminster. “The prospect of finding alien life in the solar system has been a concern.”
In the case of Mars, the planet’s painful thin atmosphere was found and struck by ultraviolet radiation, while Venus was exposed to a dense, heated atmosphere of carbon dioxide hidden beneath a thick cloud of sulfuric acid. The place was so hot, the lead would melt on its surface. Astronomers hope to find alien life on Earth near Earth.
In recent years, however, these hopes have begun to fade. On Earth, carbon-based organisms astrophils have been found to live in some remarkably hostile places: in nuclear waste; In high acidic water; In the lowlands of the subsoil where temperatures and pressures reach abundant; And the panels are bolted to the outside of the International Space Station and come into contact with emptiness year after year.
Life is not as fragile as once thought, it has been discovered. And if germs could survive in deadly conditions on Earth, perhaps some would be able to withstand the harsh environment of Mars or other hostile parts of the solar system.
Also, U.S. interplanetary probes that began exploring the remote edges of the solar system have returned information that also raised hopes. Jupiter was discovered to have the deepest underground oceans on Jupiter when Titan was discovered to have biochemical environments, building blocks of life, and lakes of hydrocarbons of ethane and methane on its surface.
For better measurement, when U.S. astronauts were able to send new missions to Mars, they revealed ancient Christ and the river bed through which water once flowed unhindered. Presumably, life evolved on the Red Planet and may still be stuck in underground pockets.
“It was a double hate,” Dartnell said. “Planetary science has expanded and found new potential homes for life while biological science has shown that organisms can survive in a much harsher environment than we previously imagined. This has given astronomers like me renewed hope that we have the potential to find life in other worlds in our solar system. ”
These forms of life – if they exist at all – will certainly not be created by intelligent humans or animals living in exotic forests capable of creating canals, scientists say. Most expect they will come in the form of fairly simple creatures. Yet there have been many setbacks to their discovery.
At present, man knows only one world that supports life: our own. It could be that this is a rare fluke and life only appeared on Earth once in the history of our galaxy. On the other hand, the opposite may be true. Life in cosmic life can be conventional and extensive. And if astronomers knew that life had appeared individually in the second position of our own solar system, it would suggest that it is not at all uncommon and that billions of planets in our galaxy could be raised.
But what are the most promising locations for finding life in our own solar system? Where should we search for aliens? Venus has just presented itself as a highly unexpected new candidate for the investigation. But where else should we meet?
Astronomers point to a few more promising positions, quite different from each other – although the first is straightforward: Mars. It was similar to Earth billions of years ago, and life can be present here just as it did on our planet. It can be fixed in underground deposits.
It is also a planet that is easy enough to reach and will soon be visited by a fleet of spacecraft, including the US robot Rover Perseverance, which is scheduled to land on Mars next year and begin collecting rocks back to Earth at some point. Over the next decade, these samples will be studied by scientists for fossil signals that show whether life once evolved on the red planet.
“With perseverance on the way to Mars, the prospect of collecting samples to return to Earth is becoming really exciting, not only because we want access to all the analytical powers we want, but also because of the long-term benefits,” said Open University astronomer Susan Schweinzer. “Apollo samples from the moon continue to be a rich resource for research and allow us to discover new things decades after entering our laboratory. And it will be equally true for the rocks on Tuesday that we will bring back to Earth, ”he said.
In contrast, Jupiter’s main moon, Europe’s icy life offers very different possibilities to provide signs of life. Completely covered in ice, Europa is the smoothest body in the solar system. It has no hills or ridges, only elevated parts a few hundred meters high providing deviations with its burning surface. But beneath the glass landscape of Europe lies a sea of salt water, space explorations have discovered. “When you are looking for an alien life, you are looking for water. And Europa has got its sea, which has made it a very promising place to visit, ”Dartnell said.
The United States is set to launch its Europa Clipper in 2024, which will overtake the Ice Moon in 2030. A separate lander mission could then be followed that would search for signs of biological activity from material that could be of concern to Europa. Emphasized by Fletcher.
“The biochemicals and other compounds washed up on the surface of Europe are regularly bombarded by radiation and this is going to damage any primitive living material. It won’t live long and it’s going to be tough for any spacecraft trying to figure out what’s going on in Europe. “
Conversely, according to some astronomers, Saturn’s tiny moon Enceladus provides a simpler and more promising target. The U.S. Cassini space investigation has revealed that it is actually releasing water geysers – rich in salt and organic matter – from the subterranean ocean to space. If there are life forms, they should be easy to pick.
“This is one of the most promising places in the solar system to find life,” said Professor Charles Cockel, an astronomer at the University of Edinburgh. “Mars may have water and organic matter, but it is probably deeper underground.” But at Enceladus they are coming out into space. All we have to do is clean them up. “
No mission schedule has yet been set at Ensedas, but scientists at the Jet Propulsion Laboratory in California are developing proposals – although it has been acknowledged that there will be a long journey. “It will take decades from the start of the mission to actually get samples to Earth,” Kokel added.
“However, even if we do not find any evidence of biological activity in Enceladus, it would be appropriate to wait. Liquid water and organic matter are the two main components of life and they are abundant there. However, if we find that life has not evolved despite the presence of water and biological presence there, which suggests that it can be a very difficult subject to move. “
Saturn has another moon right that also hopes to sustain life. Titan. It is soaked in water, not with water but with liquid hydrocarbons such as methane and ethane. “Titan’s stuff has a lake and even if it is out in the winter, there is a possibility that hydrocarbon chemistry could lead to the evolution of life forms,” Dartnell said. “It’s an interesting prospect.”
And that leaves Venus. In fact, despite the discovery of phosphine in the atmosphere by most astronomers – the possibility of a rich life is left there. “I doubt if Venus has any life form. This is a very unfavorable place for him, “added Kokkel. “However, there are many more, more promising places to see in the solar system.”