Searching for Life – From Venus to the Outer Solar System | Alien life

It’s still one of this year’s most unexpected scientific discoveries. Much to their surprise, British scientists revealed last week They have uncovered strong evidence Phosphine – a toxic rancid gas produced by microbes – is present in Venus’ scorching, acid-filled atmosphere.

By rights, it simply should not be there. “All of the geological and photochemical methods that we can think of are much less productive than the phosphine production that we have seen,” said Professor Jane Graves, astronomer at Cardiff University, who led the team that made the discovery. This conclusion leaves scientists with the curious possibility that microbial activity – the main source of phosphine on Earth – may occur in the scorching acid clouds that blanket Venus.

Not surprisingly, news that Venus could have bugs made headlines. It also adds an alien new planetary focus for alien-hunting scientists on nearby planets – research that now leads them to strange and increasingly unexpected parts of the Solar System, from the frozen moons of Jupiter to Jupiter. Titan’s lakes filled with methane, Saturn’s largest moon.

While astronomers have yet to discover alien life forms, most are confident of someday succeeding, although their journey will take them through some interesting highs and some desperate lows. For example, in the late nineteenth century and most of the twentieth century, most astronomers were confident that one day they would find life in the solar system.

Two worlds seemed particularly promising: Mars And Venus, our closest neighboring planet. Telescopes showed that Venus was permanently surrounded by clouds – so this world was supposed to be covered in steamy jungles full of strange animal life. At the same time, notes Mars The proposed seasonal changes in vegetation were occurring there as some astronomers argued that they could actually see signs of the channels that were created on the planet.

“Then, in the early 1960s, we sent the first space probes to the planets and discovered that Mars was a dead, frozen desert and that Venus was a pit of hell,” said astrobiologist Louis Dartnell from the University of Westminster. “Prospects for finding alien life in the solar system are falling.”

In the case of Mars, the planet was found to have a painfully thin atmosphere and was hit by ultraviolet rays, while Venus was detected with a dense, extremely hot atmosphere of carbon dioxide lurking under dense clouds of sulfuric acid. It was very hot, and the lead would melt on its surface. Astronomers’ hopes of finding alien life on worlds near Earth have been dashed.

But in recent years, these hopes have begun to revive. On Earth, carbon-based organisms called radicals have been found living in some unusually hostile places: in nuclear waste. In highly acidic waters; In the subsea vents where temperatures and pressures reach enormous levels; And on panels mounted outside of the International Space Station, exposed to space vacuum for years.

Life is not quite fragile as it was previously assumed, it has been discovered. And if microbes can survive in the harsh conditions on Earth, maybe some of them can withstand the harsh environments of Mars or other hostile parts of the solar system.

Additionally, American interplanetary probes that are beginning to explore the more distant edges of the solar system have returned data that also raised hopes. He found that Jupiter has moons Which has deep underground oceans While it was discovered that Titan contains an atmosphere that contains organic chemicals, which are the building blocks of life, and has lakes of hydrocarbons such as ethane and methane on its surface.

For good measure, when American space engineers sent new missions to Mars, this revealed ancient streams and riverbeds through which water was flowing freely. Probably, Life evolved On the red planet and may still be stuck in underground pockets.

“It was a double whammy,” said Dartnell. “Planetary science has expanded and found new potential homes for life while biological science has shown that living things can live in environments much harsher than we previously thought. This has given astrobiologists like me renewed hope that we will have a chance to find life in other worlds in our system.” Solar “.

Scientists assert that these life forms – if they exist at all – will definitely not consist of intelligent beings capable of building channels or animals that inhabit strange jungles. Most of them expected it to come in the form of fairly simple organisms. However, their discovery would have enormous ramifications.

Nowadays, humans know only one world that supports life: ours. This may be a rare coincidence and that life appeared only once in the history of our galaxy – here on Earth. On the other hand, the opposite may be true. Life may be common and pervasive in the universe. And if astronomers find that life appeared independently in a second location in our solar system, this indicates that it is not rare at all and may have appeared on billions of planets in our galaxy.

But what are the most promising sites for finding life in our solar system? Where should we focus our search for aliens? Venus has just shown itself as a very unexpected new candidate for investigation. But where should we look?

Astronomers point to several other promising sites, each very different from the others – although the first site is direct: Mars. It was similar to Earth several billions of years ago and life probably appeared there around this time, just as it did on our planet. May persist in subterranean sediments.

It’s also a fairly accessible planet, and a fleet of spacecraft that includes the American Perseverance rover will soon visit, which is It is scheduled to land on Mars next year It will start collecting rocks to return to Earth sometime over the next decade. These samples will then be studied by scientists for fossil signals that show whether life once evolved on the red planet.

“As we persevere on their way to Mars, the prospect of collecting samples back to Earth has become really exciting, not only because we will have access to all the analytical capabilities that we absolutely want, but also because of the long-term benefits,” said the open university astrobiologist. Susan Schwenzer. “The Apollo samples from the Moon continue to be a rich source of research and allow us to discover new things decades after they first arrived in our labs. This applies equally to the Martian rocks that we bring back to Earth.”

By contrast, the frozen world of Europa is a moon Jupiter, It offers very different horizons to make references to life. Europa, completely covered in ice, is the softest body in the Solar System. It has neither mountains nor hills, only hills a few hundred meters high provide deflections along its polished surface. But beneath Europe’s glassy landscapes is an ocean of salt water, as space probes have discovered. “When you search for alien life, you search for water. Europe has got oceans from it, which makes it a very promising place to visit,” says Dartnell.

In 2024, the United States is set to launch the Europa Clipper, which will sweep the icy moon in 2030. This could then be followed by a separate landing mission that will look for signs of biological activity from materials that may have emerged from Europa. The underground ocean. However, the task will not be easy – the intense radiation field of nearby Jupiter poses certain problems, a point confirmed by astronomer Lee Fletcher of the University of Leicester.

“Organic chemicals and other compounds that are washed off the surface of Europa are constantly bombarded by radiation and this will destroy any living primitive material present. It will not last long and this will be difficult for any spacecraft trying to find out what is happening on Europe.”

By contrast, Enceladus, a small moon of SaturnIt provides an easier target and is more promising, according to some astronomers. The US space probe Cassini has revealed that it is actually spewing geysers – rich in salt and organic matter – from the underground ocean into space. If there were life forms out there, they should be easy to capture.

“It is simply the most promising place in the solar system for finding life,” said Professor Charles Kockell, an astrobiologist from the University of Edinburgh. There may be water and organic elements on Mars, but they are likely deep in Earth. But they flock to Enceladus into space. All we have to do is get rid of them. “

No missions to Enceladus have yet been identified, but scientists at the Jet Propulsion Laboratory in California are developing proposals – despite acknowledging that the trip there will be a long business. “It will take decades from the start of the mission to return the samples to Earth,” he added.

However, it is worth the wait even if we do not find any evidence of biological activity on Enceladus. Liquid water and organic matter are the two basic components of life and they are found in abundance there. However, if we find that life did not evolve there, despite the presence of water and organic matter, then that indicates that it must be very difficult to start moving. “

Saturn has another moon that also offers preservation hopes – Titan. It is wet, not with water but with liquid hydrocarbons like methane and ethane. “There are lakes of matter on Titan,” says Dartnell, “and although it is very cold there, there is a possibility that hydrocarbon chemistry leads to the evolution of life forms.” “It’s a wonderful possibility.”

This leaves Venus. In fact, most astronomers rule out the possibility of life thriving there – despite the discovery of phosphine in the atmosphere. These rotten puffs of gas are likely produced by some geochemical process currently unknown to science. “I doubt there are any life forms on Venus. It’s a very hostile place for that.” However, there are a lot of other promising places to look in the solar system.