It remains one of the most unexpected scientific discoveries of the year. To their surprise, British scientists revealed last week They had found strong evidence Phosphine, a toxic gas produced by microorganisms, exists in Venus’ burning, acid-humid atmosphere.
By rights, it should not be there. “All the geological and photochemical routes we can think of are as productive as the phosphine we’m able to produce,” said Jane Greaves, an astronomer at Cardiff University. This conclusion gives scientists strange hope – the activity of microorganisms, the main source of phosphine on Earth, can occur in seasickness and acid clouds. Venus.
Not surprisingly, the news that there could be bugs on Venus created front page headlines. It also adds a strange new planetary focus to scientists hunting for aliens on nearby planets – now a search leads them to strange and unexpected parts of the Solar System, from Jupiter’s frozen moons Methane lakes on Titan, Saturn’s largest moon.
Although astronomers have yet to find aliens, most are confident of success one day, yet their journey will take them through some impressive heights and some disappointing low levels. For example, in the late nineteenth and early twentieth centuries, most astronomers were convinced that life would one day be found in the solar system.
Two worlds seemed particularly promising: Mars and Venus, the planets closest to us. Telescopes showed that Venus was permanently covered by clouds – so it was assumed that the world was covered in steam forests full of exotic animals. Meanwhile, observations Tuesday Some astronomers claim that traces of canals built on the planet can be traced to seasonal changes in flora.
“Then, in the early 1960s, we sent the first spacecraft to the planets and discovered that Mars was a frozen and dead desert and that Venus was a hell,” said Louis Dartnell, an astronomer at the University of Westminster. “The possibility of finding aliens in the solar system has taken a nosedive.”
In the case of Mars, the planet was found to have a painfully thin atmosphere and to be collapsing due to ultraviolet radiation, while Venus was found to have an atmosphere of dense and super-heated carbon dioxide beneath thick clouds of sulfuric acid. The place was very hot and the lead on its surface would melt. Astronomers’ hopes of finding extraterrestrials in near-Earth worlds were dashed.
But in recent years, these expectations have begun to unravel. On Earth, carbon-based organisms known as extromophiles have been found to inhabit some unusually hostile locations: in nuclear waste; In high acidity water; Through the ocean, where temperature and pressure reach a great extent; Also, bolting outside the International Space Station exposes the emptiness of space for years.
Life is not as weak as it once was, it was found. While microorganisms can survive the terrible conditions on Earth, some may endure the harsh atmosphere of Mars or other adverse parts of the solar system.
In addition, U.S. interplanetary probes, such as those exploring the far ends of the Solar System, provided promising data. Jupiter was found to have moons There are deep underground oceans When titan was discovered to have an atmosphere containing biochemicals and the building blocks of life, its surface contained the hydrocarbons ethane and methane.
As U.S. space engineers attempted to send new missions to Mars, ancient creeks and riverbanks were revealed, through which water once flowed freely. may be, Life has evolved The red planet may still be stuck in underground pockets.
“It was a double whammy,” Dartnell said. “As astronomy has evolved and new homes of life have been discovered, biology has shown that living things can survive in harsher environments than we previously thought. It renewed the hope that astronomers like me would have the opportunity to discover life in other worlds in our solar system. ”
These lifestyles – if they exist – will certainly not be the brainchild of intellectuals or alien jungle creatures, scientists say. Most people expect them to come in the form of very simple creatures. Their findings, however, will have far-reaching consequences.
At present, human beings only know about a world that supports life: our own. This could be a rare fluke and life has only once appeared in the history of our galaxy – here on Earth. On the other hand, the opposite may be true. Life in the universe can be normal and pervasive. If astronomers find that life appeared freely in the second place in our own solar system, this indicates that it is not uncommon and may have appeared on billions of planets in our galaxy.
What are the most promising places to find life in our own solar system? Where should our search for aliens be centered? Unexpectedly, Venus offered herself as the new candidate for the probe. But where else should we look?
Astronomers point to several other Promised Lands, each very different from the others – although the former is the opposite: Mars. It is very similar to Earth billions of years ago, and life may have appeared there at this time, as it did on our planet. This will last in underground deposits.
It is also a very easy desire to reach. The spacecraft, which includes the US robot rover Perseverance, will visit soon. It will land on Mars next year At some point in the next decade they will begin to collect rocks to return to Earth. Scientists will study these samples for fossil signals showing whether life has evolved on the red planet.
“With perseverance in the journey to Mars, the possibility of collecting return samples to Earth is really exciting because we have access to all the analytical capabilities we need, and because of the long-term benefits,” said Susan Schwenzer, an astronomer at the Open University. “The Apollo samples from the moon continue to be a rich resource for research, allowing us to discover new things decades after they first arrived in our laboratories. This also applies to the rocks on Mars that we bring back to Earth, ”she said.
In contrast, the frozen world of Europe, one of the major satellites Thursday, Offers very different possibilities for giving signs of life. Completely covered in ice, Europe is the most flexible body in the solar system. It has no mountains or hills, and only a few hundred meters high ridges deviate from its burnt surface. But below the glassy landscape of Europe there is an ocean of salt water, spacecraft have discovered. “When you look for aliens, you look for water. Europe has got oceans and this is a great place to visit, ”says Dartnell.
The U.S. will launch its Europa Clipper in 2024, which will conquer the iceberg in 2030. This is followed by a special lander mission, which looks for signs of biological activity from objects that may have emerged from Europe. Underground ocean. However, this is not an easy task – the intense radiation field of nearby Jupiter is causing particular problems, said Lee Fletcher, an astronomer at the University of Leicester.
“Washing the surface of Europe with biochemicals and other compounds is constantly attacked by radiation, which can destroy any existing primitive organisms. It won’t last long, and it will be tough for any spacecraft trying to figure out what’s going on in Europe. ”
In contrast, Enceladus, a small moon Sat., In the opinion of some astronomers, provides an easy and promising goal. The U.S. Cassini space probe revealed that it was emitting geysers of water rich in salt and organic matter from an underground ocean into space. If there are forms of life, they should be taken lightly.
“This is the most promising place 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 may be underground. But on Enceladus they are floating into space. All we have to do is get rid of them. ”
No mission to Enceladus has yet been scheduled, but scientists at the Jet Propulsion Laboratory in California are developing suggestions – although it has been acknowledged that a trip can be a long business. “It will take decades from the start of the mission to bring the samples back to Earth,” Kokel added.
“However, even if no evidence of biological activity at Enceladus is found, it remains to be seen. Liquid water and organic matter are two important components of life, and they thrive there. However, if we find that life has not evolved there despite the presence of water and living things, it indicates that it is very difficult to change dynamically. ”
Saturn has another moon that gives it hope of sustaining life – Titan. It is not in water, but is moistened with liquid hydrocarbons such as methane and ethane. “Titan has lakes, and although it’s very cold, hydrocarbon chemistry can cause life forms to evolve,” says Dartnell. “It’s an interesting prospect.”
It leaves Venus. In fact, most astronomers avoid the prospect of life there – even if phosphine is found in the atmosphere. Curved puffs of gas are produced by certain geochemical processes currently unknown to science. “I doubt there are any life forms on Venus. The space for that is very contradictory, ”Kokkal added. “Anyway, there are a lot of promising places to see in the solar system.”