- author, Ballab Ghosh
- stock, Science Correspondent – BBC News
Many space scientists have stopped to wonder if life exists elsewhere in the universe.
The question they ask is: When will we find out?
Many are optimistic that we will find signs of life on distant worlds within our lifetime, perhaps within the next few years.
A scientist leading a mission to Jupiter goes so far as to say it would be “surprising” if life didn’t exist on one of Jupiter’s icy moons.
NASA’s James Webb Space Telescope recently found disturbing signs of the possibility of life on a planet outside our solar system.
Many missions currently underway or soon to begin represent a new space race for the greatest scientific discovery ever.
“We live in an infinite universe, with an infinite number of stars and planets,” says Honorary Scottish Astronomer Professor Catherine Heymans.
He adds: “We now have the technology and the ability to answer the question of whether we are alone in the universe.”
Planets in the “Goldilocks Zone”.
Telescopes can now analyze the atmospheres of planets orbiting distant stars, looking for chemicals that can only be produced by life on Earth, at least.
The first flash of such a discovery was spotted earlier this month. A possible sign of gas produced by marine life on Earth has been found in the atmosphere of K2-18b, a planet eight times the size of Earth and 120 light-years away.
The planet is located in what space scientists call the “Goldilocks Zone,” a suitable distance from its star so that its surface temperature is neither too hot nor too cold, but well suited for the presence of liquid water. Necessary for life.
The team hopes to know within a year whether the disturbing signals they saw have been confirmed or disappeared.
If these signals are confirmed, Professor Niko Madhusudhan, of the University of Cambridge’s Institute of Astronomy, said, “It will fundamentally change the way we think about the search for life.”
He continued: “If we find signs of life on the first planet we study, it increases the likelihood that life is common in the universe.”
If his team doesn’t find signs of life on K2-18b, they have a list of 10 other planets, and possibly more after that. Finding none would “provide important insights into the potential for life on such planets,” he says.
His project is one of many ongoing or planned in the coming years to search for signs of life in the universe. Some search for planets in our solar system, while others search even deeper into space.
Although NASA’s James Webb Space Telescope is powerful, its capabilities are limited.
Planet Earth’s size and its proximity to the Sun are factors that allow life on it. But the James Webb Space Telescope can’t detect small distant planets like Earth or planets closer to their parent stars because of glare.
Therefore, NASA plans to build an Observatory of Habitable Worlds, which is scheduled to launch in the 2030s.
Using a high-tech sunshade, the planet reduces the light from the orbiting star. That means it can detect and model the atmospheres of planets like ours.
Later this decade, a giant telescope will also be available on the ground in the Chilean desert to see clear skies. At 39 meters in diameter, it has the largest mirror of any instrument ever built, so it can see more detail than its predecessors.
All three telescopes are used to analyze the atmosphere, a technique that chemists have used for hundreds of years to distinguish the chemicals within substances by the light they emit.
Its power is so high that it can be detected by a tiny speck of light from the atmosphere of a planet orbiting a star hundreds of light-years away.
Search near the ground
While some are looking at distant planets, others are focusing their search on the planets of our solar system, our planet’s backyard.
Europa, one of Jupiter’s icy moons, is the most likely to harbor life. It is a beautiful world with cracks like tiger stripes on its surface. Europa has an ocean beneath its icy surface, from which plumes of water vapor shoot out into space.
NASA’s Clipper mission and ESA’s Jupiter IC Moons Explorer (JUS) mission will arrive there in the early 2030s.
Shortly after Goss’ work was approved in 2012, BBC News asked Professor Michael Doherty, lead scientist on the European mission, whether he thought there was a chance of finding life. “It would be surprising if one of Jupiter’s icy moons didn’t have life,” he replied.
NASA is also sending a spacecraft called Dragonfly to land on one of Saturn’s moons, Titan. It’s a strange world with lakes and clouds made of carbon-rich chemicals. These chemicals, along with water, are believed to be essential elements for life.
Mars is currently considered too suitable for life, but astronomers believe the planet was once fertile, with a dense atmosphere and oceans capable of supporting life.
NASA’s Perseverance rover is currently collecting samples from the crater, which is thought to have been an ancient river delta. A separate mission in the 2030s will bring those rocks back to Earth and analyze possible microbial forms of simple life forms long gone.
Have you tried contact from aliens?
Some scientists consider this question far from the realm of science fiction, but the search for radio signals from alien worlds has continued for decades, not least by the Search for Extraterrestrial Intelligence (SETI).
The sprawling space is a big place to search, so searches have been uneventful so far.
But the ability of telescopes like the James Webb Space Telescope to pinpoint where extraterrestrial civilizations might be most likely means that SETI can now focus its search.
According to Dr. Natalie Cabrol, director of the Carl Sagan Center, this has injected new momentum into SETI’s study of life in the universe.
The company has upgraded its line of telescopes and now uses instruments to search for communications from distant planets from powerful laser pulses.
As a highly qualified astrophysicist, Dr. Cabrol understands why some scientists are skeptical of the search for SETI’s signals.
But chemical signatures from distant atmospheres, interesting readings from lunar flybys and microfossils from Mars are all open to interpretation, he says.
He adds that looking for the signal “may seem like a potentially distant goal compared to the various ways to detect signs of life. But it’s very obvious and within reach at any time.”
“Imagine receiving a signal that we can actually understand,” says Dr. Cabrol.
Thirty years ago, there was no evidence that planets orbited other stars. Now more than 5 thousand of them have been discovered, and astronomers and astronomers can study them in unprecedented detail.
According to Dr Subhajit Sarkar of Cardiff University, a member of the team studying K2-18b, all the elements are in place for a discovery that is more than just a spectacular scientific achievement.
He added: “If we find signs of life, it will be a revolution in science, and it will be a huge change in the way humanity sees itself and its place in the universe.”
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