Scientists believe they will be able spot of life on ‘thousands’ of planets within the next 20 years

Scientists looking for evidence of extraterrestrial life believe they will spot telltale signs on ‘thousands’ of planets within the next 20 years.

More and more powerful telescopes will be able to examine the atmospheres of planets hundreds of light-years away for evidence that we are not alone in the universe.

And if the experts find enough clues, they may even be able to formulate hypotheses about how extraterrestrial life compares to species found on Earth.

Cambridge scientist Emily Mitchell said she believed life was probably “quite common” throughout the cosmos and hopes to find the evidence. The evolutionary zoologist is investigating whether single-celled life developed on Earth and evolved into complex animals over billions of years by chance, or whether this process was repeated throughout the universe.

Signs of life on a planet are called ‘biosignatures’, and Dr Mitchell said: ‘We only have one biosignature, here on Earth. But if we have in ten or 20 years, as my optimistic colleagues suggest, thousands of biosignatures, we can begin to address [the question of whether we are alone in the cosmos].

“There’s this wonderful potential that if we have enough biosignatures, we can do the numbers and try to figure out how we compare to life on other planets.”

In 2021, NASA launched the James Webb Space Telescope, which has allowed scientists to see farther and in more detail than the 33-year-old Hubble telescope.

You can capture the light of stars passing through the atmosphere of a distant planet and analyze it for signs of chemicals generated by living organisms. The telescope has already given a detailed breakdown of the ‘air’ on a planet called Wasp-39B, some 700 light-years away.

NASA is planning “aggressive technology development” toward a possible future project called the Habitable Worlds Observatory, which will specifically examine the air of Earth-like “exoplanets” for signs that they may harbor life.

Dr Mitchell said that if oxygen, water and methane were all in one atmosphere, “you could say, ‘Yeah, it’s definitely life.'” Biological signatures could reveal whether the origin of life on Earth is just a happy accident or part of the fundamental nature of the universe.

More than 5,300 exoplanets have been discovered so far, the name given to planets outside our solar system, including one in another galaxy. Scientists say there are likely trillions in the Milky Way alone.

Dr. Mitchell shared her thoughts yesterday at the annual meeting of the American Association for the Advancement of Science in Washington. Also speaking at the event was Swiss astronomer Didier Queloz, a Cambridge scholar who won a Nobel Prize for discovering the first exoplanet in the 1990s.

NASA is planning “aggressive technology development” toward a possible future project called the Habitable Worlds Observatory, which will specifically examine the air of Earth-like “exoplanets” for signs that they might harbor life.

He said it would be “foolish to predict” when extraterrestrial life might be discovered, adding: “Maybe in a couple of years someone with the James Webb telescope will detect an atmosphere that will resemble Earth’s. Or maybe we’ll discover that most planets don’t have an atmosphere and realize that we’re very lucky on Earth.

But he also said that if we do find signs of extraterrestrial life, it may be very different to the carbon-based forms we have on Earth, as there may be more of a “chemical scenario conducive to life.”

Cambridge is collaborating with other universities on the research through a consortium called The Origins Federation. The group warned that “humanity has a long way to go before we fully understand the fundamentals of what life is and how it forms.” Professor Queloz, 57, added: ‘We are working on it. Hopefully, within my lifetime I’ll see something significant.