Life could be discovered on other planets within just 20 years, scientists believe

One of the world’s leading planetary scientists has claimed that astronomers are standing on a “great threshold” of space exploration that could see evidence of extra-terrestrial life being discovered in the next 20 years.

Life beyond the Earth seems “inevitable” given the immensity of the universe, according to Dr Sara Seager, and in the coming decades, chemical fingerprints of life written in the atmospheres of planets orbiting nearby stars could be found by the next generation of space telescopes.

Writing in the Proceedings of the National Academy of Sciences journal, Dr Seager, from the Massachusetts Institute of Technology, said: “We can say with certainty that, for the first time in human history, we are finally on the verge of being able to search for signs of life beyond our Solar System around the nearest hundreds of stars.”

Astronomers now know that statistically every star in our galaxy, the Milky Way, should have at least one planet, and small rocky worlds like the Earth are common.

“Our own galaxy has 100 billion stars and our universe has upwards of 100 billion galaxies – making the chance for life elsewhere seem inevitable based on sheer probability,” said Dr Seager.

In the next two decades, a handful of “potentially habitable” exoplanets will have been found with atmospheres that can be studied in detail by sophisticated space telescopes. Nasa’s James Webb Space Telescope due to be launched in 2018, will analyse the atmospheres of dozens of “super-Earths” – rocky planets larger than Earth – including several that could harbour life.