In February, the space agency announced the discovery of a star known as TRAPPIST-1 which was found to have seven planets orbiting it.
The newly discovered solar system, which is the closest to Earth ever found, has attracted the interest of alien hunters as three of its planets fall into the star’s habitable, or “goldilocks”, zone – the region around a host star where conditions are neither too hot nor too cold to support life.
Now, experts at the space institute say that TRAPPIST-1 could be up to 9.8 billion years old and a minimum of 5.4 billion years old – both of which are older than our solar system at 4.5 billion years old.
If enough time has passed for intelligent life to evolve here, the scientists say that if the planets are as habitable as they believe they are in the star system 40 light-years away, there is a decent chance that ET may be living there.
Nasa said in a statement: “If we want to know more about whether life could survive on a planet outside our solar system, it’s important to know the age of its star.
“Young stars have frequent releases of high-energy radiation called flares that can zap their planets’ surfaces. If the planets are newly formed, their orbits may also be unstable.
“On the other hand, planets orbiting older stars have survived the spate of youthful flares, but have also been exposed to the ravages of stellar radiation for a longer period of time.”
To find the age of TRAPPIST-1, Adam Burgasser, an astronomer at the University of California, San Diego, and Eric Mamajek, deputy program scientist for Nasa’s Exoplanet Exploration Program, used a standard checklist.
One indicator of the age of a star is the speed that it moves around the Milky Way – with older stars moving faster.
Another is the chemical composition of the star and how many flares it gives off.
The TRAPPIST-1 star has a mass which is about a tenth of our sun, which is another sign of its old age.
However, as the star could be almost 10 billion years old, the planets surrounding it would have undergone a bombardment of radiation, which reduces the chances of life being there, but does not completely eliminate the prospect.
Professor Burgasser said: “If there is life on these planets, I would speculate that it has to be hardy life because it has to be able to survive some potentially dire scenarios for billions of years.
“Our results really help constrain the evolution of the TRAPPIST-1 system, because the system has to have persisted for billions of years. This means the planets had to evolve together, otherwise the system would have fallen apart long ago.”