Image by NASA/JPL-Caltech
Researchers have found that the TRAPPIST-1 system could be twice the age of our solar system—a finding that has implications on the search for life outside of Earth.
A recent study shows that star TRAPPIST-1 and its seven “Earth-like” planets are between 5.4 to 9.8 billion years old. Our solar system, in comparison, is just under 4.6 billion years old. The findings also suggest that the TRAPPIST-1 planets came into existence together, because otherwise, the system would have long fallen apart.
TRAPPIST-1 is a star that lies about 40 light years away from Earth. Earlier this year, astronomers announced the discovery of the seven TRAPPIST-1 planets, which are roughly the size of Earth. Three of these planets lie in the habitable zone—a zone in which there's a possibility of liquid water existing on the surface of a planet. Where there's water, there may be life.
The TRAPPIST-1 planets are close in size to Earth. [Image by NASA/JPL-Caltech]
At first, scientists thought that the TRAPPIST-1 system was about 500 million years old. This, as it turned out, was a huge underestimation. The youngest that the TRAPPIST-1 system could be is 5.4 million years old, which is still almost a billion years older than our own solar system. Astronomers were able to calculate how old the system was by analyzing TRAPPIST-1's chemical composition, the frequency of its flares, and how quickly it moves through the Milky Way. The oldest that the system can be is about 9.8 billion years old, which may seem quite ancient. However, dwarf stars like TRAPPIST-1 have trillions of years to shine.
So what does age have to do with possible life on the TRAPPIST-1 planets?
For one thing, it indicates that life has had quite a long time to thrive on a planet or more. Some scientists believe that the TRAPPIST-1 planets have had more than enough time for complex life forms to develop. However, they have also had billions of years' worth of radiation from their host star. This radiation may have stripped away the atmosphere from the planets a long time ago. Without an atmosphere, liquid water will not be able to form on the surface. This means that the existence of life on these planets may not actually be possible.
Liquid water on the surface of the TRAPPIST-1 planets may not be possible. [Image by NASA/JPL-Caltech[
However, this isn't the first set back that we've encountered when it comes to the possibility that the TRAPPIST-1 planets may host life. For one thing, the planets are tidally locked to their host star. This means that one side of the planets forever faces the star. One side is perpetually day, while the other side is perpetually night. One side is very hot, while the other is very cold.
A thick atmosphere can make a tidally locked planet more livable, since the atmosphere can distribute heat around the planet. However, if radiation has stripped the planets' atmospheres away, the distribution of heat would not be possible.
The study, while informative, isn't conclusive. The findings aren't enough for scientists to conclude whether or not the planets really are habitable. However, the study is a significant addition to a growing body of knowledge about the TRAPPIST-1 system.
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