New exoplanet discoveries have been piling up fast in recent years, and whenever astronomers confirm the existence of another planet there’s always an immediate interest in whether or not that planet could support life. For many newly-discovered worlds the answer is a firm “no.” They’re either too hot, too cold, or they’re just big balls of gas, but when a rocky world is discovered to be just the right distance from its star the possibility of life remains.
A new research paper published in Astronomy & Astrophysics Letters explains how even some planets in the so-called “Goldilocks zone” of their parent stars can be doomed to harsh fate with no possibility of supporting life as we know it.
For a planet to support life as we know it on Earth, it needs to have an atmosphere of some kind. Many young planets are believed to form atmospheres early on, which sounds like great news for anyone hoping that mankind finds extraterrestrial life out in the cosmos some day, but there’s a bit catch.
Young planets are often in orbit around young star, and scientists are beginning to realize now more than ever just how difficult it is for a planet to hang onto its atmosphere in the face of an active young star.
The paper explains that abundant M-dwarf type stars, which are considered the most plentiful in our neck of the woods, may make life very difficult for the planets that orbit them. Unlike stars like our own Sun, M-dwarf type stars go through particularly active streaks at a young age, spewing elevated amounts of X-ray and ultraviolet radiation for billions of years.
It’s that radiation that can rapidly strip a nearby planet of its atmosphere. In fact, even a planet with an Earth-like atmosphere could completely lose it within a little as one million years if it were orbiting a particularly active young star. This isn’t great news for alien hunters, but it does tell us a good deal about how unique Earth truly is, and it could help narrow down our search for extraterrestrial life in the future.
