In 2015, planet K2-18b was discovered by the Kepler Space Telescope, an observatory in space, during the “Second Light” K2 mission. It’s located around 120 light-years from Earth, in the constellation of Leo. Though it was one of over 1,200 other exoplanets discovered by the Kepler Telescope in the K2 mission, it has been a topic of discussion for astronomers all over the world. The question is, why?
Though it seems like K2-18b is insignificant, it holds extreme value for scientists all over the world. Not only does it orbit in its star’s habitable zone, but a recent study by researchers at University College London (UCL) found that planet K2-18b has water vapor in its atmosphere. This means that on an Earth-like planet, liquid water could exist.
But that’s exactly the problem. K2-18b has around 8 times the mass of Earth, which means the surface gravity of the planet would be much larger than that of Earth’s. In fact, researchers aren’t even sure if it has a rocky surface. Its distance from Earth is also a huge problem, as it is so far away that scientists can’t conceivably even send a probe to it. Even the star K2-18b is orbiting is also causing problems.
According to Rob Garner of NASA, “Given the high level of activity of its red dwarf star, K2-18b may be more hostile to life as we know it on Earth, as it is likely to be exposed to more high-energy radiation.”
Even if this one planet isn’t habitable, how about the thousands of others? Professor Tinetti of University College London says that even if there are others more habitable than K2-18b, we are still a long while away from colonizing or reaching one. “The Earth stands out in our own Solar System. It has oxygen, water, and ozone. But if we find all of that around a planet around a distant star we have to be cautious about saying it supports life.”
“This is why we need to understand not just a handful of planets in the galaxy but hundreds of them. And what we hope is that the habitable planets will stand out, that we will see a big difference between the planets that are habitable and the ones that are not,” Professor Tinetti adds.
Article by Christopher Jin of Takoma Park Middle School
Graphic by Katherine Hua of Robert Frost Middle School