It’s thought that the galaxy is teeming with planets–like, 100 billion of them. The Kepler telescope has spotted nearly 1,900 of these planets, but we have yet to catch a glimpse of one that’s still developing.
If a massive comet struck the Earth, the oceans would boil and the air would catch fire (don’t worry, this isn’t about to happen). But to alien astronomers studying our planet from afar, humanity’s brutal demise would look like nothing more than a faint flicker of light. If we could detect such impacts on distant worlds, we might learn a lot about their star systems.
Some planets that are now small, hot, and rocky may have started off as icy giants like Neptune. Orbiting too close to their stars, their gassy shells boiled off until all that’s left is a rocky core. That’s what scientists have thought for a long time, anyway. Now, for the first time, they’ve spotted a small exoplanet that seems to be in the process of evaporating. The boiling atmosphere of the Neptune-sized GJ 436b is creating a tail that’s nine million miles long and about two million miles wide.