Obama clarifies alien comments after telling podcast ‘they’re real’

– If you ask scientists hunting for extraterrestrial life what kind of alien planets they’re most excited to study, a lot of them will probably give you the same answer: hycean worlds. Hycean worlds are planets completely covered by an ocean of liquid water. In fact, that’s half the name. The “cean” in hycean comes from ocean. As far as we know, liquid water is absolutely necessary for any life to develop. Someday, we might be proven wrong in that thought, but for now, liquid water remains the elixir of life and the number-one indicator of a habitable planet. The other critical trait of a hycean planet is its atmosphere. The “hy” in hycean stands for hydrogen, on account of hycean worlds having thick, hydrogen-rich atmospheres. While hydrogen might not be what you would expect scientists to be looking for when hunting down atmospheres that could foster life, considering our own nitrogen and oxygen-dominated situation, experts have proven over the years that simple organisms like e. coli bacteria can survive in hydrogen-dominated environments. So two big check marks on the list of what to search for when hunting down a habitable planet: liquid water and a livable atmosphere. But there’s a third aspect of hycean worlds that makes them extra enticing for scientists. They have the potential to be pretty big. The size of a planet isn’t the biggest indicator of its habitability, but it does have an impact on whether or not we can see that planet. Through no fault of their own, exoplanet scientists are extremely biased towards spotting larger planets, on account of everything just being so far away. It’s easier to see an elephant from 100 yards away than it is to see a mouse, and the thickness of the atmosphere factors into this size bonus too. When looking for signs of life, the best tool scientists have in their toolkit is spectroscopy. They can look at the way light filters through the atmosphere of a planet, see what chemicals are in that atmosphere, and decide if any of them could be signs of life. More light can filter through thicker atmospheres, making it easier for scientists to see what’s in there. Now, all of this comes with a huge caveat. As of right now, hycean worlds are still theoretical. We can’t actually see exoplanets in enough detail to know for certain if one is completely covered by an ocean or not. We can make pretty educated guesses using atmospheric analysis and orbital mechanics, and we’ve seen candidates we’re pretty sure fit the bill, but we can’t be positive just yet. Guess we’ll just have to keep looking.