What Makes Our Neighborhood In Space So Wonderful

Its hard to think that life could only exist on this one, tiny planet in a vast and complicated universe. If you've ever wanted to get off this planet, like I have, you have probably taken a special interest in habitable planets. They are ones where carbon based life can survive and thrive relatively easily. But just how common are these planets, and what kind of requirements need to be met to support life?

In this SciShow video starring Hank Green, they explore what a habitable planet actually is and how likely it is that there are more and even better places for life in the universe. Some planets that are in our solar system, like Kepler-62E, could be habitable but are literally water worlds (no, not that Kevin Costner movie). On the other hand, planets like Mars have lost so much of their water that life couldn't be supported there either. All life on Earth is completely dependent on water, so a lack of or too much can throw everything off balance.

Another hurdle a planet has to overcome to be habitable is having just the right amount of sunlight. Our star is 90% larger than the average star, meaning there are a lot fewer planets that would receive adequate sunlight like we do. We receive just enough sun to grow our food and generate the right amount of heat for life. Smaller stars require a planet to be too close and at risk for one solar flare or seven hundred every day. There's also a pretty big risk of a moon that is too close to its planet, causing something Green calls being tidally locked. Half a planet would become so hot the water boils awaay and the other size would freeze, and any life on ground or in the water would die without sunlight.

The age of the star also makes a difference in if life can be supported on a planet. Our star is relatively young, and was created at the same time the planets were, so it's not at risk for completely destroying us, at least not yet. Green explains that other places in the galaxy are so cramped that there are constant threats to some planets of a nearby star exploding or just being exposed to too much radiation. Our area of the galaxy is safe from a lot of dying stars, so we are able to live without the constant risk of intense stellar radiation.

So where might actual habitable planets be in the universe? There are probably some in our galaxy, if anywhere, because the stars that are here are all about the same age. This means they have all the same access to heavy elements, like iron, that allowed for formation of our planet. With such a vast universe, there are infinite areas we haven't explored, it may just be a matter of time until we find another planet that is habitable. And hopefully before we destroy our own planet.