Asteroid mining is about more than just heading up into space and bringing back a rock full of platinum - you actually need to land something on just the right asteroid.
Tagged With dispatches from aaas
There are many definitions of an Earth-like exoplanet. Some say it's a planet that orbits a star at just the right distance for liquid water to exist on its surface. Some say it's a rocky planet, such as ours. But determining if an exoplanet is truly habitable requires actually figuring out what's on the planet.