There's a new gold rush heating up, but the hunt isn't for oil, gas or tech stocks - it's for asteroids. There are more than 10,000 near-Earth asteroids shooting by at any given moment, and many of them contain valuable resources like water, platinum and iron. While water and iron don't seem worthy of a gold rush by Earth standards, their value skyrockets due to their scarcity in space and the challenge of extracting them. If private companies can figure out a sustainable way to mine and sell these cosmic assets, they could make a killing in the new space economy and help fuel the next stage of galactic pursuits in the process. Already, private companies are betting big on the potential of asteroid mining and working hard to get there first. Japan launched its own asteroid mining operation last year. Serial entrepreneur and X Prize founder Peter Diamandis believes the first trillionaire will be made in space. That's right: trillionaire. If that's hard to imagine, just take a look at the value of one asteroid compared to what we normally think of as expensive or high-value: What exactly makes asteroids so valuable? While water is abundant on Earth, in space, it becomes a multi-purpose commodity. It can fuel rockets, sustain potential life on other planets and shield astronauts from harmful radiation. Asteroids also contain large quantities of platinum and its sister minerals, which are incredibly rare on Earth and can be sold for a hefty profit.