After Earth: Why, Where, How, And When We Might Leave Our Home Planet

[Num7]

Nice article about future possibilities for the human race leaving Earth and starting new civilizations in space. They talk about space missions, space elevators, propulsion systems and much more, it's a very interesting 4 pages article.

Earth won’t always be fit for occupation. We know that in two billion years or so, an expanding sun will boil away our oceans, leaving our home in the universe uninhabitable—unless, that is, we haven’t already been wiped out by the Andromeda galaxy, which is on a multibillion-year collision course with our Milky Way. Moreover, at least a third of the thousand mile-wide asteroids that hurtle across our orbital path will eventually crash into us, at a rate of about one every 300,000 years.

The first challenge is simply to escape the pull of Earth’s own gravity. “If you can get your ship into orbit, you’re halfway to anywhere,” the writer Robert Heinlein said. The space shuttle flew at around $450 million a trip, and today sending unmanned payloads into orbit will still set you back about $12,000 a pound, with much of the cost coming from the fuel burned in those first hundred miles.

But the national space program, despite tighter budgets, is also exploring the possibilities of life after Earth. Last spring, President Obama announced plans for manned missions to a near-Earth asteroid by 2025 and Mars by the mid-2030s. In October, Darpa, the Pentagon’s R&D branch, issued a press release announcing a joint project with Ames to study the possibility of creating a “100-year starship,” what they called “the first step in the next era of space exploration—a journey between the stars.”

Full article: http://www.popsci.com/science/artic...nd-when-we-might-leave-our-home-planet?page=2