The Ring Garden, a finalist in this year's Land Art Generator Initiative competition.

California is still suffering from a severe drought, but one design firm may have an answer: a massive solar-powered floating pipe that can desalinize 1.5 billion gallons of water a year. Another option is a gigantic sun-powered Ring Garden that blends water purification with sustainable agriculture. In other energy news, Costa Rica is on a roll - the nation has managed to power itself entirely with renewable electricity for 113 days and counting. And in Chile, the price of solar power has plummeted to half the cost of coal.

This week astronomers announced what could be the biggest story of the century: an earth-like planet is orbiting the star nearest to our sun, just over 4 light years away. In other science and tech news, Egyptian researchers have discovered a way to grow forests in the desert using sewage. Scientists at the University of Warsaw created a tiny robot caterpillar that's able to push objects ten times its size. And Japan announced that it wants to make the 2020 Olympic medals from recycled smartphones.