What’s really floating out in space?

Satellite imaging has revolutionized our knowledge of the Earth, with detailed images of nearly every street corner readily available online. But Planet Labs' Will Marshall says we can do better and go faster -- by getting smaller. He introduces his tiny satellites -- no bigger than 10 by 10 by 30 centimeters -- that, when launched in a cluster, provide high-res images of the entire planet, updated daily.

In this short talk, TED Fellow Sarah Parcak introduces the field of "space archaeology" -- using satellite images to search for clues to the lost sites of past civilizations.

Astronomers believe that every star in the galaxy has a planet, one fifth of which might harbor life. Only we haven't seen any of them -- yet. Jeremy Kasdin and his team are looking to change that with the design and engineering of an extraordinary piece of equipment: a flower petal-shaped "starshade" positioned 50,000 km from a telescope to enable imaging of planets about distant stars. It is, he says, the "coolest possible science."

Something massive, with roughly 1,000 times the area of Earth, is blocking the light coming from a distant star known as KIC 8462852, and nobody is quite sure what it is. As astronomer Tabetha Boyajian investigated this perplexing celestial object, a colleague suggested something unusual: Could it be an alien-built megastructure? Such an extraordinary idea would require extraordinary evidence. In this talk, Boyajian gives us a look at how scientists search for and test hypotheses when faced with the unknown.