The severity of the laboratory test was equivalent to an oblique collision with the rocky surface of the Earth - a comet coming in at an angle of less than 25 degrees from the horizon, rather than head on (perpendicular to the Earth's surface).

BBC: Comets could have seeded life on Earth

How often the Universe has planets truly like the earth - true earth twins, planets the size of the earth, rocky planets with a surface that supports liquid water - well, we don't have that number yet, but I'm optimistic we'll figure it out.

BBC: From counting to characterising exoplanets

Hidden 1, 000 feet beneath the surface of the Rocky Mountains lies the largest untapped oil reserve in the world.

FORBES: Obama Heads to Rio Sunday; Maximum Security Awaits

On Thursday, NASA released a sweeping color panorama of the planet's surface, showing the rocky, reddish desert surrounding it and the mountain it will explore in the coming months.

CNN: SHARE THIS

The art may appear on any writing surface even the rocky walls of cliffs but it is especially common on letters, scrolls, works of literature and fan coverings.

UNESCO: Culture

Female sturgeon don't become sexually mature until their 20s and spawn about every four years, so the spawning season, in which they surface from the depths to lay their eggs on rocky shores, is an extremely important time for the species.

WSJ: Standing Guard for the Sturgeon

Neutrons ejected from a watery surface move much more slowly than those from a rocky one, because the hydrogen nuclei in water are light enough for an exiting neutron to knock around much like one billiard ball hitting another a process that slows the neutron down.

ECONOMIST: Divining water

It's unlikely any aliens call Kepler-37b home: it's thought to be rocky, with no atmosphere, and hugs its sun in a 13-day orbit cycle, meaning surface temperature is terribly high.

ENGADGET: NASA's Kepler telescope spies smallest planet to date, no aliens