It is science fiction made fact: Astronomers have discovered two alien planets around the same star whose orbits come so close together that each rises in the night sky of its sister world like an exotic full moon.
The newfound planets are 1,200 light-years from Earth and an unprecedented find, researchers said. They differ greatly in size and composition but come within just 1.2 million miles (1.9 million kilometers) of each other, closer than any other pair of planets known, according to a new study.
[Full Story: Odd Alien Planets So Close Together They See 'Planetrise']
The mysterious structure of Stonehenge may have been built as a symbol of peace and unity, according to a new theory by British researchers.
During the monument's construction around 3000 B.C. to 2500 B.C., Britain's Neolithic people were becoming increasingly unified, said study leader Mike Parker Pearson of the University of Sheffield.
"There was a growing islandwide culture — the same styles of houses, pottery and other material forms were used from Orkney to the south coast," Parker Pearson said in a statement, referring to the Orkney Islands of northern Scotland. "This was very different to the regionalism of previous centuries."
[Full Story: Stonehenge a Monument to Unity, New Theory Suggests]
Some much-needed good news for sharks has come from Venezuela this week: The South American country announced it is banning shark finning in its waters and has established a new shark sanctuary.
The country became the last in the Americas to outlaw the practice of cutting off the fins of live sharks and tossing the animals back into the ocean to slowly die.
[Full Story: Venezuela Bans Shark Finning, Establishes Shark Sanctuary]
A close-up look at a grain of salt, a blue glacier against a pink sky and a map of sea-turtle tracks are among the winners of the 2012 Research as Art competition.
The competition, organized by Swansea University in Wales, is open to all Swansea researchers in any field who have a cool image to share. This year's entries included more than 100 images, from which judges picked 15 winners.
[Full Story: Intricate Salt Grain Wins 'Science as Art' Competition]
Icebergs melt in a Greenland Fjord as pink clouds reflect in the water. "It’s hard to describe the beauty and inspiration of the places in which we work," said photographer and glaciologist Tavi Murray." I am a scientist rather than an artist or photographer but a landscape like this talks directly to my soul."
A new U.S. spy satellite launched into orbit Wednesday (June 20), kicking off a clandestine national security mission for the National Reconnaissance Office.
The NROL-38 reconnaissance spacecraft lifted off at 8:28 a.m. EDT (1228 GMT) from Space Launch Complex-41 at Cape Canaveral Air Force Station in Florida, atop a United Launch Alliance (ULA) Atlas 5 rocket. It marked a milestone flight for the rocket company, a partnership between Lockheed Martin and Boeing.
[Full Story: Air Force Launches US Spy Satellite on Secret Mission]
Cheetahs and greyhounds have very similar running styles, but somehow the big cats leave their doggy rivals in the dust. Their secret: Cheetahs "switch gears" while running, striding more frequently at higher speeds, new research finds.
Greyhounds, on the other hand, seem to take the same number of strides per second at every speed.
[Full Story: The Secret to Cheetahs' Speedy Stride Found]
A crater on the moon that is a prime target for human exploration may be tantalizingly rich in ice, though researchers warn it could just as well hold none at all.
The scientists investigated Shackleton Crater, which sits almost directly on the moon's south pole. The crater, named after the Antarctic explorer Ernest Shackleton, is more than 12 miles wide (19 kilometers) and 2 miles deep (3 km) — about as deep as Earth's oceans.
[Full Story: Huge Moon Crater's Water Ice Supply Revealed]
Emperor penguins depend on the sea ice that rings the continent of Antarctic, so it's no surprise that global warming, which is expected to melt some of that ice, may be bad news for these flightless, 4-foot (1.2-meter) tall birds.
Since detailed information on most colonies is not available, the research focused on one well-studied colony of emperor penguins, at Terre Adélie in East Antarctica, to get an idea of what might happen to emperor penguins over the course of this century.
[Full Story: Melting Sea Ice Could Decimate Emperor Penguins]
Amidst clouds of dust and gas, new stars are born in the constellation of Scorpius. This glittering image is the best ever taken of the War and Peace Nebula, a star-forming region found in Scorpius. Created by the European Southern Observatory's Very Large Telescope, this photograph shows bright blue-white baby stars amidst gas clouds. A stream of dust through the nebula darkens the center of the image.
The War and Peace Nebula got its name because scientists on the Midcourse Space Experiment thought that one half of the nebula looked like a dove, while the other half looked like a skull. That effect isn't visible in this newest image.
In 1972, the crew of Apollo 17 took possibly the most famous picture of the Earth from space, which was dubbed "The Blue Marble." Since then, NASA has released many gorgeous images of our planet stitched together from satellite views. Usually, however, these Blue Marble images focus on the western or eastern hemisphere.
Not so this image, hereby dubbed "The White Marble." Using images from the Suomi NPP satellite, NASA put together this image of Earth from the top down. The icy Arctic appears amidst swirls of clouds, with Europe, Asia and northern Africa visible toward Earth's midsection.