Science Daily

Distant galaxy clusters mysteriously stream at a million miles per hour along a path roughly centered on the southern constellations Centaurus and Hydra. A new study tracks this collective motion -- dubbed the "dark flow" -- to twice the distance originally reported.

While general relativity describes well the behavior of the solar system, Einstein's theory of gravity and spacetime has not been tested on cosmological scales. Now, a team has analyzed data on 70,000 galaxies to show that the theory is so far the best description of the universe, at least out to 3.5 billion light years from Earth. Specifically, theories without dark matter do not fit the observations.

Scientists have found evidence of a catastrophic event they believe was responsible for halting the birth of stars in a galaxy in the early universe. The researchers observed the massive galaxy as it would have appeared just three billion years after the Big Bang when the Universe was a quarter of its present age.

An international team of astronomers has shown that the two stars in the binary HM Cancri definitely revolve around each other in a mere 5.4 minutes. This makes HM Cancri the binary star with by far the shortest known orbital period. It is also the smallest known binary.

Shortly after the Moon formed, an asteroid smacked into its southern hemisphere and gouged out a truly enormous crater, the South Pole-Aitken basin, almost 1,500 miles across and more than five miles deep.

Planetary scientists have been puzzling for years over the honeycomb patterns and flat valleys with squiggly edges evident in radar images of Saturn's moon Titan. Now, working with a "volunteer researcher" who has put his own spin on data from NASA's Cassini spacecraft, they have found some recognizable analogies to a type of spectacular terrain on Earth known as karst topography.

Like a hard-driving athlete whose joints need help, the giant "Mars antenna" at NASA's Deep Space Network site in Goldstone, Calif. has begun major, delicate surgery. The operation on the historic 70-meter-wide (230-foot) antenna, which has received data and sent commands to deep space missions for over 40 years, will replace a portion of the hydrostatic bearing assembly. This assembly enables the antenna to rotate horizontally.

What if space held the key to producing alternative energy crops on Earth? That's what researchers are hoping to find in a new experiment on the International Space Station.

One of the pleasures of perusing ancient maps is locating regions so poorly explored that mapmakers warned of dragons and sea monsters. Now, astronomers using NASA's Fermi Gamma-ray Space Telescope find themselves in the same situation as cartographers of old. A new study of the ever-present fog of gamma rays from sources outside our galaxy shows that less than a third of the emission arises from what astronomers once considered the most likely suspects -- black-hole-powered jets from active galaxies.

The James Webb Space Telescope reached a mission-readiness landmark March 2, 2010 when its first primary mirror segment was cryo-polished to its required prescription as measured at operational cryogenic temperatures. This achievement sets the stage for a successful polishing process for the remaining 18 flight mirror segments.

Flowing lava can carve or build paths very much like the riverbeds and canyons etched by water, and this probably explains at least one of the meandering channels on the surface of Mars.

Extensive radar mapping of the middle-latitude region of northern Mars shows that thick masses of buried ice are quite common beneath protective coverings of rubble.

One year ago this week, NASA's Kepler mission soared into the dark night sky, leaving a bright glow in its wake as it began to search for other worlds like Earth.

ESA's Herschel Space Observatory has revealed the chemical fingerprints of potential life-enabling organic molecules in the Orion Nebula, a nearby stellar nursery in our Milky Way galaxy.

NASA's newest Mars orbiter, completing its fourth year at the Red Planet next week, has just passed a data-volume milestone unimaginable a generation ago and still difficult to fathom: 100 terabits.

The Cretaceous-Tertiary mass extinction, which wiped out the dinosaurs and more than half of species on Earth, was caused by an asteroid colliding with Earth and not massive volcanic activity, according to a comprehensive review of all the available evidence.

Mars Express encountered Phobos March 3, smoothly skimming past at just 67 km, the closest any artificial object has ever approached Mars' enigmatic moon. The data collected could help unlock the origin of not just Phobos but other "second generation" moons.

Astronomers have discovered a relic from the early universe -- a star that may have been among the second generation of stars to form after the Big Bang. Located in the dwarf galaxy Sculptor some 290,000 light-years away, the star has a remarkably similar chemical make-up to the Milky Way's oldest stars. Its presence supports the theory that our galaxy underwent a "cannibal" phase, growing to its current size by swallowing dwarf galaxies and other galactic building blocks.

New studies of ripples and dunes shaped by the winds on Mars testify to variability on that planet, identifying at least one place where ripples are actively migrating and another where the ripples have been stationary for 100,000 years or more.

Keeping an infrared telescope at very cold operating temperatures isn't an option, it's an absolute necessity. Serving as a radiation blocker, the Webb telescope sunshield is subjected to nearly 100,000 thermal watts of solar heat, and reduces that to one tenth of a watt on the cold side, a million to one reduction.