Heavens

GREENBELT, Md. – 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. These results were presented this morning at the 41st Lunar and Planetary Science Conference by Jacob Bleacher at NASA's Goddard Space Flight Center, Greenbelt, Md. Whether channels on Mars were formed by water or by lava has been debated for years, and the outcome is thought to influence the likelihood of finding life there.

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.

Scientists at the University of Rochester have discovered that the Earth's magnetic field 3.5 billion years ago was only half as strong as it is today, and that this weakness, coupled with a strong wind of energetic particles from the young Sun, likely stripped water from the early Earth's atmosphere.

The findings, presented in today's issue of Science, suggest that the magnetopause—the boundary where the Earth's magnetic field successfully deflects the Sun's incoming solar wind—was only half the distance from Earth it is today.

HOUSTON -- (March 5, 2010) – Components of the blood or hematopoietic system derive from stem cell subtypes rather than one single stem cell that gives rise to all the different kinds of blood cells equally, said scientists from Baylor College of Medicine (www.bcm.edu) in a report that appears in the current issue of the journal Cell Stem Cell (www.cell.com/cell-stem-cell/)

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

Located half a billion light-years from Earth, ESO 306-17, is a large, bright elliptical galaxy in the southern sky of a type known as a fossil group. Astronomers use this term to emphasise the isolated nature of these galaxies. However, are they like fossils — the last remnants of a once active community — or is it more sinister than that? Did ESO 306-17 gobble up its next-door neighbours?

CINCINNATI – The first comprehensive comparative effectiveness clinical trial of three widely used anti-seizure drugs for childhood absence epilepsy – the most common form of epilepsy in kids – has established an evidence-based approach for initial drug therapy.

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.

Propofol is safe for advanced endoscopic procedures with a low rate of sedation-related adverse events when administered by a trained professional, according to a new study in Clinical Gastroenterology and Hepatology, the official journal of the American Gastroenterological Association (AGA) Institute.

BOSTON--Older women who have had breast cancer surgery have a greater risk of the cancer returning if they delay their post-surgical radiation treatment, report Dana-Farber Cancer Institute scientists.

Stargazers all over the world are familiar with the distinctive profile of the constellation of Orion (the Hunter). Fewer know about the nebula NGC 1788, a subtle, hidden treasure just a few degrees away from the bright stars in Orion's belt.

ANN ARBOR, Mich. — Freezing a cancer kills it in its place, and also appears to generate an immune response that helps stop the cancer's spread, leading to improved survival rates over surgery, according to a new study in mice from researchers at the University of Michigan Comprehensive Cancer Center.

The longer women wait for radiotherapy after breast cancer surgery, the more chance there is of local recurrence, concludes a study published on bmj.com today.

The authors suggest that starting radiotherapy as soon as possible will minimise this risk.

Four to six weeks is generally accepted as a reasonable interval between cancer surgery and radiotherapy, but evidence on the effect of waiting times in patients with breast cancer is mixed.

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 completion of cryogenic polishing of the engineering development unit primary mirror segment is a hugely significant milestone for the Webb telescope project that demonstrates that our primary mirror segments can be completed on schedule while meeting the performance necessary for science," said Lee Feinberg, NASA Webb Optical Telescope Element Manager at NASA Goddard.