Ghostly galaxies composed almost entirely of dark matter speckle the universe. Unlike normal galaxies, these extreme systems contain very few stars and are almost devoid of gas. Most of the luminous matter, so common in most galaxies, has been stripped away, leaving behind a dark matter shadow. These intriguing galaxies-known as dwarf spheroidals-are so faint that, although researchers believe they exist throughout the universe, only those relatively close to Earth have ever been observed.

While scholars have put forth various assessments for the location of the Second Temple in Jerusalem, a Hebrew University of Jerusalem professor says that archaeological remains that have so far been ignored by scholars point to the exact location, which is in a spot that differs from prevailing opinion.

The location identified by Prof. Joseph Patrich of the Hebrew University Institute of Archaeology places the Temple and its corresponding courtyards, chambers and gates in a more southeasterly and diagonal frame of reference than have earlier scholars.

A robotic therapy device may help people regain strength and normal use of affected hands long after a stroke, according to a University of California, Irvine study.

Stroke patients with impaired hand use reported improved ability to grasp and release objects after therapy sessions using the Hand-Wrist Assisting Robotic Device (HOWARD). Each patient had at least moderate residual weakness and reduced function of the right hand, although the affected hands were neither totally paralyzed nor unable to feel.

This NASA Hubble Space Telescope image shows the colorful "last hurrah" of a star like our Sun. The star is ending its life by casting off its outer layers of gas, which formed a cocoon around the star's remaining core. Ultraviolet light from the dying star then makes the material glow. The burned-out star, called a white dwarf, appears as a white dot in the center. Our Milky Way Galaxy is littered with these stellar relics, called planetary nebulae. Hubble's Wide Field Planetary Camera 2 captured this image of planetary nebula NGC 2440 on Feb. 6, 2007.

A University of Calgary archaeologist has found the first prehistoric evidence of chimpanzee technology, adding credence to the theory that some of humanity's behavioral hallmarks were actually inherited by both humans and great apes from a common ancestor.

Dr. Julio Mercader, one of the few archaeologists in the world who studies the material culture of great apes, especially chimpanzees, uncovered stone 'hammers' last year in the Taï rainforest of Africa's Côte D'Ivoire (Ivory Coast) that date back 4,300 years.

Human nerve stem cells transplanted into rats' damaged spinal cords have survived, grown and in some cases connected with the rats' own spinal cord cells in a Johns Hopkins laboratory, overturning the long-held notion that spinal cords won't allow nerve repair.

A report on the experiments will be published online this week at PLoS Medicine and "establishes a new doctrine for regenerative neuroscience," says Vassilis Koliatsos, M.D., associate professor of neuropathology at Johns Hopkins.