Though black holes are often characterized as humongous gravity sinks, scientists believe there's a minimum mass requirement for any black hole in existence. They've got the requirements down pat by way of theoretical prediction only, but two able researchers from NASA finally pinpointed the smallest black hole to date. It could help them judge whether their estimates are accurate enough. More details at the full story.

Space may not be the final frontier just yet since we still have quite a few mysteries here on Earth, but it does have its own share of unexplained phenomena. One of these mysteries is the neutron star; the remains of a collapsed star. NASA is currently observing what may be a neutron star evolving before their very eyes. Details in the full article.

Engineers will soon install the first piece of  the GLAST Burst Monitor into the  Gamma-ray Large Area Space Telescope (GLAST), bringing the project another step closer to launch. Currently, it is scheduled to lift-off in little over a year.

GLAST will study the gamma ray bursts (GRBs) resulting when two neutron stars merger or a large star collapses. "GLAST will...open up a new window in the high energy range," says Charles Meegan, principal investigator of the GLAST Burst Monitor at NASA's Marshall Space Flight Center.

GRBs are just about the most distant phenomena scientists are able to observe. GLAST will need to meet some challenging goals that could rewrite the rules of physics. It will be able to study whether all light travels at the same speed in a vacuum. GLAST team members also hope to study how GRBs occur. "There hasn't really been a satisfactory explanation of the physics that goes on to get all this high energy radiation out in such a short amount of time," says Meegan. "We're hoping that measurements over a wider spectrum will contribute to the solution."

The mission may also test a theory that attempts to unify the laws of physics. Known as the "Unified Field Theory," proposes the existence of a fourth spatial dimension.

GLAST be launched aboard a Delta 2 Heavy rocket from Cape Canaveral Air in September 2007. The mission is designed to last five years, but the team hopes they can squeeze up to ten years out of the device.

Like "black holes", neutron stars are the dead cores of massive stars that exploded as supernovae. Their neutrons are packed together so tightly that a teaspoonful of the material would weigh several billion tons.

For years, science has held that matter might be transformed into exotic states in the dense interiors of neutron stars because of the kind of pressures to which matter is subjected. Some believed that neutrons would break down, freeing the individual sub-atomic particles - known as quarks - of which they are made.

Another theory suggests that such pressure might lead to a form of matter known as a Bose-Einstein condensate (BEC) in which neutrons do not break down into quarks. Their individual identities blur, however, as they start to behave as a single particle.

A new analysis of one of neutron stars now indicates that free quarks - never found by themselves in nature - in fact do not come from the cores of these massive bodies.

The old "exotic matter" theories, as they were known, have been disproved in a study by Feryal Ozel of the University of Arizona. An analysis of the mass and radius of a neutron star known as EXO 0748-676, found that it is probably made of ordinary neutrons.

Ozel calculated neutron star's radius to be 13.8 kilometers (about nine miles). Surprisingly, however, its mass came out to over twice that of the sun, suggesting that the star's neutrons are normal. As the mass of a neutron star increases, it becomes more and more rigid. Otherwise, it would collapse into a black hole under its own gravitational force. Most simulations of quark stars and BEC-containing neutron stars predict they would collapse into a black hole before reaching this great a mass.

"I think the physical measurement procedure is sound," says Frits Paerels of Columbia University in New York, US. "The number that comes out of it is interesting. The mass is surprisingly large."

Most neutron stars whose masses have been measured previously are no more than 1.4 to 1.5 times the mass of the Sun - but their actual sizes in terms of volume have been difficult determine, making the nature of the matter inside unclear.

Ozel says the fact that squishy, exotic states of matter do not seem to occur in a star this massive indicates that "exotic states" simply don't exist in these neutron stars.