NYTimes
By DENNIS OVERBYE
Published: October 5, 2005

With a screech of high-energy radiation brighter than a million billion suns, a pair of stars in a faraway galaxy collided two billion years ago and disappeared into a black hole.

That cataclysm, recorded by a battery of telescopes and NASA satellites on July 9, has provided scientists with the answer to the last remaining piece of 35-year-old astronomical mystery: the origin of explosions that sporadically shower outer space with gamma rays, the most energetic and deadly form of electromagnetic radiation.

"This is the real deal," said Donald Lamb of the University of Chicago, a co-author of one of four papers by an international cast of astronomers being published on Thursday in the journal Nature...
.....
Gamma ray bursts come in two types: long and short. Two years ago, astronomers were able to trace the long bursts, which last from two seconds up to a minute or more, to certain kinds of supernova explosions in very distant galaxies.

But about 10 percent of the bursts are shorter, often lasting less than a second, and have thus been harder to study. Theorists have speculated that they could originate in double-star systems where a pair of neutrons stars or a neutron star and a black hole spiral ever tighter in a death dance toward merger and oblivion.

But on May 9, by homing in on the X-ray afterglow of a short burst, a team using NASA's Swift satellite was able to trace a 70-millisecond burst to the vicinity of an elliptical galaxy about 2.9 billion light-years away in the constellation Coma Berenices. This was significant, because such galaxies lack the massive young stars that give rise to the more violent core-collapse explosions...
...

Experts Unlock Clues to Spread of 1918 Flu Virus

The 1918 influenza virus, the cause of one of history's most deadly epidemics, has been reconstructed and found to be a bird flu that jumped directly to humans, two teams of federal and university scientists announced yesterday...

...

The scientists painstakingly traced the genetic sequence, synthesized the virus using tools of molecular biology, and infected mice and human lung cells with it in a secure laboratory at the Centers for Disease Control and Prevention in Atlanta. The research is being published in the journals Nature and Science.

The findings, the scientists say, reveal a small number of genetic changes that may explain why this virus was so lethal. It is significantly different from flu viruses that caused the more recent pandemics of 1957 and 1968. Those viruses were not bird flu viruses but instead were human flu viruses that picked up a few genetic elements of bird flu.

The research also confirms the legitimacy of worries about the bird flu viruses, called H5N1, that are emerging in Asia. Since 1997, bird flocks in 11 countries have been decimated by flu outbreaks. So far nearly all the people infected - more than 100, including more than 60 who died - contracted the sickness directly from birds. However, there has been little transmission between people....
.....

...