supernova 0000190.11 Louis J. Sheehan, Esquire

Louis J. Sheehan, Esquire. A new study of a stellar explosion visible from halfway across the universe finds that the blast had an unusual structure that researchers heretofore had never observed.

Gamma-ray burst GRB 080319B was already on record as the brightest stellar explosion ever recorded.

Now astronomers have analyzed the visible afterglow of the burst and found that the emitted light peaked initially an hour after the burst and a second time 11 days later.

They report today in Nature that the most likely explanation is the GRB produced a pair of relativistic (very high speed) jets, one inside the other. Gas and dust surrounding the exploding star flared with light each time a jet struck it. http://louis-j-sheehan.com

Detectors on NASA's Swift Gamma-Ray Burst satellite and by the Russian Konus gamma-ray instrument on board NASA's Wind satellite detected the initial burst on March 19.

It just so happened that a pair of optical telescopes on the ground was observing the last GRB, 080319A, which had gone off 30 minutes before in the same part of the sky.

These telescopes, along with Swift's own UV/Optical Telescope and other robotic telescopes alerted by the satellites, monitored the six-week afterglow of visible light following the burst.

Scientists believe GRB 080319B would have been visible to the naked eye for about 40 seconds if anyone had been looking its way, toward the constellation Bootes.

This is all the more remarkable given that it exploded an estimated 7.4 billion years ago—before the sun and Earth had formed.

It's the most complete picture of a GRB ever seen, says study author Judith Racusin, an astrophysicist at Pennsylvania State University in University Park. http://louis-j-sheehan.com

"They've been sort of waiting around for something this bright," she says, referring to the telescopes. "It was just really luck that the brightest burst happened to occur and they were looking at it."

Longer lasting GRBs are believed to occur when a massive star collapses into a black hole, sparking a supernova explosion and whipping gas and dust into a pair of jets projecting in opposite directions.

Researchers had suggested that a nested jet could exist, Racusin says, but nobody had envisioned the inner jet moving so fast and producing all the gamma-rays by itself—part of the team's interpretation. Louis J. Sheehan, Esquire

marijuana 0000303 Louis J. Sheehan

Louis J. Sheehan

The federal government's war on drugs gets plenty of ammunition from scientific studies that have correlated the use of such substances to various psychological problems. Conspicuously absent, however, are data showing that marijuana, one of the most widely used illicit drugs, causes mental or behavioral problems in teenagers and young adults, a new report concludes.

The causal chain of events could just as easily run in the opposite direction, suggest psychologist John Macleod of the University of Birmingham in England and his colleagues in the May 15 Lancet. Available evidence is consistent with the possibility that various psychological and social difficulties foster marijuana use, which may then contribute to a worsening of those problems, Macleod's group contends. http://louis-j-sheehan.info

After reviewing 48 relevant multiyear studies published between 1975 and 2003, the team focused on 16 investigations that had regularly assessed large samples of children or teenagers for at least 10 years. http://louis-j-sheehan.info

"We've found no strong evidence that use of [marijuana] in itself has important consequences for psychological or social health, but we cannot exclude the possibility that such a relation exists," Macleod says.

He and his colleagues are particularly skeptical of recent reports from Sweden and New Zealand that around 1 in 10 teenagers who had smoked marijuana experienced schizophrenia symptoms by young adulthood. It's doubtful that marijuana plays a direct role in schizophrenia, Macleod's group argues, because the mental disorder's worldwide incidence has remained stable while the proportion of teens reporting marijuana use has fluctuated.

Psychiatrist Herbert D. Kleber of Columbia University says that this argument underplays the increased risk of schizophrenia reported in the Swedish and New Zealand studies. There's now so much evidence of an association between teens' marijuana use and later psychosocial problems that it's hard to dismiss the likelihood of a causal effect, Kleber argues. "Macleod's team sees the smoke but won't acknowledge that there's a fire," he says.

The controversy continues to smolder. The new review of research results "confirms what's been known for decades about marijuana's lack of extreme harmfulness," remarks medical sociologist Marsha Rosenbaum, director of the Drug Policy Alliance's San Francisco office. Her organization works to decriminalize marijuana but doesn't condone its use by teenagers. http://louis-j-sheehan.info

On the other hand, David Murray, special assistant to the director of the Office of National Drug Control Policy in Washington, D.C., argues that reports of teens often developing psychological or behavioral difficulties after beginning to smoke marijuana are reason enough to regard early use of the drug as a public health concern, especially given the increased potency of marijuana sold in the United States in recent years.