Scientists say they have discovered two and possibly three planets orbiting a distant star, suggesting that other planetary systems can form under the most unfavorable conditions and probably are common throughout the universe.
The discovery was presented today as part of a smorgasbord of astronomical discoveries that could change a number of theories about the universe.
In a series of research papers in today's issue of the British science journal Nature, scientists also disclose that they have discovered mysterious bursts of powerful radiation from unknown objects that appear to be scattered around the universe.
The various findings, if confirmed by other scientists, could force the revision of some theories about the universe.
Last year British astronomers reported evidence of a single planet around a pulsar, known only by a number, PSR12829-10, but many scientists doubted that finding because no one had expected pulsars to have planets.
But now American scientists have come up with evidence that supports the British finding, and they take it a step further: they say they have discovered two, and possibly three, planets orbiting another pulsar, PSR1257+12, about 1,300 light years from Earth.
For decades scientists have searched for evidence of other planets around other stars, because the more planets there are the greater the chance of extraterrestrial life. So far, the only way to discover planets is to infer their existence from the behavior of their host star, because any star is so bright compared to its planets that the smaller bodies cannot be seen with optical telescopes.
Most stars with planets would appear to wobble when observed for long periods because the star and its planets would revolve around their common center of mass. So in recent years astronomers have sought stars that change their position slightly, because orbiting planets would be the most likely explanation for such a change.
Several potential planetary systems have been identified lately, but the most compelling evidence is perplexing because it suggests that planets have formed around super-dense, spinning stars called pulsars. Few experts expected planets to be found around pulsars, because those stars are believed to be formed in the violent explosion of a previous star.
Other scientists have been searching for the source of mysterious bursts of gamma rays. These extremely energetic bursts have been studied since they were accidentally discovered in 1967 by a satellite designed to monitor nuclear test ban violations. The bursts were thought to be coming from near the center of the Milky Way Galaxy.
It remained a mystery, because the center of the galaxy is so dusty that it cannot be penetrated by optical telescopes.
But the mystery has deepened considerably with the latest results from the Compton Gamma-Ray Observatory When the observatory looked for gamma ray bursts, it found them, but they were coming from everywhere, not just from the center of the galaxy.
"Everybody had believed they were coming from the galaxy," said Charles Meegan of NASA's Marshall Space Flight Center in Huntsville, Ala. "The big shocker is, they are not (coming just from the galaxy.)"