(10 of 12)
One proposed candidate to provide the needed matter is the neutrino -- if it has mass and exists in the universe in such profusion that it could fill the bill. But 1987A may yet pour cold water on that idea: by coming in ahead of the light and in such short bursts, the neutrinos must have been traveling at or nearly at the speed of light. If they moved at the speed of light, according to Einstein, they have no mass. And if they traveled a bit more slowly and have mass, says Bahcall, that mass "is probably so small that the neutrino can't contribute noticeably to the problem." In other words, if the universe eventually crunches, it will almost certainly not be the neutrinos' fault.
Another report in last week's Nature, while not dealing with 1987A, provided further insight into Type II supernovas. A group led by Chemist Edward Anders and Physicist Roy Lewis, both of the University of Chicago, revealed that they had discovered an abundance of submicroscopic diamonds in a meteorite that fell in Mexico in 1969. While the impact of a meteor slamming into the earth creates enough pressure to crystallize carbon into diamonds, the tiny samples found by the Chicago team apparently resulted from an ancient supernova. The evidence: they contained atomic forms of the gas xenon different from the kind found on earth or detected in the sun.
The diamonds, Anders suggests, came from red supergiant stars that threw off their outer coats, forming a gas shell. As the star's shell expanded outward and cooled, the carbon in it condensed and crystallized, forming diamonds. Later, when the star exploded, it created xenon that shot from the star's outer layers and caught up with the diamonds. "It's like the tortoise and hare," says Anders. "The xenon atoms overtake the diamonds and shoot right through them, becoming very securely locked up."
If shock waves from an ancient supernova sparked the creation of the sun and planets, Anders concludes, "it's very likely that the material from which our solar system was formed was contaminated with these diamonds. The diamonds on earth may well be a mixture of those loaded with xenon and those without it."
Still, it was the big diamond in the sky, 1987A, that was getting most of the attention last week. While the supernova shines in southern hemisphere skies, most of the world's astronomers are in the northern half of the world, and they are scrambling to find ways of viewing 1987A directly rather than vicariously through the reports of others. Says Laurence Peterson, of NASA's astrophysics division, host of the brainstorming meeting at Goddard: "Hundreds of scientists are working on ideas." One proposal: temporarily base NASA's Kuiper Airborne Observatory, which is aboard a customized Lockheed C-141 StarLifter, south of the equator. Flying at 40,000 ft., above most of the murk of the atmosphere, the Kuiper can turn its 36-in. infrared telescope on the supernova. It can be equipped with nearly a dozen other instruments that will enable scientists to determine with precision how cool the supernova's envelope is becoming, and how the dust from the blown envelope is condensing.