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As long as you're up before dawn, set your sights on Jupiter as well. Now separated from the Sun by a healthy 50 degrees, the giant planet is an easy target for scrutiny. Daniel Costanzo says it may be hasty to describe the dark debris from last summer's comet crash as a conspicuous globe-girding belt. Using the historic 30-cm refractor at the U.S. Naval Observatory in Washington, Costanzo and other members of the National Capital Astronomers have observed instead what they call "interesting" and "boring" sides to Jupiter. The interesting half has a central-meridian longitude of roughly 320 degrees, corresponding to the region hit so obviously by fragments G, L, R, and Q. The boring one has a CML of about 140 degrees, near where pieces A and C struck.


The major skywatching event this week occurs on Monday morning, January 23rd, when the Moon occults the 1st-magnitude star Spica, and observers in the United States have front-row seats. The occultation will be seen first on the West Coast just before 10:00 Universal Time. But due the Moon's orbital motion it won't begin until about 11:10 UT in twilight on the East Coast. Just about that time Spica will be reappearing for observers in the West. Reappearance in the East occurs between about 11:50 and 12:10 UT. The Moon's phase is waning gibbous, so reappearance will be very dramatic along the dark lunar limb. Maps on page 84 in January's SKY & TELESCOPE show this all more clearly.


Two thousand astronomers met last week in Tucson, and they presented many important new results. One concerned supernovae, the deaths of massive stars. Theorists had figured that the collapse of a star's core and its subsequent "bounce" powered these violent events. But computer models always crashed before producing an explosion. Now teams led by Willy Benz and Adam Burrows have finally built computer models that explode like real stars. They succeeded by doing their calculations in two dimensions, something not possible before the advent of supercomputers. This allowed them to fully account for the energy supplied by tiny, massless particles called neutrinos, as well as departures from spherical symmetry, such as those caused by convection.


There is impressive evidence now for a massive black hole in the nucleus of M106, a galaxy in Canes Venatici. Japanese radio astronomers led by Makoto Miyoshi detected a thin ring of gas encircling the galaxy's core. The ring is only 1+ light-years across, and it is whirling around so fast -- 1,000 kilometers per second along its inner edge -- that it would fly apart unless held in place by a dense central object with a mass of some 40 million Suns. This object is almost certainly a massive black hole, because its inferred density is orders of magnitude higher than that of any known star cluster.

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