Word: asteroidal
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...with flying debris, and they say it is only a matter of time before another large celestial object bears down on Earth. Reminders of that potential for disaster occur frequently. Early in January, for example, NASA released several radar images of the 6.4-km-long (4-mile) dumbbell-shaped asteroid Toutatis taken when it sped within 3.5 million km (2.2 million miles) of Earth -- a hairbreadth by astronomical standards. And while the warning that the 10-km-wide (6-mile) Comet Swift-Tuttle might slam into Earth in 2126 has now been retracted, it briefly caused genuine concern among many...
Proceedings at the interception workshop were tumultuous. But there was general agreement about the basic strategy: detect the threatening object and dispatch a warhead-tipped rocket to intercept it and explode, nudging it into a new orbit that would carry it safely past Earth. For a small asteroid detected years and many orbits before its destined collision, the solution would be straightforward. "You apply some modest impulse to it at its perihelion, or closest point to the sun, using conventional explosives," explains Gregory Canavan, a senior scientist at Los Alamos National Laboratory. "The slight deflection that results will amplify during...
More likely than not, a threatening asteroid of that size would be spotted earlier. But so-called long-period comets (those making their first appearance or returning at intervals of greater than 200 years) are another matter. Appearing without warning as they streak in from the outer reaches of the solar system, they usually become visible to astronomers only from a few months to two years before passing Earth. Should one suddenly appear on a collision course, traveling as fast as 217,000 km/h (135,000 m.p.h.) relative to Earth, defenders would not have the luxury of years of observation...
...interlopers. They simply "did not want to talk about very large amounts of energy," says Canavan. "And therefore they wanted to ignore the problem." Some suggested heatedly, in leaks to the press, that pro-nuclear Star Wars scientists, frustrated by the down-sizing of their projects, were using the asteroid and comet threat as an excuse for revitalizing their jobs...
...crashing comet, wayward black hole or alien spacecraft level the forest around Tunguska, Siberia, in 1908? None of the above. A computer model by NASA scientists revealed that the likely culprit was a stony asteroid -- 30 m (100 ft.) in diameter -- that exploded...