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 Credit: Galileo Project, JPL, NASA |
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Aug 06, 2004 The spacecraft Galileo, on its journey to Jupiter, snapped photos of asteroids Gaspra in 1991 and Ida in 1993 (photo above). These were the first two asteroids seen close up, revealing unexpected features. They were more heavily cratered than expected. Gaspra had two arrays of overlapping grooves. Some of Ida's craters were much larger than expected. But the biggest surprise was that 52-km (36 mile) Ida is orbited by a moon, Dactyl, an egg-shaped body about 1.6 km (1 mile) in its longest dimension. Since then, other asteroids with moons have been discovered. The Electric Universe offers a different origin and history of the asteroids from conventional astronomy, so this is an opportunity to compare actual features of the asteroids with the expectations of the two theories. Conventionally, the asteroids are thought to be condensations that should have accreted into a planet when the rest of the planets were formed but failed to do so because the pull of their giant next-door-neighbor, Jupiter, interfered. Craters accumulated one at a time by random collisions. Grooves were caused by large collisions that nearly tore the asteroid apart. The Electric Universe sees the asteroids as the remains of the most recent major event in solar system history. Grooves (called rilles when they are found on larger worlds) and craters were carved in groups by one or several electrical discharge events. The asteroids contain four belts and about nineteen families of bodies. Ida and Dactyl are members of the Koronis family, the largest asteroid family. The asteroids within this family follow similar orbits and have similar composition, indicating that they may have originated from catastrophic break-up of a single parent body. The fact that Ida has a moon is also evidence of a catastrophic event. For an asteroid to capture another asteroid gravitationally is almost impossible unless the two bodies escaped together from a larger gravitational influence. Another detail about the asteroids was pointed out by astronomer Tom Van Flandern. Analysis of their orbits (including the four belts and nineteen families mentioned above), taken in conjunction with the orbits of most long-term comets indicates that both the asteroids and comets had a common origin in a recent explosive event. ('Recent' is defined by the orbit analyses as about 3 million years ago.) The Electric Universe agrees with this analysis, if not with the event that Van Flandern postulates. The asteroids were formed in a universe that is 99% plasma, but the standard theories about how they formed and evolved were developed by researchers who believe plasma has little to do with astronomy. So as we look forward to more detailed asteroid data from space missions, we should continue to expect the unexpected. TPOD July 2: Craters in the Lab |
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