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Moon and Jupiter

August 5, 2016

Jupiter is a solar-system vacuum cleaner. The giant planet hoovers up comets and asteroids like dust bunnies. They don’t disappear quietly, though. Instead, they can create fireballs that are bright enough to see from Earth.

Two amateur astronomers caught the most recent of these impacts back in March. They saw a short, bright burst of light from the planet’s edge. It probably was triggered by an asteroid the size of a small office building slamming into Jupiter’s atmosphere. It was moving so fast that it created an explosion equal to many hydrogen bombs.

The leader of a world-wide network of amateurs recently reported that such impacts probably happen every couple of months, on average. That estimate was based on what the amateurs have seen, and what they haven’t seen.

The best-known impact came in July of 1994, when Jupiter was hit by the shattered remains of Comet Shoemaker-Levy 9. The string of impacts left dark scars in Jupiter’s atmosphere for months.

Jupiter gets hit so often in part because it’s big — 11 times Earth’s diameter. The key factor, though, is that its gravity is much stronger than Earth’s, so it pulls in comets and asteroids from a greater range. And when they hit, they’re moving much faster than objects that hit Earth, so they create a much bigger bang.

Look for Jupiter early this evening. It looks like a bright star just above the Moon. They set not long after nightfall, so there’s not much time to enjoy the view.

Script by Damond Benningfield

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