This animation of comet 45P/H-M-P was made by bouncing radio waves off the comet. Credit: USRA
When the first close range photos of Rosetta’s Comet started coming in, a few of us joked it looked just like one of those rubber ducks we played with as kids in the bathtub. Only this duck was made of porous ice and dust and 2.5 miles (4 km) wide, though I suspect it would float if you had a tub big enough.
The recent close flyby of another mouthful of a comet, 45P/Honda-Mrkos-Pajdusakova, provided a not-to-be-missed opportunity to bounce radio waves off its nucleus and study the returning echoes to create close up if shadowy images. While asteroids routinely pass near Earth — there are millions of them in the neighborhood — close approaches of comets are relatively rare.
This rubber duck has a certain air of malevolence about it, doesn’t it? It’s a photo of comet 67/Churyumov-Gerasimenko taken by the Rosetta probe that went into orbit about the comet. Sunlight vaporizing comet ices creates jets or streamers of dust and gas which form a temporary, tenuous atmosphere around the comet called a coma. Credit: ESA/Rosetta/NAVCAM – CC BY-SA IGO 3.0
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