March 3, 1996
Galaxies were colliding long before you were born, and they will keep colliding long after us all.
Uranus' Moon Ariel: Valley World
Birthday · March 3, 1996
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APOD published March 3, 1996. Full image credits are on the original APOD entry below. A publication-date match, not a photo taken on your date. Independent of NASA.
What formed Ariel's valleys? This question presented itself when Voyager 2 passed this satellite of Uranus in January 1986. Speculation includes that heating caused by the ancient tides of Uranus caused moonquakes and massive shifting of the moon's surface. In any event, a huge network of sunken valleys was found to cover this frozen moon, and some unknown material now coats the bottoms of many of these channels. Ariel is the second closest to Uranus outside of Miranda, and is composed of roughly half water ice and half rock. Ariel was discovered by William Lassell in 1851. Information: The Scale of the Universe Debate in April 1996