October 3, 1995
The universe is under no obligation to make sense to us, and yet here you are — a collection of atoms that somehow learned to think, to...
Deimos: A Small Martian Moon
Birthday · October 3, 1995
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APOD published October 3, 1995. Full image credits are on the original APOD entry below. A publication-date match, not a photo taken on your date. Independent of NASA.
Mars has two tiny moons, Phobos and Deimos. Pictured above is Deimos, the smallest moon of Mars. In fact, Deimos is the smallest known moon in the Solar System measuring only 9 miles across. The diminutive Martian moons were discovered in 1877 by Asaph Hall, an American astronomer working at the US Naval Observatory in Washington D.C. The existence of two Martian moons was predicted around 1610 by Johannes Kepler, the astronomer who derived the laws of planetary motion. In this case, Kepler's prediction was not based on scientific principles, but his writings and ideas were so influential that the two Martian moons are discussed in works of fiction such as Jonathan Swift's "Gulliver's Travels", written in 1726, over 150 years before their actual discovery.