October 10, 1995
The atoms in your body have known many forms: star core, drifting dust, ocean mineral, living cell.
Dione's Lagrange Moon Helene
Birthday · October 10, 1995
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APOD published October 10, 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.
Saturn's moon Helene is very unusual in that it circles Saturn near the orbit of a bigger moon: Dione. Helene is situated in what is called a "Lagrange point" of Dione - a place of stability created by Dione's gravity. Were Helene to stray slightly from its orbit 1/6 ahead of Dione, the larger moon's gravity would cause Helene to move back toward the Lagrange point. Many massive orbital bodies have stable Lagrange points, including the Earth and Moon. Helene was discovered from the ground by P. Laques & J. Lecacheux in 1980. The photograph above was taken by Voyager 2 as it passed Saturn in 1981. NASA's Cassini mission to Saturn is currently scheduled for launch in October 1997.