September 23, 2013 - SpongeBob of Saturn

SpongeBob of Saturn Rotating chaotically while it orbits Saturn every twenty-one days, Hyperion is one of the most bizarre moons in the solar system. Its irregular surface, pockmarked by surprisingly deep craters, gives Hyperion a sponge-like appearance. Data from the Cassini spacecraft, which made a close approach to Hyperion in 2005 and 2006, shed some light on what might cause this strange terrain. When meteorites fall on dense bodies, like the Moon, plumes of debris are ejected and eventually settle around the impact site, in effect repaving the surrounding surface by filling in older nearby craters. Hyperion, however, is so brittle and porous (Cassini found that over forty percent of it is empty space) that impacts create little or no debris, and can result in comparatively deep, well-preserved craters.

Image credit: NASA / JPL / Space Science Institute

Weekly Calendar

September 23-29, 2013

Holidays - Sky Events - Space History

Monday 23

1783: Caroline Herschel discovers NGC 253
1846: J. G. Galle discovers Neptune
1962: “The Jetsons” premieres
1977: Third glide test of space shuttle Enterprise

Tuesday 24

Mercury 0.8° north of Spica

1930: John Young born
1962: MOOSE astronaut rescue system proposed
1970: Luna 16 returns lunar soil samples
1999: IKONOS-1 launched

Wednesday 25

1973: 59-day Skylab 3 mission ends
1992: Mars Observer launched
1997: STS-86 Atlantis launched
2008: Shenzhou 7 launched
2013: Soyuz TMA-10M launched carrying ISS Expedition 37/38 crew

Thursday 26

Last Quarter Moon 11:56 PM ET

Friday 27

Moon at apogee

1814: Daniel Kirkwood born
2007: Dawn spacecraft launched

Saturday 28

Jupiter 5° north of Moon

Sunday 29

1977: Salyut 6 space station launched
1988: STS-26 Discovery launched, first shuttle flight since Challenger disaster
2001: First satellite launch from Alaska
2009: MESSENGER makes its third and final flyby of Mercury