September 10, 2018 - Oddball Moon
Oddball Moon Hyperion is one of the oddest moons in the solar system. The largest of Saturn’s irregular, non-spherical moons, Hyperion is 410 km (255 mi) long, and 220 km (137 mi) at its narrowest width. Its odd potato shape suggests Hyperion is a remnant of a larger moon that was destroyed by a major impact. It is about half as dense as water, which means that Hyperion could be comprised of chunks of water ice with significant voids, or that lighter materials (frozen methane or carbon dioxide) could make up part of the moon. Hyperion rotates in a tumbling chaotic way through space as it orbits Saturn every 21 days. Hyperion was discovered independently by the English astronomer William Lassell, and the American father and son team of William and George Bond, 170 years ago this week.
Image credit: NASA / JPL-Caltech
Weekly Calendar
September 10 - 16, 2018
Holidays - Sky Events - Space History
Monday 10
1857: James Keeler born
1967: Surveyor 5 lands on Moon
1978: Venera 11 launched
2011: GRAIL spacecraft launched
Tuesday 11
1877: James Jeans born
1985: International Cometary Explorer satellite probes Comet Giacobini-Zinner (first comet flyby)
1997: Mars Global Surveyor arrives at Mars
Wednesday 12
Venus 10° south of Moon
1959: Luna 2 launched
1966: Gemini XI launched
1970: Luna 16 launched
1991: STS-48 Discovery launched
1992: STS-47 Endeavour launched
1993: STS-51 Discovery launched
2017: Soyuz MS-06 launched carrying ISS Expedition 53/54 crew
Thursday 13
Jupiter 4° south of Moon
1977: Second glide test of Space Shuttle Enterprise
1978: Venera 12 launched
Friday 14
1966: Gemini XI, docked with Agena booster rocket, reaches 850-mile-high orbit
Saturday 15
1965: “Lost in Space” premieres
1968: Zond 5 launched, first circumlunar spaceflight with living creatures (tortoises)
2016: Tiangong-2 space station launched
2017: Cassini mission ends with planned entry into Saturn’s atmosphere
Sunday 16
First Qtr Moon 7:15 PM ET
1848: First observation of Hyperion, moon of Saturn
1996: STS-79 Atlantis launched