October 10, 2016 - Neptune’s Poached Moon
Neptune’s Poached Moon The largest moon of Neptune, and the seventh-largest moon in the solar system, Triton was first observed 170 years ago this week by William Lassell, an English amateur astronomer. At the time, Neptune itself had only been known about for seventeen days and was still called “Le Verrier’s planet,” after the French mathematician who correctly hypothesized its then-current position. An oddity among larger moons, Triton travels in a highly-tilted retrograde orbit around Neptune (in the opposite direction that the ice giant rotates). It also has a high density, and likely has a core of rock and solid metal beneath its water-and-nitrogen-ice crust. This leads scientists to believe that Triton originated in the Kuiper Belt, beyond Neptune, and was captured by Neptune’s gravity.
Image credit: NASA / JPL / USGS
Weekly Calendar
October 10-16, 2016
Holidays - Sky Events - Space History
Monday 10
Thanksgiving Day (Canada)
Columbus Day
1846: William Lassell discovers Triton, moon of Neptune
1980: Very Large Array dedicated
1983: Venera 15 orbits Venus
2007: ISS Expedition 16 crew launched
Tuesday 11
Yom Kippur begings at sunset
Mercury 0.9° north of Jupiter
1968: Apollo 7 launched
1969: Soyuz 6, 7 & 8 in space at once
1994: Magellan mission ends
2000: STS-92 Discovery launched
2005: Shenzhou 6 launched
Wednesday 12
1964: Voskhod 1 launched, first three-person space flight
1977: Shuttle Enterprise’s first glide test without aerodynamic tailcone
2008: ISS Expedition 18 crew launched
Thursday 13
Neptune 1.2° south of Moon
1773: Charles Messier observes M-51
1933: British Interplanetary Society founded
1968: Apollo 7 first live TV broadcast from space
2004: ISS Expedition 10 crew launched
Friday 14
1947: World’s first supersonic flight
1957: USAF announces X-20 Dyna-Soar project
1983: Venera 16 arrives in orbit around Venus
Saturday 15
Uranus at opposition
Uranus 3°north of Moon
1829: Asaph Hall born
1997: Cassini-Huygens launched
2003: Shenzhou 5 launched, Yang Liwei becomes first Chinese astronaut
Sunday 16
Full Moon 12:23 AM ET
Moon at perigee