December 21, 2015 - Swing Your Partner
Swing Your Partner The Hubble Space Telescope captured two spiral galaxies that are locked in an elegant but violent cosmic dance. The larger galaxy (top) is NGC 2207. The smaller galaxy is IC 2163. IC 2163 is swinging past NGC 2207 in a counter-clockwise direction, but it is not moving fast enough to escape NGC 2207’s grasp: IC 2163 will eventually circle around and swing past NGC 2207 again. This galactic square dance, with both partners locking their spiral arms together, will eventually cause repeated collisions and distortions of the two bodies. Billions of years from now, the two will merge into a single, more massive galaxy. Astronomers believe that many large galaxies (including our own Milky Way) are the result of similar galactic collisions. These galaxies are about 80 million light-years away.
Image credit: NASA / ESA / Hubble Heritage Team (STScI)
Weekly Calendar
December 21-27, 2015
Holidays - Sky Events - Space History
Monday 21
Moon at perigee
Mars 4° north of Spica
Solstice 11:48 PM ET
1968: Apollo 8 launched
1984: Vega 2 launched
1988: Cosmonauts Titov and Manarov return after spending one year aboard Mir space station
2011: Soyuz TMA-03M launched carrying ISS Expedition 30/31 crew
Tuesday 22
Ursid meteor shower
1966: Luna 13 launched
1966: First glide test of the HL-10 lifting body
Wednesday 23
Aldebaran 0.7° south of Moon
Ursid meteor shower
1672: Giovanni Cassini discovers Saturn’s moon Rhea
Thursday 24
1968: Apollo 8 enters lunar orbit
1978: Venera 11 lands on Venus
1979: European Space Agency launches first Ariane rocket
Friday 25
Christmas Day
Full Moon 6:11 AM ET
1642: Isaac Newton born
2003: Mars Express and Beagle 2 arrive at Mars
2004: Huygens probe separates from Cassini spacecraft
Saturday 26
Boxing Day (Canada, U.K., Australia)
First Day of Kwanzaa
Uranus appears stationary
Sunday 27
1571: Johannes Kepler born
1984: Meteorite ALH 84001 discovered