This Day In Astro History

Janus as backlit from Saturn

March 2001 image of 1950DA by Arecibo.

February 23


2005 - Cassini snaps a backlit picture of Janus, a moon of Saturn.

1999 - Jupiter Venus conjunction. Conjunctions are not rare events. But planetary conjunctions are rarely this close and Venus and Jupiter are the two brightest objects in the sky, after the sun and moon, a very pretty sky view indeed.

1950 - Asteroid (29075) 1950 DA was discovered. It was observed for 17 days and then faded from view for half a century. Then, an object discovered on 31 December 2000 (New Year's Eve) was recognized as being the long-lost 1950 DA. Further observations of this rock by Goldstone and Arecibo telescopes describes the 1.1 km diameter rock as asymmetrical with a 2.1 hour spin, the spinniest rock yet found in our solar system. 

Analysis performed by Giorgini et al and reported in the April 5, 2002 edition of the journal Science ("Asteroid 1950 DA's Encounter With Earth in 2880: Physical Limits of Collision Probability Prediction") determined the impact probability as being at most 1 in 300 and probably even more remote, based on what is known about the asteroid so far. At its greatest, this could represent a risk 50% greater than that of the average background hazard due to all other asteroids from the present era through 2880, as defined by the Palermo Technical Scale (PTS value = +0.17). 1950 DA is the only known asteroid whose hazard could be above the background level. 

1987 - Supernova in the Large Magellanic Cloud visible to naked eye, as a result of explosion of blue supergiant Sanduleak 69 deg. 202. Known as SN1987A This was the first "nearby" supernova in the last 3 centuries. NASA scientists using the International Ultraviolet Explorer (IUE) was launched into Earth orbit in January1978 by a Delta rocket from Cape Canaveral, Fla., in cooperation with the European Space Agency (ESA) and the British Science and Engineering Research Council. Managed by Goddard Space Flight Center with the ESA in Villafranca, Spain.
venus jupiter
Venus and Jupiter lineup 
for a pretty sky view.

Supernova 1987A SN1987A 
Hubble Space Telescope 
Image taken in 1984

IUE spectrum of supernova1987a
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It is my conclusion that human evolution and the motions of matter in space are intrinsically linked. The observation and understanding of the complexity of biological history on Earth cannot be complete without the tandem observation and understanding of a dynamic greater cosmos. - SpaceGene