From: LARRY KLAES (ljk4_at_msn.com)
Date: Mon Jul 05 2004 - 16:31:41 PDT
This is from Phil Plait's Bad Astronomy Newsletter:
An anniversary with a bang
Yesterday as I write this was the 228th anniversary of the signing
of the United States Declaration of Independence. That's a long
time by human standards, but yesterday marked an even longer one:
the 950th anniversary of the supernova explosion that signaled the
birth of the Crab Nebula! On July 4, 1054, a star exploded in Taurus.
Over the centuries, the expanding gas formed into one of the most
beautiful and intriguing objects in the sky. It's been studied
so much that some people say all of astronomy can be divided into
two areas: the Crab Nebula, and everything else.
See for yourself:
http://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search?crab You'll find lots of amazing things to see and read there about the Crab.
http://www.badastronomy.com/bitesize/sn87a_discovery.html It's the story of another exploding star, Supernova 1987A,
And before I get a zillion emails saying "But the Crab is 5600 light
Confused? Me too! So go here and read about all this:
http://math.ucr.edu/home/baez/physics/
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: Mon Jul 05 2004 - 16:44:39 PDT
If you're unsure about what a supernova is, don't fret! I took
care of that here:
but the tales are similar.
years away, so it really blew up 5600 + 950 = 6550 years ago!"
I'll note that this isn't really the case. You aren't thinking
Einsteiningly (which may very well be the first time that word
has ever been used!). There are odd relativistic ways of looking at
this. I need to do some more research about this, because it's been
a while since I studied it, but since information cannot travel faster
than light, it's legitimate to say that what we see is happening
"now". In other words, since we cannot go faster than light, it
is perfectly fine to say that this is the 950th anniversary. It just
depends on your definition of "now".