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HELP! - simple question!



 
 
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  #1  
Old April 22nd 05, 04:53 PM
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Default HELP! - simple question!

what DEATHS of celestial objects have humans witnessed without a
telescope?

(not including meteors)? with the dates if possible.

thanx

  #2  
Old April 22nd 05, 05:10 PM
Gaz
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Hi

Look up 'crab nebula china' in google

gaz

  #3  
Old April 22nd 05, 05:15 PM
Brian Tung
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lucky, err, vomit wrote:
what DEATHS of celestial objects have humans witnessed without a
telescope?

(not including meteors)? with the dates if possible.


*Without* a telescope? That means not even Shoemaker-Levy 9 is in
play, so you're probably limited to supernovae in our galaxy. So,
Kepler's in 1604, Tycho's in 1572, another one in Cassiopeia in 1181,
the Crab in 1054, Lupus in 1006, and two more reported by the Chinese
in 393 and 183, in Scorpius and Centaurus, respectively.

If we include supernovae in the telescopic era that were observed
without a telescope, you can add on at least the 1987 supernova in
the Large Magellanic Cloud. I don't know of any other supernovae
that were definitely visible (as such) to the unaided eye since
Kepler's supernovae, although to be sure, S Andromedae in 1885 must
have been close to visible, if not actually visible.

Brian Tung
The Astronomy Corner at http://astro.isi.edu/
Unofficial C5+ Home Page at http://astro.isi.edu/c5plus/
The PleiadAtlas Home Page at http://astro.isi.edu/pleiadatlas/
My Own Personal FAQ (SAA) at http://astro.isi.edu/reference/faq.txt
  #5  
Old April 22nd 05, 07:01 PM
Brian Tung
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Zane wrote:
Brian, please tell me you had to look some of that up. The thought
that you had all that in fast memory is too depressing.


Heh. I remember 1604, 1572, 1054, and 1006, but yes--I had to look
the rest of them up. Fortunately, I've posted about these supernovae
before, so I only had to Google my previous post.

Of course, 1987 is, I assume, in reasonably fresh memory for most folks
here. (Please don't anyone post a reply just to tell us all that you
weren't born yet in 1987.)

Brian Tung
The Astronomy Corner at http://astro.isi.edu/
Unofficial C5+ Home Page at http://astro.isi.edu/c5plus/
The PleiadAtlas Home Page at http://astro.isi.edu/pleiadatlas/
My Own Personal FAQ (SAA) at http://astro.isi.edu/reference/faq.txt
  #6  
Old April 22nd 05, 07:44 PM
Brian Tung
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Chris L Peterson wrote:
Not to mention an additional supernova every few centuries going back
many thousands of years, until the observers might reasonably no longer
be considered "human". None of these are precisely dated, of course,
although I'm sure that estimates can be made in some cases where we can
observe planetary nebulas.


Sure. There's the Gum Nebula, for one. That must have been some
supernova!

All of this depends on whether a supernova actually constitutes a
"death" in the sense the OP had in mind. I prefer to think of them as
transforming events. Certainly, the progenitor star continues its
existence, albeit in a quite different form.


I think it can certainly be said that Type Ia supernovae are death
events. And if a star is considered to be a fusor, then the other
supernovae are also death events.

Death, after all, is not end of existence. I too will exist after I
die (unless I'm atomized). I just won't be alive.

Brian Tung
The Astronomy Corner at http://astro.isi.edu/
Unofficial C5+ Home Page at http://astro.isi.edu/c5plus/
The PleiadAtlas Home Page at http://astro.isi.edu/pleiadatlas/
My Own Personal FAQ (SAA) at http://astro.isi.edu/reference/faq.txt
  #8  
Old April 22nd 05, 10:24 PM
Brian Tung
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Chris L Peterson wrote:
Well, yes, but then a star was never alive in the first place, so this
does very much depend on how "death" is used. Even in the case of a type
1a supernova, you are left with an active object in the same location as
the original pair of objects, and containing lots of the original
material. Death? I don't know. Anyway, it really just word games we are
playing here.


A star is commonly considered to be a fusor, isn't it? After the
supernova, it ceases to be a fusor. As a star, it dies. It's just
a lump of warm whatever after that, slowly cooling--just like a dead
human being.

I thought a Type Ia supernova commonly resulted in the complete
detonation of the progenitor star--I thought it was the Type II
supernovae that leaves a black hole, or neutron star, or whatever.
The Type Ia's partner might leave around some stuff, but I wouldn't
consider that to be part of the original star.

Brian Tung
The Astronomy Corner at http://astro.isi.edu/
Unofficial C5+ Home Page at http://astro.isi.edu/c5plus/
The PleiadAtlas Home Page at http://astro.isi.edu/pleiadatlas/
My Own Personal FAQ (SAA) at http://astro.isi.edu/reference/faq.txt
 




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