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This Week's Finds in Mathematical Physics (Week 204)



 
 
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  #1  
Old March 26th 04, 05:00 AM
John Baez
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Default This Week's Finds in Mathematical Physics (Week 204)

In article ,
Ken S. Tucker wrote:

Turning to the evidence, Dr. Baez provides a
photograph of a nebula, 2.65 giga-light years away,


I never said *this* nebula was 2.65 giga-light years away!
Where did you get that idea?

"1) NGC 2359, the nebula around the Wolf-Rayet star HD56925,
picture at http://cfa-www.harvard.edu/cfa/hotimage/n2359.html"


This photo has the resolution of a standard planetary nebula
within OUR OWN GALAXY, that's typical of an old nova,


NGC 2359 is only about 5000 parsecs away. It's not
a planetary nebula caused by an "old nova", it's a nebula
caused by a Wolf-Rayet star. For details, see:

http://www.astro.umontreal.ca/~stlouis/IR.html

I'll be very clear, the photo Dr. Baez has quoted, ie.
photographing a *planetary nebula* in a galaxy over
2 giga-light years away is impossible with the Hubble
apparture, (to the depicted resolution at 2 billion LY's).
That must be a photo of a closer object.


Right! And I never claimed it was 2 billion light years away!
I just claimed it was a nebula formed by a Wolf-Rayet star.


  #2  
Old March 26th 04, 10:54 AM
alistair
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Default This Week's Finds in Mathematical Physics (Week 204)

Is the proton really stable, or does it eventually decay?
Why is there more matter than antimatter?

These two questions could be related.If the particle that causes a
proton
to decay was made of antimatter perhaps it decayed in the early
universe along with the rest of the antimatter.
  #3  
Old March 26th 04, 04:39 PM
Ken S. Tucker
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Default This Week's Finds in Mathematical Physics (Week 204)

(John Baez) wrote in message ...
In article ,
Ken S. Tucker wrote:

Turning to the evidence, Dr. Baez provides a
photograph of a nebula, 2.65 giga-light years away,


I never said *this* nebula was 2.65 giga-light years away!
Where did you get that idea?


I'm sorry Dr, Baez, that's my fault, my imagination
jumped and I was forming a picture of GRB030329
prior to it's alleged gamma event, using NGC 2359,
as a typical pre-event photo.

"1) NGC 2359, the nebula around the Wolf-Rayet star HD56925,
picture at http://cfa-www.harvard.edu/cfa/hotimage/n2359.html"
This photo has the resolution of a standard planetary nebula
within OUR OWN GALAXY, that's typical of an old nova,


NGC 2359 is only about 5000 parsecs away. It's not
a planetary nebula caused by an "old nova", it's a nebula
caused by a Wolf-Rayet star. For details, see:
http://www.astro.umontreal.ca/~stlouis/IR.html

Let's get our timing straight.
Obviously HD56925 was formed from interstellar
gas. Then to produce the *nil hydrogen burning
spectrum* it currently has, it followed the theoretical
evolution of a typical Wolf-Rayet star, you so well
described. What I understand from your essay is,
that a number of "nova" (not super or hyper nova)
events occur in the process of the evolution of the
Wolf-Rayet star, HD56925 in creating NGC2359.
Aside from the stellar wind NGC2359 appears
like a "planetary nebula", although more deformed
(and less symmetrical).

Compare that to the beautiful symmetrical form of
"Ring Nebula" (usually denoted planetary) in Lyra,
(M57, NGC6720), and recall this nebula was
theoretically formed by a nova, leaving the central
star intact.
((Won't get into the semantics of what's a planetary
nebula, except to say I thought these were from nova
events)).
Then constrast the "Ring Nebula" to the "Crab",
which is caused by a "super nova" event.
The apparent *coalesce* in the Crab suggests
a density sufficient to form gravitational binding, or
a highly asymmetrical explosion or perhaps a series
of related events in quick succession.

Neat stuff
Ken S. Tucker
 




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