

Harvard-Smithsonian Confirms Black Hole Existence after 40 Years - chermor
http://bostinnovation.com/2011/06/28/harvard-smithsonian-confirms-black-hole-after-40-years-proves-hawking-wrong/

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ender7
Wait, it's only 5 _million_ years old? That seems ludicrously young given
astronomical timescales.

I'm also curious how such a thing came to be. How did we get a binary system
with a much smaller, and presumably much older star (since it is now a black
hole), accompanied by a much larger, younger star?

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lutorm
Actually, the stars were very likely created together. The star that made the
black hole was likely much more massive. More massive stars have _shorter_
lifetimes than less massive ones (because the luminosity and consequently the
rate of fuel burning goes as something like M^3.5), so it died before the
companion.

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thirsteh
Original article from PhysicsWorld:
<http://physicsworld.com/cws/article/news/46362>

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AndrewHampton
From the article:

    
    
      "Black holes, if you recall, are created when stars run out of fuel and die. In dying, they collapse into a much smaller mass with such enormous gravity that it sucks in just about anything that comes light years near it."
    

I may be wrong, but doesn't the mass of the black hole roughly equal the mass
of the star? I know some is lost during the explosion, but I thought the mass
stayed roughly the same and just the volume significantly decreased.

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lutorm
Well, not really. The mass of the black hole created equals the amount of mass
that falls into it, of course, and to first order the mass of the BH will be
equal the mass of the _iron core_ of the star. That mass is however quite a
bit smaller than the mass of the star, and very much smaller than the
_initial_ mass of the star. (A star has to start out with a mass > 8* the mass
of the Sun to go supernova, and that will only guarantee that it forms a
neutron star whose mass will be of order 1 Solar mass. The rest is lost first
during the life of the star, as massive stars are so luminous they drive their
own matter off from the surface, and then ejected in the explosion itself.

Edit: The article has a number off, as it states that the black hole has a
mass of 15 Solar masses and that the companion is 19 times larger. The
original article says the companion is 19 Solar masses, which makes more
sense.

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JonnieCache
Interesting that Kip Thorne wanted a year of porn and Hawking wanted four
years of political satire, although the whole thing was obviously a joke.

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bfe
Even for normal low standards of science journalism, this article is awful.
"...such enormous gravity that it sucks in just about anything that comes
light years [sic] near it." An object passing light-years away would follow
the same hyperbolic trajectory as if interacting with a 15 solar mass peanut
butter sandwich.

