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(meteorobs) Black Holes and the Lives of Stars
Dear Joy,
Second time around. Again, I'm not a professional Astronomer or
Astrophysicist so if some of my info seems faulty to anyone out there feel
free to lambaste me. And, BTW, your questions in no way show ignorance. In
fact it's refreshing to see more interest in Astronomy versus Astrology, which
in my opinion is HORSE-SHIT and takes ADVANTAGE of ignorance.
The original mass of any star determines how it's life will end. We DO
understand this process now fairly well. We use our Sun's mass as the
baseline in determining the outcome of stellar lives, subsequently we give it
the value of ONE. The mechanism that stars use to "burn" or "shine" is none
other than nuclear fusion, the same way our own infamous H-bomb works by
turning hydrogen into helium.
As a star progresses through it's life, the helium ash builds up on the star's
surface and causes the star to grow and cool. The cooling changes a star's
color, and as they get bigger and bigger, stars like our Sun and larger,
become Red Giants- like Betelgeuse or Altair. These stars are SO big that if
you put them where the Sun is now, they would encase the Earth's orbit at
93,000,000 miles. It's the remaining fusion reactions now deep within the star
that support the expanding diameter. Eventually all the hydrogen burns out,
and the surface can no longer be supported so the star begins to collapse.
Stars with original solar masses of one or less collapse "gently" to dwarfs
(hence red dwarfs, brown dwarfs) and eventually burn out completely to black
cinders.
Stars with original solar masses of one to six collapse back to neutron stars
-- hence our discussion of the incredible densities in which they exist.
Eventually they too burn out to "black cinders," but ones with tremendous
gravitational properties (perhaps ONE answer to the Universe's "missing mass
mystery," but it's doubtful the Universe is old enough to have THAT many stars
that are "burned out"). Stars with solar masses greater than six, collapse
back to entities creating SO much gravity in such a small area that photons
(i.e., light) can no longer achieve escape velocity. Thus "Black Holes."
In Carl Sagan's book Cosmos in the chapter "The Lives of Stars" he used his
wonderful way of explaining things to describe it something like this....
"Someday, far, far in the future, there will be ONE last 'perfect day" on
Earth, after that the Sun will begin it's inevitable expansion, and perhaps
eventually even swallow it". But mankind will have been incinerated by the
Sun's expansion long before that, unless we find a way to leave the Earth and
inhabit other worlds in other systems. We are talking about an estimated 5
billion years from now, but I don't think it's too early to begin addressing
the problem NOW, at least perhaps through education. The masses need to be
reminded that the Sun WILL burn out and life on Earth WILL end. Unfortunately,
this fact is in direct disagreement with some religious beliefs AND for some
it is a topic that creates angst.
Dave Garrison
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