Re: Why are the differences between both Big Bang and Big Crunch theories?
Date: Thu Oct 1 04:05:48 1998
Posted by Ricky J. Sethi
The Big Bang and the Big Crunch are concerned with the beginning and
the end of the universe, so to speak. As you're probably aware, the
Big Bang is the currently accepted theory for the origin and evolution
of the Universe. Briefly, it states that the Universe started as a
point that was smaller than an atomic nucleus about 15 billion years
ago. That point of energy "exploded", and this instantaneously
expanding point created space, time, and matter... basically the
Universe as we know it.
The Big Bang is tremendously more complicated than I've led you to
believe. Luckily for me, however, your question concerns the Big
Crunch. The Big Crunch is actually significantly easier to understand
than the Big Bang. The Big Bang describes how the Universe started.
The Big Crunch, however, deals with how the Universe might end. And
this rests simply on one thing: how much matter there is in the
Around 1920, a Russian mathematician by the name of Aleksander
Friedmann proposed a theory about the end of the Universe. There were
three possibilities for us in that theory, each relying on a
critical density of matter in the Universe.
The proof for the Big Bang is quite abundant. And recently, there has
been mounting evidence that there might not be enough matter in the
Universe to result in the Big Crunch and that the Big Chill is the
most likely fate for our Universe. However, this is an incredibly hot
(pardon the pun) field and the subject is also, as I mentioned before,
much more complicated than how I've presented it. A good introductory
book on all this is Scientific American's From Quarks to the
Cosmos (availble at any good library). Of course, there's plenty
of stuff available on the Web, too. Just point your favourite browser
to any search engine and search for either "big bang" or "big crunch".
One great site that I found was Scott Siegel's Creation of a
Cosmology. Give them a look and if you have any further
questions, please don't hesitate to drop me a line.
- If the matter in the Universe were higher than the critical
density, then the matter would exert enough gravitational forces to
eventually cause the Universe to stop expanding and start falling
back in upon itself. When this happens, the Universe will end in an
event as cataclysmic as its creation, namely, the so-called Big
- If there isn't enough matter to exert enough gravitational force
to pull it back in on itself (i.e., amount of matter in the
Universe is less than the critical density), then the Universe
will continue to expand and end in the Big Chill.
- Finally, if the amount of matter were exactly the same as the
critical density, the universe would still expand indefinitely,
resulting, once again, in the Big Chill.
For more information on Astronomy, try the
in the MadSci Library
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