No matter how fast the universe is expanding, shouldn't gravity eventually make it recollapse?
Even if the universe is expanding or even accelerating, wouldn't gravity eventually slow the expansion? No matter how big the force of velocity, wouldn't gravity, however small, eventually whittle down the expansion?
No, it actually wouldn't. This isn't the greatest analogy in the world, but it's sort of like cutting a string in half, and then cutting one of the halves of the string in half, and then cutting that in half, etc. You can keep cutting forever, and you'll never be completely out of string. You'll never be out of string, because you keep cutting off less and less each time.
Likewise, gravity can slow down the expansion of the universe, but it keeps doing so by less and less as time goes on (because it's not as strong over larger distances). So it's not hard to imagine a universe in which the expansion never gets below a certain rate, because the effects of gravity can never get it quite that low.
Get More 'Curious?' with Our New PODCAST:
- Podcast? Subscribe? Tell me about the Ask an Astronomer Podcast
- Subscribe to our Podcast | Listen to our current Episode
- Cool! But I can't now. Send me a quick reminder now for later.
- Could you tell me about the life cycle of galaxies?
- How do we know if the universe will keep expanding forever?
- How can observations of the distant universe prove that the expansion is accelerating *now*?
- How do supernovae show us that the Universe's expansion is accelerating?
How to ask a question:
If you have a follow-up question concerning the above subject, submit it here. If you have a question about another area of astronomy, find the topic you're interested in from the archive on our site menu, or go here for help.Table 'curious.Referrers' doesn't existTable 'curious.Referrers' doesn't exist
This page has been accessed 15597 times since May 14, 2003.
Last modified: May 24, 2003 5:38:36 PM
Ask an Astronomer is hosted by the Astronomy Department at Cornell University and is produced with PHP and MySQL.
Warning: Your browser is misbehaving! This page might look ugly. (Details)