As the universe expands, why don't galaxies get stretched out?
There is enough matter in a galaxy, that locally the expansion of the universe is stopped. You can think of this as the gravity of the galaxy holding it together, but really it's more fundamental than that. The rate of the expansion of the universe depends on the amount of matter (and dark energy) in the universe. If you just consider a tiny fraction of the universe which just includes a galaxy and total the matter in that region, it's more than enough to have already stopped the expansion in that region.
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.
- Is cosmic expansion happening on microscopic scales?
- How do galaxies collide in an expanding universe?
- Can "tired light theory" explain the observed redshifts of galaxies?
- Is the Local Group expanding along with the entire Universe?
- Will the diameter of a cluster of galaxies change with redshift?
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 23395 times since September 18, 2002.
Last modified: October 15, 2004 11:18:26 AM
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)