Rotating Question Curious About Astronomy? Ask an Astronomer

Is cosmic expansion happening on microscopic scales?

I'm not sure if this is an astrophysics question or a quantum physics question, or something totally stupid, but here goes...

If the universe is expanding (Hubble), and therefore space in general is expanding, then does it make sense to conclude that the space immediately around us (people, dogs, cats, chairs, etc) is also expanding, but at an imperceptible rate? In other words, is my right eye moving away from my left eye at some infinitesimally small rate due to universal expansion?

If so, then it must also be happening at a microscopic level. Does this microscopic expansion have any effect on atomic and/or quantum calculations? Do mathematicians and physicists include an expansion constant in their formulas when developing quantum theory?

Cosmic expansion is happening on a microscopic level, as you surmise, but at such a small rate that you would never notice it. On such scales other forces are so strong that while theoretically space is expanding, the particles in it are held together and do not move. Indeed, your right eye would be expanding away from your left eye due to this effect, except that they are held in place by all the bones and ligaments in your skull.

Cosmic expansion is not included in quantum calculations. The effect is far, far, FAR too small.

There is really only one place a calculation like you suggest would come in handy: calculating the energy density in a vacuum. As the vacuum expands, you get more total vacuum energy.

Thanks for a cool question!

January 1999, Karen Masters (more by Karen Masters) (Like this Answer), Dave Kornreich (more by Dave Kornreich) (Like this Answer)

Still Curious?

Get More 'Curious?' with Our New PODCAST:

Related questions:

More questions about Cosmology and the Big Bang: Previous | Next

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 18206 times since April 30, 2002.
Last modified: October 15, 2004 11:14:54 AM

Legal questions? See our copyright, disclaimer and privacy policy.
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)