# Move one, How long does it take for another one to move?

Hi,all, problem:

2 stars, distance is 1 lightyear.

If I move one star, will the other star move 1 year later?

Basically, I want expose the problem that, how fast does a field travel.

PhanthomJay
Homework Helper
Gold Member
Hi,all, problem:

2 stars, distance is 1 lightyear.

If I move one star, will the other star move 1 year later?

Basically, I want expose the problem that, how fast does a field travel.

Are you inquiring about the speed of the propagation of gravity? As far as I know, this is still undertermined. You might find all sorts of answers, from infinite, to 10 times the speed of light, etc.; but I believe the most widely accepted theory at this point in time says that it travels at the speed of light. I will ask the moderators to move this post to the special/general relativity section, if it belongs there.

Are you inquiring about the speed of the propagation of gravity? As far as I know, this is still undertermined. You might find all sorts of answers, from infinite, to 10 times the speed of light, etc.; but I believe the most widely accepted theory at this point in time says that it travels at the speed of light. I will ask the moderators to move this post to the special/general relativity section, if it belongs there.

Thanks for replay. I am wondering, is the speed of information(field) travel at the speed of light, then about wavefunction sperad all over the space? refer to my another question, see: