1. Member
Join Date
Aug 2005
Posts
14

## Staying Still?

So we know that we are all in motion in the universe. And I know that, since we are moving, and everything around us is moving, we have to take that fact into consideration when we do any kind of calculation and observation. I think general relativity comes in handy here.

But...

Could we not measure how fast we are moving? and maybe launch a spaceship in the opposite direction enough so that we will come to a stand still in the universe? If that could happen, would everything become easy to measure? The expansion of the universe for example or the rate at which it expands? maybe?

2. Originally Posted by justinv3
But...

Could we not measure how fast we are moving?
The ultimate question is, relative to what? Answer that, and the measurement is usually fairly easy.

3. Originally Posted by justinv3
Could we not measure how fast we are moving? and maybe launch a spaceship in the opposite direction enough so that we will come to a stand still in the universe? If that could happen, would everything become easy to measure? The expansion of the universe for example or the rate at which it expands? maybe?
First, we can't measure "how fast we are moving," since there is no absolute reference frame. People used to believe there was an "ether", but it was shown not to exist. So motion cannot be measured in the way you imagine.

So that invalidates the second question.

Then, for the third and fourth question, if one accepts the "cosmological principle", the expansion of the universe would be the same wherever you measure it from.

4. Originally Posted by Jens
First, we can't measure "how fast we are moving," since there is no absolute reference frame.
Actually, we can measure how fast we are moving, and what direction relative to the frame in which the Cosmic Microwave Background Radiation does not have a bipolar temperature distribution.

We do not (currently) have the capability of building a rocket that could get a probe going nearly that fast.

5. Originally Posted by antoniseb
Actually, we can measure how fast we are moving, and what direction relative to the frame in which the Cosmic Microwave Background Radiation does not have a bipolar temperature distribution.

We do not (currently) have the capability of building a rocket that could get a probe going nearly that fast.
Actually? That is still not assured to be an absolute reference frame.

6. Originally Posted by hhEb09'1
That is still not assured to be an absolute reference frame.
I didn't claim it to be absolute, and the OP didn't say they were looking for absolute. The OP was about looking for a reference frame that required less work subtracting the effects of ou peculiar movement. I specifically named a frame of reference in which the probe would not be considered to be moving.

7. Established Member
Join Date
Jun 2002
Posts
887
Here's A lovely Image of the Cosmic Microwave Background Dipole
Our local group of galaxies is moving at about 600 kilometers per second relative to the CMB.

8. Originally Posted by antoniseb
I didn't claim it to be absolute, and the OP didn't say they were looking for absolute.
Sorry, I thought you were responding to Jens's post.

9. Originally Posted by hhEb09'1
Sorry, I thought you were responding to Jens's post.
I was, but if you read my brief post entirely you'd have seen the phrase:
...relative to the frame in which...
I didn't read Jens as using the phrase absolute reference frame either. Those were your words needlessly injected into Jens request.

10. Originally Posted by antoniseb
I didn't read Jens as using the phrase absolute reference frame either. Those were your words needlessly injected into Jens request.
I was confused by this response at first, until I noticed that Jens did not make a request. Are you confusing Jens with the OP justinv3?

Jens did use the phrase, in their only post to this thread.

11. Originally Posted by hhEb09'1
Are you confusing Jens with the OP justinv3?
Yes, that is correct.

12. Order of Kilopi
Join Date
Feb 2005
Posts
7,182
This is a good idea for a sci-fi story.

Sir--we nulled out our planets rotation around the sun, stopped outside the galaxy--and now we've dropped out of the universe altogether.

Huh?

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