Naked Science Forum

Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: Gavin Campbell on 11/11/2009 09:30:03

Title: Where in the Universe is our galaxy?
Post by: Gavin Campbell on 11/11/2009 09:30:03

Gavin Campbell asked the Naked Scientists:
   
Hello Naked Scientists!

Firstly, keep up the good work on your great show (http://www.thenakedscientists.com/HTML/podcasts/)!

And now my question! Where in relation to the centre of the known universe does our galaxy reside?

Are we in relatively young, middle aged, or elderly galaxy?

If you know, It'd be great if you could answer this, as it's something I've always wondered about.

Thanks in advance,

Gavin from Canterbury.

What do you think?

Title: Where in the Universe is our galaxy?
Post by: Vern on 11/11/2009 11:45:15

All observations of the known universe show it to be as if it extends outward forever. It is only because we have this theory that the universe was created in a big bang that we imagine there is a size limit to the universe. But since no observations or experiments can detect an outward edge to the universe, we can not know our position in relation to our imagined size limit of the universe.

Title: Where in the Universe is our galaxy?
Post by: Mr. Scientist on 12/11/2009 02:14:09

There is a very eliquent way to put ourselves on the inter-galactic map.


According to theory, big bang occurred in every point in the spacetime metric. That would make us somewhere near the center of the universe, so long as you can comprehend that every other point which is around you is itself also the center of the cosmos.

In a much less exuberant description (in relation to our position in the milky way), we are somewhere near the edge of the galaxy.

Title: Where in the Universe is our galaxy?
Post by: itisus on 09/12/2009 05:28:59

I'm not an astronomer, but would guess that we are spatially near the center of the known universe.  It depends on how much is obscured by our galaxy and other nearby structures, but otherwise we should see stuff at approximately the same redshift in all directions.

Actually, imho, I am the exact center.

Hmmm, there is no center since we just see stuff further away at an earlier time.  So what is most central depends on how you weight space and time.  And if you consider the unknown universe, there is no center since there is no edge spatially (and maybe temporally).

For the best answer, see my second paragraph.

Title: Where in the Universe is our galaxy?
Post by: LeeE on 09/12/2009 20:13:51

In purely spatial terms we are at the center of the known universe, as the qualifier known in respect to the universe refers to our knowledge of it.

In terms of space-time, we appear to be on the extreme boundary of the universe, unless that is, you believe in fate and destiny, and that the future has has already happened.

Title: Where in the Universe is our galaxy?
Post by: Mr. Scientist on 10/12/2009 05:21:28

Quote from: LeeE on 09/12/2009 20:13:51

In purely spatial terms we are at the center of the known universe, as the qualifier known in respect to the universe refers to our knowledge of it.

In terms of space-time, we appear to be on the extreme boundary of the universe, unless that is, you believe in fate and destiny, and that the future has has already happened.

Well said.

Title: Where in the Universe is our galaxy?
Post by: yor_on on 12/12/2009 19:11:50

I would like to answer the caption first "Where in the Universe is our galaxy?"

Here?

As for a center :)

Title: Where in the Universe is our galaxy?
Post by: syhprum on 12/12/2009 22:16:34

The doctrine off the church has been confirmed by science, we really are at the centre of the universe