Astronomers say the Universe looks the same in all directions, what does that mean?

Question

Every interpretation i've read essentially just repeats the same statement, thus not explaining what it actually means.

If you painted a picture covering the outside of a fish-bowl, the fish would see something different for whichever way he looked...

Thanks for you input guys..

I thought Edthescienceguy answered my question most succinctly : "I beleive that it means the density of the external galaxies is the same in any direction."


scythian1950, campbelp2002, efw : all useful information, and all seemingly technically correct, and all worthy of note, although im not convinced that there is not "center" to the universe - as the universe is generally eliptical surely it has a central point?

texan pete: Im not sure thats accurate, could you provide a link to some info on that?

Answer 1

I beleive that it means the density of the external galaxies is the same in any direction.

Answer 2

The term is isotropy. There doesn't seem to be any preferential clumping or denisity maximum/minimum anywhere we look out into space. However, COBE measurements have revealed a very slight anisotropy in the microwave background, so that technically speaking, the universe does NOT look the same in "every direction". This result is of great significance to the Big Bang theory.

Answer 3

Essentially no matter where you are in the universe, it will appears as if you are in the center. The current theories describe the universe in a sphierical fashion, meaning that if you start off travelling in any direction you will eventually come back to the place you started. It is as if the entire iniverse is spread out over the surface of a ball.

Answer 4

Can you imagine being inside of a balloon? In all directions, space is expanding but you can't see what's on the outer edge...there is no edge in our universe (this is the best analogy i can think of). Most people think the Big Bang was an explosion in space, rather than it being an explosion OF space. The CMR is uniform in all directions and doesn't point to a central location...which is one evidence of what i'm saying.

If the Big Bang was an explosion in space, we'd be able to see beyond the edge of the expanding galaxies...into nothingness. But this is not the case.

Answer 5

It means there we see the same kinds of stars and galaxies in all directions. If you have seen one galaxy, you have seen them all is like saying if you have seen one tree you have seen them all. It is true in one sense and not in another sense. All trees have leaves and branches and are more or less tall plants. But a poplar looks much different from a pine. So a spiral galaxy looks much different from an elliptical galaxy. But we see all kinds of galaxies in all directions. And there are not more of one kind to be seen in a certain direction. We see about the same mix of different things in all directions.

Answer 6

Not if the pattern was the same. Think of polka dot paper.

Answer 7

is infinite