·If the Universe is only 14 billion years old, why isn't the most distant object we can see 7 billion light

Question

·years away?

Answer 1

Light from a remote location is not like a sound echo, you do not need to transmit and receive the signal. The remote objects (stars, pulsars, whatever) are already transmitters and here on earth we are just receiving that signal. Hence, we only talk about 1-way travel time for the signal, not 2-way travel time. On that basis, we shoudl be able to see light from 14 billion light years away, not 7 billion.

Answer 2

OK, I've looked at the other answers. Here's a different slant.

We CAN see back to within 500million years of the big bang but no further. Because of reasons beyond your question we can't see beyond this. The 'microwave background' [google Penzias and Wilson] is the echo of the 500million year old point.
The point is that this is MICROWAVE radiation and not visible radiation. It's microwave because the billions of degrees of temperature has cooled down as the universe has expanded. The heat has become spread out in the last 13.5billion years [14 billion - 500 million]
The reason we cannot SEE further than 7 billion light years is because the further something is the more it gets 'redshifted'. [look it up on google]
Beyond 7 billion LY objects get redshifted to the point where they no longer are visible to the human eye. They can still be detected by radio and microwave telescopes though.

Hope that helps

Answer 3

I've looked at the other answers, and all of them (so far) miss the point. Start from Earth today and travel up and out in any direction whatsoever. Now, assume that nothing will interfere with your continued travel in the same direction no matter how far you go.
Where will you eventually end up? At the "edge " of the Universe? Sorry, but no.
The only way that the Universe can be rationalized or visualized at all is in a field of at least 11 dimensions, all but four of which are "curled up" so tightly that they are undetectable. Like it or not, these dimensions are required by both relativity and the quantum theory. In other words, from the very tiniest bits of matter and energy to the inconceivably vastest, it takes 11 dimensions at a minimum to encompass the universe.
A consequence of this is that travel in any direction for an indefinite duration will bring you back to the starting point.
Now, to return to your question in the light of the above, if the Universe is 14 billion years old, (no only about it, that's a long, long time) the energy of it's creation is still out there, and can only proceed at the speed of light, so it can only be 14 billion light years from us to the nonexistent edge, actually 14 billion light years from us to us.

Answer 4

You seem to be assuming that the entire universe expanded in only one direction and that we somehow remained in the middle of the pack throughout. The primordial light sources of the universe would have radiated in all possible directions, marking a sphere up to 28 billion lightyears across. The light that could reach us is dependent on our position in the universe. Any light starting farther than 14B LY away would not have had enough time to get to us.

The light from the "far side" of the universe could only reach us if it originated within the temporal boundary imposed by the age of the universe. As the universe continues to age, we should be able to see objects that are farther away because their light will fall then within this limit.

Answer 5

Because the Universe is 14 billion years old, then light that has to travel more than 14 billion years has not had time to reach us yet.

However, any light coming our way from a region less than 14 billion light-years away can reach us (if nothing gets in the way). The main reason is not the size or distance (at least, not directly) it is one of time: In order to reach us, the light from an object 15 billion light years away would need 15 billion years to reach us and the universe is not old enough for that to have happened.

The Universe itself could be much bigger than 14 billion light-years across (could even be infinite). It is just that we cannot see anything from which the light has to travel more than 14 billion years.

Answer 6

Why would it be 7 Billion Light years away? as the light is only travelling FROM the object not to it and back, it should be 14 Billion light years away.

Answer 7

So, I see there are some theorists that answered the questions?! Matthank1, 28 billion is a rough estimate or a fact? I can safely say that you are wrong! I wonder how you figured the number.
Space, time and distance are not absolutes. This is where Matthank1 is completely wrong to say that "The fact is, things travel faster the further away they go, and this right here means that that their speed varies." Dude, objects have no direct relevance to the expansion, ok. It is the metric defining distance that is changing rather than objects moving in space!!! Look it up! Also speed DOES NOT "warps time itself" as Matthank1 says, so perhaps you, Matthank1, do not understand this well enough!!!

Answer 8

I think there is a bit more to it than that. First, if it was as you seem to be picturing it, it would be 28 billion light years across, because it would have expanded in all directions. The other assumption you make, the one that makes you wrong, is assuming that the expansion happens *at the speed of light*. It sure doesn't. The fact is, things travel faster the further away they go, and this right here means that that their speed varies. Plus speed warps time itself, so perhaps you do not understand this well enough.

Answer 9

Per relativity theory ,time is relative . It is a function of the location of the frame of reference. It appear different to differnt observers at different location of the Universe.

Answer 10

It takes time for light to travel.