Is the Universe bigger than we think?

In summary, the conversation discusses the possibility that the age of the universe may be greater than what we currently believe due to the limitations of our detection abilities in terms of space and time. It also touches upon the concept of inflation and its impact on our understanding of the size and expansion of the universe. The consensus among experts is that the universe is infinite in extent and our ability to see only a certain distance has no bearing on our understanding of its age. Further reading is recommended to better grasp these concepts.
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Trailblzn
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Im a novice and I love reading all the great info here but I have a question. We think we know the age of the universe because thats as far as we can "see." Is it possible with inflation that the universe is actually bigger than we can detect and we are limiting the size based on our limited observational abilities?
As inflation happens, effectively, faster than the speed of light (between any given two points) and we can only see 14 billion years back, is it possible the data we need, to judge the age of the universe, is actually beyond our detection abilities. Could the age of the universe be greater because what we are seeing is just the limitations placed on our detecting abilities by space time? Could the "rest" of the universe have expanded beyond our ability to detect it, and the data never get to us because space time, between us and it, is expanding so rapidly that the radio waves, gama rays, light etc is actually getting farther away even though it is coming at us?
 
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  • #2
Trailblzn said:
Is the Universe bigger than we think?
It would be REALLY REALLY hard for that to be the case since the current consensus (not an established fact) is that the universe is infinite in extent. You can't GET bigger than that.

You fundamentally misunderstand modern cosmology. I encourage you to do some basic reading and you will quickly correct your misunderstanding.

The part of the universe that we can't see with light is the 400,000 years or so prior to the Surface of Last Scattering and the belief is that we are likely to be able, someday, to see further back than that with other technologies than are presently available.
 
  • #3
Thank you for your reply, I genuinely appreciate it. Can you elaborate on which part of my question fundamentally misunderstands modern cosmology? The link http://preposterousuniverse.com/writings/cosmologyprimer/index.html is broken, just an FYI. I understand (or think I understand) the balloon analogy. What I think is correct, the universe is expanding in all directions, it is expanding faster the farther it is away from us. It is or can be expanding faster than the speed of light so the stuff at the edges of the universe may be expanding faster than any thing can travel to us. Is this the part that I misunderstand? Do you have any other suggested materials for me to read? I really appreciate your assistance.
 
  • #4
Trailblzn said:
We think we know the age of the universe because that's as far as we can "see."
How far we can 'see' has nothing to do with it. We know the age because everything is moving away from us at a rate proportional to its distance from us, so simple extrapolation backwards gives us a time when it was all together. That works no matter how large or limited our sight distance is. Sight distance seems to be limited by speed of light. If it was twice as fast, we could see twice as far.

The infinite size consensus comes from the fact that it seems to look identical everywhere and not different this way than in some other direction. Hence it is reasonable to conclude that it looks similarly isotropic and homogeneous to the observers in those other places as well, in which case there is no edge (a place where there is more stuff on one side than the other).

As inflation happens, effectively, faster than the speed of light (between any given two points) and we can only see 14 billion years back
Inflation doesn't directly limit our sight distance. Time does, since (as phinds points out) the universe wasn't transparent at first, so we can only see back as far in time as when it was.
Inertial inflation doesn't limit sight distance, but accelerated inflation does since it forms an event horizon beyond which light can never reach here. We can see objects currently beyond that event horizon, but only because we're looking at a past version of it when it hadn't yet crossed the horizon. We can see the sun, but only as it was 9 minutes ago, not as it is currently. All the more so for really distant objects.
 
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  • #5
Trailblzn said:
Thank you for your reply, I genuinely appreciate it. Can you elaborate on which part of my question fundamentally misunderstands modern cosmology? The link http://preposterousuniverse.com/writings/cosmologyprimer/index.html is broken, just an FYI. I understand (or think I understand) the balloon analogy. What I think is correct, the universe is expanding in all directions, it is expanding faster the farther it is away from us. It is or can be expanding faster than the speed of light so the stuff at the edges of the universe may be expanding faster than any thing can travel to us. Is this the part that I misunderstand? Do you have any other suggested materials for me to read? I really appreciate your assistance.
This is all correct, except for the "may be expanding faster than the speed of light". It IS receding faster than c but no speeding tickets are issued because nothing has any proper motion faster than light. That is, it is not TRAVELING in the way you think it is. Spacetime is expanding which is not the same thing.

If you have read the link in my signature, you clearly didn't get it all, so I'd suggest another reading.

@Halc has just provided a good explanation of some of the rest of what you don't yet understand.
 
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1. Is the Universe infinite?

No, the Universe is not infinite. It is constantly expanding, but it does have a finite size. Scientists estimate that the observable Universe is about 93 billion light years in diameter.

2. How do we measure the size of the Universe?

Scientists use a variety of methods to measure the size of the Universe, including the cosmic microwave background radiation, the redshift of galaxies, and the distances between celestial objects.

3. Can we ever know the exact size of the Universe?

No, it is impossible for us to know the exact size of the Universe. As it continues to expand, the observable Universe will always be larger than what we can currently measure.

4. Are there other universes besides our own?

There are many theories about the existence of other universes, but there is currently no concrete evidence to support their existence. The concept of multiple universes is still a topic of ongoing research and debate among scientists.

5. Will the Universe ever stop expanding?

It is currently believed that the Universe will continue to expand forever. However, the rate of expansion may change over time due to various factors, such as the amount of dark matter and dark energy present in the Universe.

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