Just because the universe is 13.7 billion years old does not mean the radius of the observable universe 13.7 billion light years. Due to the expansion of the universe an objects light observed from 13.7 billion years would put the object roughly 46 billion light years away at present day. Thus the radius is around 46 billion light years.
Not quite true. We can see light that was emitted 13.7 billion years ago but that light has traveled about 45 billion light years once you account for redshift.
The light that we see today is no older than 13.7 billion years. We can’t see beyond this. What we do know is that the objects that emitted that light are now roughly 45 billion light years away due to expansion. I think the terminology is bad, everything we see is at most 13.7 billion years old, I would call that the observable universe. We know space has expanded to at least 45 billion light years, I would call that our cosmic horizon.
Accounting for the expansion of space, the radius of the observable Universe needs to be corrected to about 14.26 gigaparsecs (approx. 46.5 billion l.y.). One could argue that the observable Universe is "the Universe" given that what lies beyond the boundary of the observable Universe is inherently unknowable.
Then how can we have a map of the entire universe? I feel like I'm missing something here. Because having the map of the universe is like having a map of Earth before anyone travelled around Earth and made a map of it.
Let me ask something at this point that I've been trying to obtain an answer for over the past few months: assuming you believe in the big bang theory and that we all originated from a single point and are going a speed that has never even been close to half the speed of light, why is the 'observable universe' even plausible? We'd certainly see redshift, sure, but we wouldn't be limited to what was available to see.
Hi DBR, I don't completely understand your question, but it seems like you have some confusion on the topic. Big Bang cosmology simply posits a moment in history when the Universe began expanding (not necessarily where "we" originated from). There is unambiguous evidence to support this (see my other videos). Because light travels at a finite speed, there are parts of the Universe so far away that light from those locations hasn't had time to reach us yet. That's why the idea is plausible.
Is it possible to find something more than 13.7B ly away by accident, leading to a recalculation to a new age of the universe? So if something is found and proven to be 14B ly away, would we restate the age of the universe to be 14B years old? Or are we set on 13.7B ly?
A lot of mistakes and misconceptions on this video. It ignores metric expansion of space. I strongly recommend that you read Tamara M. Davis and Charles H. Lineweaver paper "Expanding Confusion: common misconceptions of cosmological horizons and the superluminal expansion of the Universe".
More fun facts! the Universe is now thought to be "flat" rather than folded or shaped. Ergo, what we "observe" can be no more than 5% of the total. Very big numbers....
since everything originated from the big bang which occurred 13.7 billion years ago, why didn't we see everything there is to see but in a distant past. what i mean is that we saw the entire universe as it was 13.7 billion years ago since then the universe expanded during that period of time and has changed for a period of 13.7 billion years right? to look far away is the same as to look in the past.
It is ridiculous to assume that we are at the centre of the universe and therefore it is meaningless to suggest there is a 13.7 billion light year radius around us!
Just because the universe is 13.7 billion years old does not mean the radius of the observable universe 13.7 billion light years. Due to the expansion of the universe an objects light observed from 13.7 billion years would put the object roughly 46 billion light years away at present day. Thus the radius is around 46 billion light years.
Not quite true. We can see light that was emitted 13.7 billion years ago but that light has traveled about 45 billion light years once you account for redshift.
The light that we see today is no older than 13.7 billion years. We can’t see beyond this. What we do know is that the objects that emitted that light are now roughly 45 billion light years away due to expansion. I think the terminology is bad, everything we see is at most 13.7 billion years old, I would call that the observable universe. We know space has expanded to at least 45 billion light years, I would call that our cosmic horizon.
Accounting for the expansion of space, the radius of the observable Universe needs to be corrected to about 14.26 gigaparsecs (approx. 46.5 billion l.y.). One could argue that the observable Universe is "the Universe" given that what lies beyond the boundary of the observable Universe is inherently unknowable.
Then how can we have a map of the entire universe? I feel like I'm missing something here. Because having the map of the universe is like having a map of Earth before anyone travelled around Earth and made a map of it.
Let me ask something at this point that I've been trying to obtain an answer for over the past few months: assuming you believe in the big bang theory and that we all originated from a single point and are going a speed that has never even been close to half the speed of light, why is the 'observable universe' even plausible? We'd certainly see redshift, sure, but we wouldn't be limited to what was available to see.
Hi DBR, I don't completely understand your question, but it seems like you have some confusion on the topic. Big Bang cosmology simply posits a moment in history when the Universe began expanding (not necessarily where "we" originated from). There is unambiguous evidence to support this (see my other videos). Because light travels at a finite speed, there are parts of the Universe so far away that light from those locations hasn't had time to reach us yet. That's why the idea is plausible.
thanks a ton... :D very helpful
Is it possible to find something more than 13.7B ly away by accident, leading to a recalculation to a new age of the universe? So if something is found and proven to be 14B ly away, would we restate the age of the universe to be 14B years old? Or are we set on 13.7B ly?
The true age of the universe is not known, 13.7B is just the best estimate and a widely accepted one. regards
A lot of mistakes and misconceptions on this video. It ignores metric expansion of space. I strongly recommend that you read Tamara M. Davis and Charles H. Lineweaver paper "Expanding Confusion: common misconceptions of cosmological horizons and the superluminal expansion of the Universe".
More fun facts! the Universe is now thought to be "flat" rather than folded or shaped. Ergo, what we "observe" can be no more than 5% of the total. Very big numbers....
Observable universe must be wider than 13.8 billion light years right? Because universe is exapnding
since everything originated from the big bang which occurred 13.7 billion years ago, why didn't we see everything there is to see but in a distant past. what i mean is that we saw the entire universe as it was 13.7 billion years ago since then the universe expanded during that period of time and has changed for a period of 13.7 billion years right? to look far away is the same as to look in the past.
Super explanation for those with basic knowledge. In France we would say: observable universe explained in potatoes 😄
Why is this topic so confusing to humans?
It is ridiculous to assume that we are at the centre of the universe and therefore it is meaningless to suggest there is a 13.7 billion light year radius around us!
Hi P. E TEACHER
Misleading information