Can you honestly say the universe has no center?

How does science work? And what's all this about quantum mechanics?

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QuantumT
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Re: Can you honestly say the universe has no center?

Post by QuantumT » Sat Jun 02, 2018 9:58 pm

We see time as: a physical difference between then and now. It could be a split second, but it's still time.
But before TBB, when nothing happened, there was still a period, or a gap where nothing happened. An actual time of no action.

So my claim is that time is older than TBB. Could be seconds. Minutes. Hours. Even years or millennia. Or more.

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Noax
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Re: Can you honestly say the universe has no center?

Post by Noax » Sat Jun 02, 2018 10:34 pm

gaffo wrote:
Sat Jun 02, 2018 6:53 am
diameter of universe is thought to be 160 billion light years.
Have a reference to this one? I've not heard this one, although it is close to the ~92 BLY diameter of the subset of all material which could have ever had a causal effect on what is now Earth. Such a definition is not an unreasonable definition of 'the universe'. If it is part of our causal past, in theory we should be able to see 'all of it', not just 3%. So maybe they got the 160 figure another way.
The event horizon is the defined edge of another definition of 'the universe', and it is a ball of around 30BLY currently, not much larger
however ive also heard that we can only see 3-percent of.

those two to not fit. if the latter is so then the diameter is much greater.
I got a smaller diameter actually, but using the Hubble-Sphere definition of what we can see (sphere where comoving mass is sub-light-speed relative to Earth) at a radius of 13.7 BLY (age of universe). That would be a diameter of 27.5 BLY, which is 3% the volume of a ball of diameter ~88 BLY, smaller than 160, and not too entirely far from my 92 BLY mentioned above.
i offer no answers ;-/.
I ask only from whence these values came. Just curious.
Maybe they also clue us in as to what they define as the part we can see, unless it comes from a different source.

gaffo
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Re: Can you honestly say the universe has no center?

Post by gaffo » Thu Jun 07, 2018 1:42 am

Noax wrote:
Sat Jun 02, 2018 10:34 pm
Have a reference to this one? I've not heard this one,
I heard it on an Astronomy Now audio podcast about 10 yr ago. not sure the particular show though. I'm sure you can find it if you want too however.


Noax wrote:
Sat Jun 02, 2018 10:34 pm
The event horizon is the defined edge of another definition of 'the universe', and it is a ball of around 30BLY currently, not much larger
not quite, 13.8 bl yrs is the radius (30 bill for diameter) of the overservable universe............but all that matter WRT us that is seen via 13.8 bly way as also during that time via space expansion......................is actually much farther than what we see it as.

4 times farther.

Noax wrote:
Sat Jun 02, 2018 10:34 pm
however ive also heard that we can only see 3-percent of.

those two to not fit. if the latter is so then the diameter is much greater.
I got a smaller diameter actually, but using the Hubble-Sphere definition of what we can see (sphere where comoving mass is sub-light-speed relative to Earth) at a radius of 13.7 BLY (age of universe). That would be a diameter of 27.5 BLY, which is 3% the volume of a ball of diameter ~88 BLY, smaller than 160, and not too entirely far from my 92 BLY mentioned above.
i offer no answers ;-/.
I ask only from whence these values came. Just curious.
Maybe they also clue us in as to what they define as the part we can see, unless it comes from a different source.
my understanding is that the percentage we see now is becoming less and less of what the actual size of the universe - galaxies we see are dropping off of our abiliy to see them via the accelleration of space expansion (Dark Energy) - and so we prob saw more the 3-percent of all there is out there 10 billion yrs ago, but today it is only 3-pecent and tommorrow it will be .3 pecent.

Hyper-expansion shortly after (fractions of a second) the Big Bang, and later, simple Dark Energy acellaration of space as we have these last 13.8 billion years.

that is the theory anyway.

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Noax
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Re: Can you honestly say the universe has no center?

Post by Noax » Thu Jun 07, 2018 5:14 am

gaffo wrote:
Thu Jun 07, 2018 1:42 am
Noax wrote:
Sat Jun 02, 2018 10:34 pm
Have a reference to this one? I've not heard this one,
I heard it on an Astronomy Now audio podcast about 10 yr ago. not sure the particular show though. I'm sure you can find it if you want too however.
A link to an article if you can find it. Podcasts are not much my thing.
Noax wrote:
Sat Jun 02, 2018 10:34 pm
The event horizon is the defined edge of another definition of 'the universe', and it is a ball of around 30BLY currently, not much larger
not quite, 13.8 bl yrs is the radius
That would be the Hubble sphere. Event horizon is currently about 15BLY radius.

Noax wrote:
Sat Jun 02, 2018 10:34 pm
however ive also heard that we can only see 3-percent of.

those two to not fit. if the latter is so then the diameter is much greater.
I got a smaller diameter actually, but using the Hubble-Sphere definition of what we can see (sphere where comoving mass is sub-light-speed relative to Earth) at a radius of 13.7 BLY (age of universe). That would be a diameter of 27.5 BLY, which is 3% the volume of a ball of diameter ~88 BLY, smaller than 160, and not too entirely far from my 92 BLY mentioned above.
i offer no answers ;-/.
I ask only from whence these values came. Just curious.
13.7 (or 13.8 BY) is age of the universe. You quote it above even. Things at that distance 'now' are moving at lightspeed relative to us, assuming constant velocity, which isn't really true, so it isn't exactly the age of the universe. Anyway, I got 88 BLY by applying your 3% to 27.5 BLY diameter. 27.5 cubed is 3% of 88 cubed. I had no idea where else that 3% figure came from.
my understanding is that the percentage we see now is becoming less and less of what the actual size of the universe - galaxies we see are dropping off of our abiliy to see them via the accelleration of space expansion (Dark Energy) - and so we prob saw more the 3-percent of all there is out there 10 billion yrs ago, but today it is only 3-pecent and tommorrow it will be .3 pecent.
I know about that. I am just wondering where they got the figure of the 97% that we can't see. Most models of which I am aware don't put a finite limit on it like that. There is more stuff beyond anything that we could ever have seen.
Does this theory say there is no stuff outside this 160 BLY ball? Saying that is the whole universe without defining what they mean by that is pretty useless. Are we at the exact center of it? That would mean there is stuff beyond, but it just cannot possibly matter to us, so it doesn't really exist to us. If there really is no stuff beyond, we likely not be at the center, in which case they'd offer a figure for which way the center was.

Also, the current size within the Hubble Sphere is only about 0.5% of a ball of diameter 160 BLY, not 3%. Hence my wondering where they got that 3% figure.

Being a relativist, I'm all for being at the center of the universe. There is no 'is real' about anything. There is only 'is real to X', where X can be anything, not just observers.

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Necromancer
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Re: Can you honestly say the universe has no center?

Post by Necromancer » Thu Jun 07, 2018 9:08 am

We are certainly not in position to say where it is, either way. :D

gaffo
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Re: Can you honestly say the universe has no center?

Post by gaffo » Sun Jun 10, 2018 9:00 pm

Noax wrote:
Thu Jun 07, 2018 5:14 am
gaffo wrote:
Thu Jun 07, 2018 1:42 am
Noax wrote:
Sat Jun 02, 2018 10:34 pm
Have a reference to this one? I've not heard this one,
I heard it on an Astronomy Now audio podcast about 10 yr ago. not sure the particular show though. I'm sure you can find it if you want too however.
A link to an article if you can find it. Podcasts are not much my thing.
Noax wrote:
Sat Jun 02, 2018 10:34 pm
The event horizon is the defined edge of another definition of 'the universe', and it is a ball of around 30BLY currently, not much larger
not quite, 13.8 bl yrs is the radius
That would be the Hubble sphere. Event horizon is currently about 15BLY radius.

Noax wrote:
Sat Jun 02, 2018 10:34 pm
however ive also heard that we can only see 3-percent of.

those two to not fit. if the latter is so then the diameter is much greater.
I got a smaller diameter actually, but using the Hubble-Sphere definition of what we can see (sphere where comoving mass is sub-light-speed relative to Earth) at a radius of 13.7 BLY (age of universe). That would be a diameter of 27.5 BLY, which is 3% the volume of a ball of diameter ~88 BLY, smaller than 160, and not too entirely far from my 92 BLY mentioned above.
i offer no answers ;-/.
I ask only from whence these values came. Just curious.
13.7 (or 13.8 BY) is age of the universe. You quote it above even. Things at that distance 'now' are moving at lightspeed relative to us, assuming constant velocity, which isn't really true, so it isn't exactly the age of the universe. Anyway, I got 88 BLY by applying your 3% to 27.5 BLY diameter. 27.5 cubed is 3% of 88 cubed. I had no idea where else that 3% figure came from.
my understanding is that the percentage we see now is becoming less and less of what the actual size of the universe - galaxies we see are dropping off of our abiliy to see them via the accelleration of space expansion (Dark Energy) - and so we prob saw more the 3-percent of all there is out there 10 billion yrs ago, but today it is only 3-pecent and tommorrow it will be .3 pecent.
I know about that. I am just wondering where they got the figure of the 97% that we can't see. Most models of which I am aware don't put a finite limit on it like that. There is more stuff beyond anything that we could ever have seen.
Does this theory say there is no stuff outside this 160 BLY ball? Saying that is the whole universe without defining what they mean by that is pretty useless. Are we at the exact center of it? That would mean there is stuff beyond, but it just cannot possibly matter to us, so it doesn't really exist to us. If there really is no stuff beyond, we likely not be at the center, in which case they'd offer a figure for which way the center was.

Also, the current size within the Hubble Sphere is only about 0.5% of a ball of diameter 160 BLY, not 3%. Hence my wondering where they got that 3% figure.

Being a relativist, I'm all for being at the center of the universe. There is no 'is real' about anything. There is only 'is real to X', where X can be anything, not just observers.
i thank you for reply, but there is no way I'm going to try to find a link to a podcast 10-8 yrs ago. not sure why they made the 3-pecent claim (outside of "space inflation" - they offered no particulars - per my poor memory a decade later at least).

I concur with your reply to me and again i offer no answers, just rememberances.

i wish you well.

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