Thread: "Observable universe" vs actual universe

1. Originally Posted by DoggerDan
I just did something fairly unpredictable. I slapped myself. You're saying that if the universe is indeed infinite that there's a duplicate me out there somewhere with precisely the same molecules including those in my hand which just slapped my face?

Isn't it equally likely, statistically speaking, that there is infinite variation such that no two people would ever be exactly alike?
Not really. There aren't an infinite number of things you could do. There would be infinite copies of you who slapped their face, and infinite almost-copies of you who did not. While the number of things you could do is really beyond our comprehension, it is still finite and therefore contained an infinite number of times in the infinite set.

2. Originally Posted by m1omg
So either universe is smaller than 10^43000000000000 light years, or each of us has a dopplerganger. It all sounds very silly until you learn to appreciate the magnitude of numbers like this. You live in a ridiculously huge universe, you get ridiculously improbable things happening.
When you are talking about the dinension of the observable universe,,,you only are considering the positive dimensions: 10^n (where n>0 and near infinite)...but why you dont consider also the universes that could be in the negative dimensions (where n<0 and also possibly near infinite)?

There are the same possibility of having things, bodies and entities....into a very small dimensions...possibly near 10^-(10^100) meters !!!

3. Originally Posted by dapifo
When you are talking about the dinension of the observable universe,,,you only are considering the positive dimensions: 10^n (where n>0 and near infinite)...but why you dont consider also the universes that could be in the negative dimensions (where n<0 and also possibly near infinite)?

There are the same possibility of having things, bodies and entities....into a very small dimensions...possibly near 10^-(10^100) meters !!!
Can you show us, in appropriate mathematical detail, why you think the probability of such a system is the same?

4. Originally Posted by dapifo
When you are talking about the dinension of the observable universe,,,you only are considering the positive dimensions: 10^n (where n>0 and near infinite)...but why you dont consider also the universes that could be in the negative dimensions (where n<0 and also possibly near infinite)?

There are the same possibility of having things, bodies and entities....into a very small dimensions...possibly near 10^-(10^100) meters !!!
Are you implying that if we had the right equipment we could see little people running around and galaxies forming at scales several times smaller than the Planck Length? That's so off the wall that I don't even know what to say to it. How do you back this up?

5. Originally Posted by Hornblower
Can you show us, in appropriate mathematical detail, why you think the probability of such a system is the same?
Can you show us, in appropriate mathematical detail, why you think that not is similar?

The only difference is due our brain structure...it is easyer to imagine large things...till infinite...than smaler things....that we think they to need have a limit (??)...but why?..it is only a problem of our brain strunture...

You are talking as something possible (but silly) that "the universe is smaller than 10^43000000000000 light years, or each of us has a dopplerganger"...but you cannot shape and accept an universe smaller than Planck dimension....(???)

6. Originally Posted by primummobile
Are you implying that if we had the right equipment we could see little people running around and galaxies forming at scales several times smaller than the Planck Length? That's so off the wall that I don't even know what to say to it. How do you back this up?
I donīt think that we could see little people running around and galaxies forming,, as well we know now...but yes I think that is possible that other type of beings and entities could be there....Why do you see it so different that they exist at larger dimensions of 10^43000000000000 light years....and that could exist dopplerganger?

7. Because there is a limit to how small subatomic particles can be. Once you get so small there's nothing smaller to break it up into. There's nothing limiting how large of a space we live in and it's pretty easy to prove mathematically that in infinite iterations you will have infinite duplication. Something infinitely small is completely different and you need to back up what you said without attacking the argument and saying "if you can make it big you can make it small." That's not a case for what you are implying.

8. Originally Posted by primummobile
Because there is a limit to how small subatomic particles can be. Once you get so small there's nothing smaller to break it up into.
How can you ensure so categorically this?

You could say that "according to current theories ...", but always that in science somebody have made ​​such categorical statements ... they have always ended up being false ... remember the meaning of atom ...Now Plack (and streams) seams to be the smallest dimension....(???)

Do you really think that there is a limit for smallest particles?

9. Originally Posted by m1omg
Why do so many people think observable universe is the whole universe? [...] the accepted cosmology finite universe models generally predict an universe larger than any human idea of infinity - http://en.wikipedia.org/wiki/Orders_...9#Astronomical - the lowest boundary for the size of the universe is 250 billion years and the figure predicted by inflational models is more than 10 to the power of a googolplex [...] If the latter number is correct, the size of the entire universe is much, much, much higher compared to the observable universe than the size of the observable universe compared to a planck volume. [...] So no, our universe is not just 93 billion light years big (or 14 billion as some people not understanding comoving distance or the expansion of the universe believe).
Please, could you tell me which there is the "most" possible dimension that current (mainstream) physics forsee for the Whole Universe?

I supose that the Observable Universe is a sphere of 13.700 millions light years of radius.(??)

Originally Posted by m1omg
Our universe is probably so big that it contains a near infinite number of your identical twin, doing the exact same thing as you are doing right now. Now that is humbling.
Although that probabilistically it could be possible .... this is nothing more than a meaningless fallacy...because you donīt take into account the Time :

- The Time that this dopplergangers will exist....do they coexist in the same time?
- And If the succession of events will be the same ... and for how long....(1 second?... 10.000 milliosn of years?)

You only onsider an instant picture !!!!

10. Originally Posted by dapifo
Can you show us, in appropriate mathematical detail, why you think that not is similar?The only difference is due our brain structure...it is easyer to imagine large things...till infinite...than smaler things....that we think they to need have a limit (??)...but why?..it is only a problem of our brain strunture...

You are talking as something possible (but silly) that "the universe is smaller than 10^43000000000000 light years, or each of us has a dopplerganger"...but you cannot shape and accept an universe smaller than Planck dimension....(???)
My bold. No I cannot, and since I did not assert anything one way or the other I see no need to attempt any such thing. All I did was ask a question.

If I did wish to make such an analysis, I would need to learn the math and physics behind the best theory we have to date and then compare it step by step with an alternative scenario.

11. Originally Posted by Hornblower
If I did wish to make such an analysis, I would need to learn the math and physics behind the best theory we have to date and then compare it step by step with an alternative scenario.
OK..but first you have to take into account (consider) this possibility.... If you donīt accept this possibility ...then you will never need (wish) to make such an analysis, and you would never need to learn the math and physics behind the best theory we have to date and then compare it step by step with an alternative scenario.

12. Originally Posted by dapifo
OK..but first you have to take into account (consider) this possibility.... If you donīt accept this possibility ...then you will never need (wish) to make such an analysis, and you would never need to learn the math and physics behind the best theory we have to date and then compare it step by step with an alternative scenario.
For me it is not a matter of accepting or rejecting. I simply do not care. Perhaps a future unification of general relativity and quantum mechanics could enable discoveries that would make me change my mind.

13. I don't know why this thread was started in OTB. I'm not sure what exactly is the theme of this thread, and it seems to be rapidly turning into ATM. Rather than trying to sort out who is claiming what and dropping the various pieces into ATM, it is just closed. Anyone wants to further discuss this, start your own threads in an appropriate forum.

And dapifo, your posts here seem a lot like your recently closed thread in S&T on dimensions. If you wish to discuss your ideas on this any further, you need to start a thread in ATM.

14. After some discussion among the moderation team, we have decided to move this thread to Astronomy (from OTB) and reopen it.

There are speculative aspects to this topic, and that is fine. But advocacy of non-mainstream ideas will not be tolerated. Questions and speculation are fine, advocacy is not.

dapifo, if you discuss your "scale" ideas, or any other non-mainstream views in this thread again, you will be severely infracted and suspended; you will get no further warnings.

15. Originally Posted by m1omg
Why do so many people think observable universe is the whole universe? I see people making claims like "A googol is SO LARGE that it is even larger than the number of elementary particles in the universe" and they always cite the "observable universe" figures to make it seem "universe is really small in fact". There is a very real possibility that the universe might be in fact be infinite (meaning an infinite number of elementary particles so not even Graham's number might actually approach the actual number of particles in the universe anymore than a googol or the number 1 does) and even the accepted cosmology finite universe models generally predict an universe larger than any human idea of infinity - http://en.wikipedia.org/wiki/Orders_...9#Astronomical - the lowest boundary for the size of the universe is 250 billion years and the figure predicted by inflational models is more than 10 to the power of a googolplex - in fact that means that the universe is large enough to have a near-infinite number of cosmological horizons that are exactly the same as ours!

If the latter number is correct, the size of the entire universe is much, much, much higher compared to the observable universe than the size of the observable universe compared to a planck volume.

So no, our universe is not just 93 billion light years big (or 14 billion as some people not understanding comoving distance or the expansion of the universe believe). Our universe is probably so big that it contains a near infinite number of your identical twin, doing the exact same thing as you are doing right now. Now that is humbling.
If the universe began in a Big Bang 13.7 billion years ago, and as you and some theories say is big enough to "contains a near infinite number of your identical twin" .... 10 ^ 10 ^ 115 ym .... Then my questios is:

Which is the speed of the expansion of the Universe inflation? ... This must be huge! ... nearly infinite!

16. Originally Posted by dapifo
Which is the speed of the expansion of the Universe inflation? ... This must be huge! ... nearly infinite!
Expansion isn't measured as a speed. It is a "rate", a rate of change of scale; e.g. how long it would take for the distance between two point to increase by 10%. And if you think about that, that is what makes apparent speed proportional to distance.

So, equivalently, it can be measured as how velocity increases with distance. It is measured as about 74 (km/s)/Mpc. In other words, for every million parsecs of distance from the observer, the rate of expansion increases by about 74 kilometers per second. So it is actually quite small. but noticeable because the universe is really, really big.

Note that there is also a hypothetical early period (inflation) when the rate of expansion was much, much greater.

17. Then...13.7 billions years x 74 km/s = 13.700.000.000 x 365 x 24 x 60 x 60 x 74 km= (13.7x365x24x36x74) 10^11 = 2*10^19 km = 2* 10 ^22 meters?

18. Originally Posted by dapifo
Then...13.7 billions years x 74 km/s = 13.700.000.000 x 365 x 24 x 60 x 60 x 74 km= (13.7x365x24x36x74) 10^11 = 2*10^19 km = 2* 10 ^22 meters?
If that's the answer, what's the question?

Actually, you left out the "per megaparsec" part. The expansion rate between any two objects is dependent on the distance between them. If that distance is 1 Mpc, the rate is 74 km/sec. If the distance is 2 Mpc, the rate of expansion between them is 2x74 km/sec or 148 km/sec. Etc.

19. Originally Posted by Cougar
If that's the answer, what's the question?

Actually, you left out the "per megaparsec" part. The expansion rate between any two objects is dependent on the distance between them. If that distance is 1 Mpc, the rate is 74 km/sec. If the distance is 2 Mpc, the rate of expansion between them is 2x74 km/sec or 148 km/sec. Etc.
OK..OK..The question was ...

If the universe began in a Big Bang 13.7 billion years ago, and as you and some theories say is big enough to "contains a near infinite number of your identical twin" .... 10 ^ 10 ^ 115 ym .... Then my questios is:

Which is the speed of the expansion of the Universe inflation? ... This must be huge! ... nearly infinite!

20. Originally Posted by dapifo
OK..OK..The question was ...

If the universe began in a Big Bang 13.7 billion years ago, and as you and some theories say is big enough to "contains a near infinite number of your identical twin" .... 10 ^ 10 ^ 115 ym .... Then my questios is:

Which is the speed of the expansion of the Universe inflation? ... This must be huge! ... nearly infinite!
And ... hasn't that been answered?

21. Originally Posted by Strange
And ... hasn't that been answered?
OK yes...but it is not clear because :

1 pc = 3*10^16 m.....1Mpc = 3*10^22 m....near the obserable universe....then the universe in increasing very few.

And also at begeaning of Big-bang....slower.

How do yo spect that now the Universe could be larger than 10 ^ 10 ^ 115 ym ?????

22. The observable universe is currently, I believe, about 46 billion light years in radius; i.e. the stuff that emitted light 13.7bn years ago is now 46bn ly away.

As pointed out at the start of the thread, the whole universe may be be much bigger than that (or even infinite).

Note that even at the current rate of expansion there are objects with an apparent velocity away from us much greater than the speed of light. If the universe is large enough, that has always been true (because relative velocity is proportional to distance).

23. When you say Observable Universe...do you reffer to the part of the Whole Universe that we can see and detect?...Wny do you say that "the stuff that emitted light 13.7bn years ago is now 46bn ly away."?

When you say that Whole Universe may be be much bigger than that (or even infinite)...do you reffer to the Universe started in the Big-bang....or you include other space and Universes?

24. Originally Posted by dapifo
When you say Observable Universe...do you reffer to the part of the Whole Universe that we can see and detect?...Wny do you say that "the stuff that emitted light 13.7bn years ago is now 46bn ly away."?
Because it has moved that far in the last 13.7 bn years.

Wasn't all this covered in the very first post in this thread.

25. Originally Posted by m1omg
Why do so many people think observable universe is the whole universe? I see people making claims like "A googol is SO LARGE that it is even larger than the number of elementary particles in the universe" and they always cite the "observable universe" figures to make it seem "universe is really small in fact". There is a very real possibility that the universe might be in fact be infinite (meaning an infinite number of elementary particles so not even Graham's number might actually approach the actual number of particles in the universe anymore than a googol or the number 1 does) and even the accepted cosmology finite universe models generally predict an universe larger than any human idea of infinity - http://en.wikipedia.org/wiki/Orders_...9#Astronomical - the lowest boundary for the size of the universe is 250 billion years and the figure predicted by inflational models is more than 10 to the power of a googolplex - in fact that means that the universe is large enough to have a near-infinite number of cosmological horizons that are exactly the same as ours!

If the latter number is correct, the size of the entire universe is much, much, much higher compared to the observable universe than the size of the observable universe compared to a planck volume.

So no, our universe is not just 93 billion light years big (or 14 billion as some people not understanding comoving distance or the expansion of the universe believe). Our universe is probably so big that it contains a near infinite number of your identical twin, doing the exact same thing as you are doing right now. Now that is humbling.
Please, uniffy the terms...You talk abbout; Whole Universe (=) Actual Universe, Our Universe (=) Observable Universe,...

Then Our Universe (=) Observable Universe seams to be 93 billion light years big(?)= aprox. 10^26 meters

And the Whole Universe (=) Actual Universe could be near infinite or larger than 10^10 ^115 LY (?) ...or the Whole universe's size is at least 10^23 times larger than the size of the observable universe.... then 10^23 * 93 * 10^9 LY= 10^(23+11+15) meters = aprox. 10^60 meters
Last edited by dapifo; 2012-Aug-21 at 09:40 PM.

26. Originally Posted by Strange
The observable universe is currently, I believe, about 46 billion light years in radius; i.e. the stuff that emitted light 13.7bn years ago is now 46bn ly away.

As pointed out at the start of the thread, the whole universe may be be much bigger than that (or even infinite).

Note that even at the current rate of expansion there are objects with an apparent velocity away from us much greater than the speed of light. If the universe is large enough, that has always been true (because relative velocity is proportional to distance).
Wait a minute, how old is the whole universe?

Is it the same age as the observable universe, or older? If older, and if the universe is infinite, is it infinitely old? Is the observable universe like a fairly new, growing fat cell in an immortal and ever expanding morbidly obese person?

27. Originally Posted by SkepticJ
Wait a minute, how old is the whole universe?
Good question. I don't know. I think it is generally assumed to be the same as the observable universe. But I'm not sure we can ever answer your questions.

28. Originally Posted by Strange
Good question. I don't know. I think it is generally assumed to be the same as the observable universe. But I'm not sure we can ever answer your questions.
OK...OK..Now I understand how whole universe could so large..if it older than observable....

29. Originally Posted by dapifo
OK...OK..Now I understand how whole universe could so large..if it older than observable....
Well, it doesn't have to be. I'm not sure why you think it needs to be older to be any particular size? If it is bigger than the observable universe, then I assume it must have always been (roughly) that much bigger than the part that became the observable universe. To take one extreme, if the universe iss infinitely large, then it must have always been infinitely large.

30. Originally Posted by Strange
Well, it doesn't have to be. I'm not sure why you think it needs to be older to be any particular size? If it is bigger than the observable universe, then I assume it must have always been (roughly) that much bigger than the part that became the observable universe. To take one extreme, if the universe iss infinitely large, then it must have always been infinitely large.
During all the thread I was assuming that the Whole Universe starts also in the Big-bang 13,7 billions years ago....then I didnīt understand how it could expand so much (till near infinite).

Now I realize that you accept that is possible that Our Universe started in the Big-bang 13,7 billions years ago....inside other older and larger Whole Universe (!!!)

That is what I have been deffending always ... !!!... and now I understand about the m1omg phrase: "Our universe is probably so big that it contains a near infinite number of your identical twin, doing the exact same thing as you are doing right now.".....That there will be so many (near infinites) bubbles like Our Universe..that it is probabilistically possible that one could exact to Our Universe.

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