Everyone knows the old hypothetical with the monkeys and the typewriters producing the complete works of Shakespeare. This is similar to that I guess.

Suppose the Universe goes through a cycle of expansion and eventual collapse. Starts with a Big Bang and ends with a return to the point of origin. Every time the Universe is reborn the same galaxies, systems, stars, planets, and moons are formed. This goes on forever. Is it safe to assume that at some point the EXACT same civilization and history will occur? What if the same galaxies, stars, planets etc are not necessarily formed (but they could)? Can you say that eventually all of the same things will happen?

TL;DR how many factors do these hypotheticals rely on? Could you take away all the monkeys with typewriters but one and still have the same result but taking longer?

2/7/2013 1:09:30 PM

Where is that neato story about humanity outgrowing fuel sources with a big computer.... then they combine their conciousness with the computer... then the universe ends... then begins again... etc?

nvmnd... found it.

The Last Question
http://filer.case.edu/dts8/thelastq.htm



[Edited on February 7, 2013 at 1:18 PM. Reason : unrelated to your questions though]

2/7/2013 1:18:04 PM

Quote :

"If our current level of organization, having many self-aware entities, is a result of a random fluctuation, it is much less likely than a level of organization which only creates stand-alone self-aware entities. For every universe with the level of organization we see, there should be an enormous number of lone Boltzmann brains floating around in unorganized environments. In an infinite universe, the number of self-aware brains that spontaneously randomly form out of the chaos, complete with false memories of a life like ours, should vastly outnumber the real brains evolved from an inconceivably rare local fluctuation the size of the observable universe."

http://en.wikipedia.org/wiki/Boltzmann_brain

http://en.wikipedia.org/wiki/Spontaneous_order

2/7/2013 1:41:41 PM

http://www.huffingtonpost.com/2012/10/03/universe-expanding-spitzer-space-telescope-data_n_1937474.html

Quote :

"By: Clara Moskowitz Published: 10/03/2012 05:33 PM EDT on SPACE.com The universe just got a new speeding ticket. The most precise measurement ever made of the speed of the universe's expansion is in, thanks to NASA's Spitzer Space Telescope, and it's a doozy. Space itself is pulling apart at the seams, expanding at a rate of 74.3 plus or minus 2.1 kilometers (46.2 plus or minus 1.3 miles) per second per megaparsec (a megaparsec is roughly 3 million light-years). If those numbers are a little too much to contemplate, rest assured that's really, really fast. And it's getting faster all the time."

2/7/2013 1:43:46 PM

distance/time/distance

that is a unit of distance^2/time

I do not comprehend. What am i misreading here?

2/7/2013 1:54:49 PM

These wikipedia articles...

"I miss the future, where brains flew through space, and everyone ate lasers"

2/7/2013 1:59:32 PM

Quote :

"distance/time/distance that is a unit of distance^2/time I do not comprehend. What am i misreading here?"

I think what it is saying is that every 3 million light-years the expansion speed increases by 46 miles per second?

2/7/2013 2:01:57 PM

but seriously, the universe isn't likely to end in a big crunch.

2/7/2013 2:06:01 PM

If the expansion/contraction occurs for eternity as described in the OP then every possibility will occur an infinite number of times, right?

2/7/2013 2:12:51 PM

Well, the universe will never contract, so no.

But just look at quantum many-worlds interpretation. Basically, if you accept that (such that there never is any decoherence, collapsing of the wavefunction), then the existence of "our" universe is only defined by likelihood. The versions of the universe are infinite, and the ones that appear to make sense classically just outnumber the ones that don't.

2/7/2013 2:37:07 PM

No....nonono. I am not saying this is ACTUALLY how the Universe will end. This is a hypothetical question. Regardless, if the universe is reborn for eternity no matter how it dies, the question remains.

2/7/2013 2:46:23 PM

God damn infinite monkey theorem almost got me fired at my last job

2/7/2013 2:48:11 PM

Quote :

"I think what it is saying is that every 3 million light-years the expansion speed increases by 46 miles per second?"

light year is a unit of distance....

2/7/2013 2:49:11 PM

^ yes I know.....



edit: think of each point 3 million light-years apart with the rate of expansion increasing by 46 miles per second every successive point



[Edited on February 7, 2013 at 2:55 PM. Reason : .]

2/7/2013 2:50:18 PM

so what did you mean by that?

did you mean that after every distance of 3 mil LY, the expansion rate increases by 46mi/s? if so, starting from where, the center of the universe? i guess that kinda makes sense.

but that also means that for a distance of 3 mil LY, the expansion rate is constant, and then for the next 3 mil LY chunk, the rate is suddenly different, and so on. that is weird.


[Edited on February 7, 2013 at 2:53 PM. Reason : ]

2/7/2013 2:52:17 PM

Quote :

"This is a hypothetical question. Regardless, if the universe is reborn for eternity no matter how it dies, the question remains."

"reborn" isn't really a good approach. Even physicists agree (in spite of being virtually allergic to the topic) that an evolutionary mode of universe progression would be more useful than a cyclical one.

The problem with rebirth is that it's still linear. Sure, you could imagine an infinitely repeating universe that goes through many possibilities, but if you add in branching you have "more" possibilities than that. Plus, you need containerized constraints. The laws of physics are pretty damn consistent, so changing the rules leads to different sets of infinities. There may be sets of laws that categorically prevent the emergence of life. The conventional view of infinity is pretty ho-hum in comparison.

2/7/2013 2:53:56 PM

Any view of infinity is ho-hum by comparison of the "real" thing.

I see your point though. I tried to edit the original post but it has already been 30min

Quote :

"but that also means that for a distance of 3 mil LY, the expansion rate is constant, and then for the next 3 mil LY chunk, the rate is suddenly different, and so on. that is weird."

Well, the expansion rate doesn't have to be in steps like that. It could be gradual.

[Edited on February 7, 2013 at 3:04 PM. Reason : blah]

2/7/2013 2:59:18 PM

I'm a fifth-year math grad student specializing in probability. And just to weigh in with my nerdy opinion...

Quote :

"If the expansion/contraction occurs for eternity as described in the OP then every possibility will occur an infinite number of times, right?"

Not necessarily. It really depends on the structure of the random variable that governs the Universe's configuration.

Consider it this way. If you flip an ordinary coin infinitely many times, then you're going to get infinitely many heads and infinitely many tails. But suppose that instead of a regular coin, you've got a coin which, when flipped, gives you a random real number. Then you could flip that coin infinitely many times and never get the same number twice, because the real numbers are "uncountable" (technical term) and you're only flipping the coin countably many times.

So it really depends on whether the number of possible states of the universe is countable or uncountable (and I don't think anyone knows this.) If there are only countably many states, then the Universe will repeat itself infinitely often. But if there are UNcountably many states, then the universe will NEVER repeat itself, i.e. this particular state of the Universe will never arise again, even if infinitely many cycles happen.

The monkey with a typewriter is a case in which the number of possible outcomes is countable (and indeed, finite) so we do get infinitely many repetitions.

Also,

Quote :

" Could you take away all the monkeys with typewriters but one and still have the same result but taking longer?"

Yes, definitely. You only need one monkey.


[Edited on February 7, 2013 at 8:23 PM. Reason : oijp]

2/7/2013 8:20:20 PM

Eternity is like, a long time.

2/7/2013 8:25:55 PM

^^yes/lol

also

Quote :

"but that also means that for a distance of 3 mil LY, the expansion rate is constant, and then for the next 3 mil LY chunk, the rate is suddenly different, and so on. that is weird."

I think the assumption is correct, but you must take into account that the measurements of such things as infinite expansion upon infinite space make for uncomfortable quantifying, and that the rate given is almost certainly a "good enough for the audience" version. So an untold amount of information is being omitted.
Just be glad they didn't do a "football field" or "empire state building" comparison.



[Edited on February 7, 2013 at 8:28 PM. Reason : fas]

2/7/2013 8:27:45 PM

Quote :

"http://www.huffingtonpost.com/2012/10/03/universe-expanding-spitzer-space-telescope-data_n_1937474.html By: Clara Moskowitz Published: 10/03/2012 05:33 PM EDT on SPACE.com The universe just got a new speeding ticket. The most precise measurement ever made of the speed of the universe's expansion is in, thanks to NASA's Spitzer Space Telescope, and it's a doozy. Space itself is pulling apart at the seams, expanding at a rate of 74.3 plus or minus 2.1 kilometers (46.2 plus or minus 1.3 miles) per second per megaparsec (a megaparsec is roughly 3 million light-years). If those numbers are a little too much to contemplate, rest assured that's really, really fast. And it's getting faster all the time."

Quote :

"distance/time/distance that is a unit of distance^2/time I do not comprehend. What am i misreading here?"

this is just a more accurate measurement of the Hubble Constant.

The Hubble Constant is a measurement of the rate at which the universe is expanding. We know that the more distant an object is from us, the faster is is receding from us.

The units simply mean that an object that is 1 megaparsec away from us is receding from us at 74.3 km/s.

An object 2 megaparsecs away from us is receding from us at 148.6 km/s, etc...


[Edited on February 7, 2013 at 8:37 PM. Reason : /]

2/7/2013 8:35:54 PM

distance/(time/distance)

that is a unit of distance^2/time




(distance/time)/distance

that is a unit of 1/time

2/7/2013 10:05:49 PM

right. the SI units of the Hubble Constant are s^-1

multiply the Hubble Constant by km/megaparsec, take the reciprocal and you're left with the age of the universe in seconds.

1 megaparsec is 3.086×10^19 km

(74.3 km/s/Mpc) * (3.086×10^19 km/Mpc) = 2.408×10^-18 per second

1/(2.408×10^-18 per second) = 4.152 × 10^17 seconds

(4.152 x 10^17 seconds)/((60s/min)*(60min/hr)*(24hr/day)*(365.25day/year))

= 13,156,894,060 years

TA-DA!

[Edited on February 7, 2013 at 10:28 PM. Reason : way better than the state game]

2/7/2013 10:27:38 PM

TA-DA!!!!

2/7/2013 11:17:23 PM

It's completely counter intuitive and mind blowing that the universe is expanding at the seams. No religion ever has come close to capturing how amazing the world really is.

But regarding the original post, I don't think things
Recreate the same way each time. When things crunch back, they exist in quantum states that you can't predict exactly how they will reexpand from.

2/7/2013 11:43:17 PM

Maybe I should create a different hypothetical in which time is reset at the dawn of the human race an infinite number of times (or maybe not). Forget about quantum states and the rules of physics for a minute. This is strictly a mathematical question, even though I do enjoy all the discussion about cosmology and astrophysics.

2/8/2013 12:02:40 AM

Quote :

"It's completely counter intuitive and mind blowing that the universe is expanding at the seams. No religion ever has come close to capturing how amazing the world really is. "

Indeed.

Yo Mo'ron what up mane.

2/8/2013 12:10:54 AM

Quote :

"right. the SI units of the Hubble Constant are s^-1 multiply the Hubble Constant by km/megaparsec, take the reciprocal and you're left with the age of the universe in seconds. 1 megaparsec is 3.086×10^19 km (74.3 km/s/Mpc) * (3.086×10^19 km/Mpc) = 2.408×10^-18 per second 1/(2.408×10^-18 per second) = 4.152 × 10^17 seconds (4.152 x 10^17 seconds)/((60s/min)*(60min/hr)*(24hr/day)*(365.25day/year)) = 13,156,894,060 years TA-DA!"

see, this is really cool stuff to me. but I have yet to wrap my brain around the concept of a reciprocal second. I am just now taking gen chem 1 this semester. How I've described their new measurement of the cosmological constant; is that a way to think about the idea of 1/s?

2/8/2013 12:22:49 AM

technically 1/s is the SI unit for frequency...Hz, and is defined as the number of cycles per second of some periodic phenomenon.

it isn't useful to think of the hubble constant in terms of cycles per second, at least not that i'm smart enough to think up (but i'm no cosmologist, so...)

It's useful to think of the Hubble Constant in terms of (km/s)/Mpc, as already described, when thinking about the expansion of the universe. It's useful to think of it in terms of 1/s when thinking about the age of the universe.

By the way, the cosmological constant is something totally different from the Hubble Constant and hasn't been discussed in this thread yet.


[Edited on February 8, 2013 at 9:56 AM. Reason : l]

2/8/2013 9:54:10 AM

Quote :

"Could you take away all the monkeys with typewriters but one and still have the same result but taking longer?"

Yes, and it would still happen an infinite number of times

2/8/2013 2:55:03 PM

Yeah I don't see the point in having an infinite number of monkeys.

Also, what if the monkey just presses the Q key for all eternity? He could have OCD.

2/8/2013 2:58:01 PM

2/8/2013 3:46:34 PM

Quote :

"Also, what if the monkey just presses the Q key for all eternity? He could have OCD."

I think the theory depends on the monkey hitting keys randomly so that all keys have an equal chance of being hit with each keystroke.

2/11/2013 8:27:28 PM