The Depth of the Universe n/a

[mattaxelrod]

I couldn't sleep last night, and my mind started wandering, and I came up with the strangest question....

Is the universe infinite? That is to say, even though the number is incalculably large, are there a finite number of stars and planets, etc.? From my way of thinking, if the universe is expanding, then it must have some quantifiable size, and its contents must be some finite value.

I swear to God, this was what I was thinking about last night at 1:00 am.

Anyone care to chime in?

 

[Frank Browne]

Finite, but unbounded? The Universe has the same general appearence no matter from where you observe it. Or something like that.

http://antwrp.gsfc.nasa.gov/apod/astropix.html

 

[mattaxelrod]

Finite and unbounded are mutually exclusive, no?

And I would submit that the universe has the same general appearance only to those of us who don't know what we're looking at.

Oh my brain hurts.....

 

[Let'sgoflying!]

Is the universe infinite?

Ive had the same thoughts but its been a while. Best done over a couple of beers, fingers fiddling contemplatively with chin, not when trying to sleep!

My favorite answer is, 'no, when you get to the far edges of the u. there is a wall and three doors waiting for you!'

I swear to God

Now you are probably getting closer to a usable answer!

 

[ScottM]

I couldn't sleep last night, and my mind started wandering, and I came up with the strangest question....

Is the universe infinite? That is to say, even though the number is incalculably large, are there a finite number of stars and planets, etc.? From my way of thinking, if the universe is expanding, then it must have some quantifiable size, and its contents must be some finite value.

I swear to God, this was what I was thinking about last night at 1:00 am.

Anyone care to chime in?

#include <stdio.h>

#define SIX 1 + 5
#define NINE 8 + 1

int main(void)
{
printf( "What do you get if you multiply %d by %d? %d\n", SIX, NINE, SIX * NINE );
return 0;
}


"I've always said there was something fundamentally wrong with the universe." -AD
"WE APOLOGISE FOR THE INCONVENIENCE" - GOD

 

[Bill M.]

The only thing finite about the Universe is our ability to comprehend it with linear thinking and imagination.

 

[mattaxelrod]

The only thing finite about the Universe is our ability to comprehend it with linear thinking and imagination.

Agreed. So how can someone state that the universe is expanding when that's such a linear, conventional term?

Expanding means it takes up X space, and now will take up a little more than X space.

 

[mgkdrgn]

Find and buy the old TV series "Cosmos", by Carl Sagan. He does a masterful job of 'splainin these things!

I couldn't sleep last night, and my mind started wandering, and I came up with the strangest question....

Is the universe infinite? That is to say, even though the number is incalculably large, are there a finite number of stars and planets, etc.? From my way of thinking, if the universe is expanding, then it must have some quantifiable size, and its contents must be some finite value.

I swear to God, this was what I was thinking about last night at 1:00 am.

Anyone care to chime in?

 

[kath]

Agreed. So how can someone state that the universe is expanding when that's such a linear, conventional term?

Expanding means it takes up X space, and now will take up a little more than X space.

In the case of the universe, "expanding" means something else. It means that every point in space is moving farther away from every other point at some rate. The universe can be infinite and still do this.

The universe can also have shape or "curvature". (Imagine a spherical balloon expanding, for instance.) However, all the recent evidence from WMAP etc are indicating that the shape of our universe is very close to flat.

From our point of view, the universe appears to have an "edge"... that's the cosmic microwave background radiation. But this is more of a "time" edge rather than a "space" edge... it's 13-someodd billion light-years away (the age of the universe). This is light coming from the first time when light was "free" to propagate through the universe. Another observer in a distant galaxy would observe the same background radiation, at the same distance, in all directions, just like we do.

--Kath

 

[Steve]

You might be interested in reading Fabric of the Cosmos by Brian Greene, or its predecessor The Elegant Universe.

http://www.curledup.com/fabricof.htm

http://www.bookideas.com/reviews/index.cfm?fuseaction=displayReview&id=263

At the sub-atomic and super-galactic realms conventional ideas of physical dimensions become inapplicable in the "real" universe.

http://msnbc.msn.com/id/3077398/

Stars are forming and "dying" continually, so their number is a dynamic value.

The total mass of the universe is a value that has always intrigued cosmologists. The ability to measure it is still something they are working on.

http://csep10.phys.utk.edu/guidry/violence/darkmatter.html

http://www.rostra.dk/louis/quant_11.html

 

[fgcason]

Where were you and your wandering mind a couple weeks ago when this was the only thing I was thinking about for a week straight and everyone I tried to talk to thought I had a week old dead fish on my head?

Finite and unbounded are mutually exclusive, no?

An oversimplified concept is to think of it as a big black hole...from the inside. No matter what you do, you can't get to the event horizon due to inadequate energy available and/or force vector issues. You and anything else, including light, that tries to escape will be turned back into the hole/Universe. IOW no fixed walls that are defineable from the inside due to the wrap around effect near the event horizon. Finite boundaries and finite mass assuming nothing is falling in from the outside however operationally it's unbounded in volume.
Now to add the fun factor: The event horizon/edge of the Universe appears to be some 13-14 billion LY in all directions. No matter where you are in the Universe, the 3°K background radiation should appear to be the same from the same distance.

And I would submit that the universe has the same general appearance only to those of us who don't know what we're looking at.

Agreed within limits.

Oh my brain hurts.....

This should help...or make your brain explode:
http://www.anzwers.org/free/universe/universe.html
And to think that people actually really believe their little money powered touchy feely world is sooooooo important in the big picture...the entire human existence doesn't even qualify as squat nothing dribble. Our entire existence and everything from our meager existence (radio/light emissions) is still contained within about 100 LY of here assuming there's no signal loss.

 

[Frank Browne]

Nice pix Frank! What galaxy is that?

BTW, the attached photo is one that I took several years ago of Comet Hyakutaki. I used a Minolta SLR with a 50mm lens and Kodak Gold 1000 film. It's a 4 minute exposure using a tangent arm platform I built myself.

 

[kath]

http://csep10.phys.utk.edu/guidry/violence/darkmatter.html
http://www.rostra.dk/louis/quant_11.html

Whoa! How did you find this one? I smell "crackpot".
(Beware of anyone on the internet talking about "my theory of the universe", "my cosmology", etc...)

--Kath

 

[mikea]

One model I saw was imagine if you were a dot on the surface of a balloon, looking at another dot, and the balloon gets blown up so you see the other dot move away and it sees you move away and so do all of the other dots.

Then there's the idea that there are unlimited number of universes in the "multiverse*."

*Word courtesy of Q on STTNG

 

[AdamZ]

Along those lines just how many licks does it take to get to the center of a Tootsie Pop?

 

[Steve]

I never said everyone looking for the answer was looking in the right direction...

just that the search was ongoing...

[I listed that one last for a reason]

Whoa! How did you find this one? I smell "crackpot".
(Beware of anyone on the internet talking about "my theory of the universe", "my cosmology", etc...)

--Kath

 

[fgcason]

Nice pix Frank! What galaxy is that?

The first is a HST ultra deep field photo. Just about everything in that photo is galaxies. IIRC it's a classic case of find a dark patch of sky and set the exposure to open-until-further-notice-and-wait kind of thing.

The second is the core of NGC300.
http://www.ngcic.org/dss/dss_n0300.asp

BTW, the attached photo is one that I took several years ago of Comet Hyakutaki. I used a Minolta SLR with a 50mm lens and Kodak Gold 1000 film. It's a 4 minute exposure using a tangent arm platform I built myself.

Very nice.

We put together a 16" scope at school. It took almost a year in the machine shop to build the hardware but we finally got it going. Problem is I moved away right after we got the alignment worked out. A bunch of 5-20 minute tracking error photo's and a couple shots of M42/M43 is about all I have from it.

I'm currently patiently waiting until I have a place to put up an observatory so I can build a 16-18" light bucket. In the meantime, the 60mm refractor I've had forever will have to do on those rare instances when I can find somewhere that's vaguely dark. (I'm seriously thinking the refractor will be used as an off axis guide scope)

 

[tonycondon]

Along those lines just how many licks does it take to get to the center of a Tootsie Pop?

ROFLMAO!

 

[wsuffa]

Along those lines just how many licks does it take to get to the center of a Tootsie Pop?

Shall we bring up the conveyor belt?

 

[Frank Browne]

The first is a HST ultra deep field photo. Just about everything in that photo is galaxies. IIRC it's a classic case of find a dark patch of sky and set the exposure to open-until-further-notice-and-wait kind of thing.

The second is the core of NGC300.
http://www.ngcic.org/dss/dss_n0300.asp



Very nice.

We put together a 16" scope at school. It took almost a year in the machine shop to build the hardware but we finally got it going. Problem is I moved away right after we got the alignment worked out. A bunch of 5-20 minute tracking error photo's and a couple shots of M42/M43 is about all I have from it.

I'm currently patiently waiting until I have a place to put up an observatory so I can build a 16-18" light bucket. In the meantime, the 60mm refractor I've had forever will have to do on those rare instances when I can find somewhere that's vaguely dark. (I'm seriously thinking the refractor will be used as an off axis guide scope)

Light bucket indeed! I bought my oldest son a 10' dob for Christmas and we have thoroughly enjoyed that scope. Very easy to use telescope that works great for casual observing.

 

[fgcason]

Light bucket indeed! I bought my oldest son a 10' dob for Christmas and we have thoroughly enjoyed that scope. Very easy to use telescope that works great for casual observing.

10' ???!!!? If that's your definition of casual observing...


Actually it doesn't take much to have a fun evening out. What most people don't realize is that a dark sky (those are getting very rare nowadays), a seasonal star chart and something surprisingly small with a manual equilaterial mount can keep one happy for years.


Hmmm. I think I'm going to go see if there are any sunspots now.

 

[Dave Krall CFII]

From our point of view, the universe appears to have an "edge"... that's the cosmic microwave background radiation. But this is more of a "time" edge rather than a "space" edge... it's 13-someodd billion light-years away (the age of the universe). This is light coming from the first time when light was "free" to propagate through the universe. Another observer in a distant galaxy would observe the same background radiation, at the same distance, in all directions, just like we do.

--Kath

I don't see how that could be.
It seems if the observer moved a certain distance towards the edge whether it be in "time" or "space" (distance) the background radiation would have to be a proportional amount less.

 

[Frank Browne]

10' ???!!!? If that's your definition of casual observing...


Actually it doesn't take much to have a fun evening out. What most people don't realize is that a dark sky (those are getting very rare nowadays), a seasonal star chart and something surprisingly small with a manual equilaterial mount can keep one happy for years.

You are quite correct. If only more people could realize that those unused binoculars sitting in the top of their closet collecting dust are actually excellent for backyard astronomy!


Hmmm. I think I'm going to go see if there are any sunspots now. [/quote]

Be sure to wear protection! ;-)

 

[SCCutler]

....and thanks for the fish.

 

[ScottM]

....and thanks for the fish.

Glad someone got it.

 

[Dave Krall CFII]

Then there's the idea that are unlimited universes.

I think the idea of the universe/universes should include whatever is beyond any matter contained by them, such as perhaps empty space and time which would appear to be infinite. It could be just as "difficult" for God to have created "nothingness" as anything else we know of consisting of matter.

 

[fgcason]

You are quite correct. If only more people could realize that those unused binoculars sitting in the top of their closet collecting dust are actually excellent for backyard astronomy!

A planisphere, a weak flashlight and a trailpad or blanket is all you really need.

Be sure to wear protection! ;-)

Noooo way! Not going to happen. Protection is for idiots. Vision is too important. I use projection plates only when observing the sun. Direct solar viewing is prohibited at this observatory.

P.S. One dinky sunspot and another ok one. Nothing much or even to bother with the camera but it's better than it has been lately.

 

[jkaduk]

U=1/0

 

[Fast n' Furious]

Time is linear. Space is a curve. Get a light snack, catch a hot shower....get some rest.

 

[kath]

I think the idea of the universe/universes should include whatever is beyond any matter contained by them, such as perhaps empty space and time which would appear to be infinite.

See "quantum field theory." It's mind-blowing stuff. Basically it says that "the vacuum" is the ground state of a quantum field, and that particles (like photons) are just excited states of the same field. All of this can be described mathematically. (How does it feel to know you're just the "exitation of a field"?)

--Kath

 

[Frank Browne]

"exitation of a field"?)

--Kath

Wasn't that a Beach Boys song?

 

[mgkdrgn]

There are a finite number, at any given instant of time, but that number is always changing.

As for how big the number is ... if you go to a beach, and pick up a handful of sand, you'll have about 10,000 grains of sand in your hand. That is roughly the number of stars we can see in the sky with the unaided eye.

The total number of stars in the universe is far greater than the total number of all the grains of sand, on all the beaches on earth.

I couldn't sleep last night, and my mind started wandering, and I came up with the strangest question....

Is the universe infinite? That is to say, even though the number is incalculably large, are there a finite number of stars and planets, etc.? From my way of thinking, if the universe is expanding, then it must have some quantifiable size, and its contents must be some finite value.

I swear to God, this was what I was thinking about last night at 1:00 am.

Anyone care to chime in?

 

[HPNFlyGirl]

oooohhhh la la im seeing stars.

 

[Dave Krall CFII]

There are a finite number, at any given instant of time, but that number is always changing.

As for how big the number is ... if you go to a beach, and pick up a handful of sand, you'll have about 10,000 grains of sand in your hand. That is roughly the number of stars we can see in the sky with the unaided eye.

The total number of stars in the universe is far greater than the total number of all the grains of sand, on all the beaches on earth.

Not really. The all knowing, one true God is too smart to do all that work. All "stars" from about 50 billion miles out from here are just simply painted in with corresponding tint to match expected red-shift.

 

[Dave Siciliano]

How would we even estimate the size of the universe when we have no method in which measure it? Hubble first proved the existence of other galaxies; cataloged seven last I read. We have measured a lot with light, but it has limited speed in the vastness of space. Doppler effect, etc. Hubble proved most galaxies were moving away from us. It is now accepted that the universe is expanding; making it even more vast.

At some point, we must ponder the issue of whether time had a beginning or whether there was a beginning of the universe that can be measured in time. What about the Theory of Relativity only being a partial theory as it does not explain how the universe began.

A lot to contemplate if one can't sleep.

I've read 'A Brief History of Time' by Stephen Hawking several times. Each time I read it, I believe I completely understand it; then, I try to 'xplain it to someone else. Feel like when I was a young man and was going to say all these neat things to my girlfriend. Highly organized in my mind, but when I engaged my tongue, the stupidest things I ever heard began streaming out of my mouth. So.....I shut up.

Funny thing, many years later that lady told me how much she enjoyed hearing those stupid things.

Best,

Dave

 

[Frank Browne]

Hmmm. I think I'm going to go see if there are any sunspots now.

Sunspot activity happening....

http://antwrp.gsfc.nasa.gov/apod/astropix.html

 

[Everskyward]

Sunspot activity happening....

Maybe that's whats screwing with my wireless internet service!

 

[fgcason]

Sunspot activity happening....

There's a lot more really small ones today than yesterday.
When is the next major cycle? 2-3 years?

The 1 marble tour photo valid 5 minutes ago:

 

[Dart]

I couldn't sleep last night, and my mind started wandering, and I came up with the strangest question....

Is the universe infinite? That is to say, even though the number is incalculably large, are there a finite number of stars and planets, etc.? From my way of thinking, if the universe is expanding, then it must have some quantifiable size, and its contents must be some finite value.

I swear to God, this was what I was thinking about last night at 1:00 am.

Anyone care to chime in?

The mass or the space occupied by mass???

The mass is certainly not infinite. Indeed whether or not the current universe can continue to expand or collapse is directly tied to the initial mass it contained.

There is no finite number of stars, planets, etc. as these are born and die on a constant basis. However, neither mass nor energy can be created, only transmutated. So you can have a dark, cold universe with lots of rocks and dust for a very long time, a bright universe of tight knots of very hot particles for a few billion years, , or a very hot universe with no mass and only energy ("Let there be light!") for a really short time!

Since the majority of the mass is unseen (dark matter) the answer is very much in the air. Current calculations seem to indicate an infinite expansion. Then again, when I was in high school quasars were an enigma and black holes a physics "fun with numbers" game.

Right now only God seems to know. He drops hints in his books but, the answer to the puzzle is still very much out there.

 

[Dave Krall CFII]

There's a lot more really small ones today than yesterday.
When is the next major cycle? 2-3 years?

The 1 marble tour photo valid 5 minutes ago:

Why are sunspots darker than the surrounding surface of the sun?