Math Question I need your help!

How do we define the universe? Is it the dimensions of infinite void that contain matter? Or is it the size of the void? WHat shape is the void, do we assume it's a sphere since WE would create the universe as a sphere if it were up to us?
How do we know where the center is? Is the center of the universe High Falls, NY? How do we know we are observing the actual edge? Maybe the matter is in the shape of an expanding HOLLOW sphere, and all we see is what's before the horizon? If that's the case, I guess we are prone to the same errors no matter how large our realm of observation. How big did we think the earth was 500 years ago? what shape was it? Flat? oh really. Now we know how big the universe is? I bet the freakin aliens that buzz our planet don't even know how big the universe is.

I love it when they post this crap on CNN, like they know how big the universe is. They should stick to reporting their DIRECT observations, instead of trying to tell us some planet hundreds of light years away has an earthlike atmosphere, then you read into it and they drew that conclusion because the image "wiggles"

Originally posted by masterp

Originally posted by GavCg

Originally posted by Physicsrus
Sorry, but you all are confusing yourselves. Let's start with the basics.

The universe is infinite.
The universe is homogeneous.
c (speed of light) is constant at 300,000,000 m/s

i would like to know where/how/prove/why the universe is 1) finite


[edit on 17-1-2008 by GavCg]

If it was infinite, then the cosmic background radiation would not exist. Since CBR exists, then there was a big bang, therefore the universe is finite.

a finite model would place a limt and range on the size/volume, albeit the universe is constantly expanding [ theoratically]. and that would also mean nthere has to be something greater in size for it to exist in.
if you say its finite then i would like to know how, and for you to prove why. CBR is not relative enough to be reason or cause.

a finite model would place a limt and range on the size/volume, albeit the universe is constantly expanding [ theoratically]. and that would also mean nthere has to be something greater in size for it to exist in.
if you say its finite then i would like to know how, and for you to prove why. CBR is not relative enough to be reason or cause.

the same could be said of your infinite model, prove that it's infinite, latest research from the WMAP probe suggest that the universe is in actuallyity infinte but that doesnt mean that it is and how long till our understanding of it evolves and the universe is actually flat! or very close to it! im actually amazed at that one!
map.gsfc.nasa.gov...

[edit on 17-1-2008 by Fada126]

[edit on 17-1-2008 by Jbird]

It's actually quite simple. Your formula only accounts for the y axis, but the universe is 3 dimensional (physically). Add the x and z axis to your equation. Also, there are many different size of galaxies, so you are making a big assumption using the Milky Way as your 'average' model.

Baiscially to answer your question on a one dimensional basis, and assuming the universe is circular, you would take the radius of the universe and square it to get the area of the universe. You would then to calculate the area of our solar system using the same methodology.

Assuming that the universe is 14.5 billion light years wide then you would have a radius of 7.25 billion. So square 7.25 billion and you get some number that I dont know the name of: 523,812,400,000,000,000,000 light years. This the area of a one dimensional cirular universe 14.5 billion light years wide.

Our solar system is 50,000 light years wide?, if so, then you would square 25000 light years, which gives you the area of our solar sytem of
6,250,000,000 light years.

Next divide 523,812,400,000,000,000,000 by 6,250,000,000 and you get
83,809,984,000. So give or take you could get 83-84 billion of our solar systems in such a universe.

Of course the universe is not one dimensional and most likely not perfectelly circluar either. Since we don't know we really can't solve your problem.

Originally posted by hereticalmind
If the milky way galaxy is 100,000 Light yrs in diameter,

Keyword IF. News flash, its not.

Originally posted by hereticalmind
and the universe is 14.5 billion lights yrs

WRONG. PLEASE don't think theorys are true. That is the problem with this world, and science. You are basing your calculations on NOTHING TRUE.

Originally posted by ALLis0NE

WRONG. PLEASE don't think theorys are true. That is the problem with this world, and science. You are basing your calculations on NOTHING TRUE.

well, its easy to dis-credit theories, however, in the same light you can t prove them false either. you cant prove the universe is "x" billion light year old and nor refute that with anything else.

reply to post by GavCg


Actually I have solid proof that no man or craft has ever reached the end of the universe to tell us it's distance.

Heck, we haven't even reached the center of our Earth to prove it has an iron core, yet you all believe that b.s. too.

[edit on 17-1-2008 by ALLis0NE]

Okay, back around 1980 or so a book came out by Timothy Ferris. Here is the problem. First of all, if only using light wavelengths you are only looking at kind of a cone of light that you can only make out to be as far back as 14.5 billion years ago and actually now measured by other wavelengths like microwaves. That the background radiation just above Absolute Zero was found by AT&T Bell Labs by Wilson and someone else was the microwave background measured all around no matter where they looked. That becomes the Age of the Universe, but even at that, nowadays I think they think that the Universe is sort of flat more than spherical something like the Milky Way Galaxy. More like a brane membrane than anything like a Planet -- or basically more flat then anything else. Of course there is a thickness also with that flat but they keep making measurements to keep coming up with more theory. I guess I am not explaining it very good, but in the end the measuring intruments that they use may get more sensitive but still they still pick up more of the universe, and I am not sure if there is a calculation after finding the background radiation of the Universe, simply because I think they can not make a measurement to know for sure. The only way that they make measurements to the stars is to find stars that are like candles that they can measure the brightness of and determine other stars by those candles and measuring guide type stars. Usually I think they have use Cephoid type Stars to measure things.

In other words, you may pick up radiation of the background but actually you can not make a measurement to any of it, all you could do is guess, and you do not have a yardstick to come up with anything but a guess to it.

So you can come up with an Age only and not a measurement that becomes a yardstick, only a guess. I think without actually going out into SpaceTime and actually getting something more accurate it will only be an educated guess, and perhaps anymore they are looking more at structure of the Universe than trying to determine a measurement of the size of the Universe.

All they can state is that the Hubble Telescope has seen hundred of billions of galaxies in a wide field camera shot of the Universe. That is still a guess but a little more of a guess because they can estimate a little more then.

reply to post by redmage


Once you have the value for width, height and length, you'd have to cube it to get the total amount of galaxies (roughly).

so, 145,000 x 145,000 x 145,000 = 3,048,625,000,000,000

EDIT: That is assuming the universe is a cube, but it is more than likely spherical, so different maths, but an equally huge number, would be used.

[edit on 18/1/08 by stumason]

Originally posted by hereticalmind
I am having a problem figuring out this equation. It is probably very simple maybe someone can help me.

If the milky way galaxy is 100,000 Light yrs in diameter, and the universe is 14.5 billion lights yrs that only leaves room for 145,000 milky way sized galaxies.

I realize most galaxies are probably smaller(some larger) but scientist claim there may be hundreds of billions of galaxies.

Where would they all fit?

If the Universe is 14.5 billion light years across (which I personally don't believe, I think it's a lot bigger), if you take the volume of the universe (LxWXH), you get a total volume of 3.049e^30 cubic light years.

If you take the volume of the Milky Way Galaxy, 100,000 light years (a figure I also think is BS), you get a total volume of 1e^15 cubic light years.

To find how many Milky Way Galaxies the Universe can hold, divide the volume of the Universe by the volume of a single Milky Way Galaxy.

That's:

3.049e^30 cubic light years
1e^15 cubic light years

That gives you a grand total of 3.049x10^15 Milky Way Galaxies that could fit inside the Universe. What does that number look like?

3,048,630,000,000,000 Milky Way Galaxies could fit inside the Universe. That's over 3 QUADRILLION Milky Way Galaxies, assuming I didn't make a silly math error writing this post in 2 minutes

Now, let's realize a few things:

The Universe may not be cubic, it may be spherical, or more likely, elliptical. Also, and here's the biggie, that's ONLY THREE DIMENSIONS. All signs point to there being many, many more dimensions than three. There could be so many other dimensions, the volume of the Universe could increase a quadrillion times over or more. Imagine that all we can perceive is 1% of the Universe or smaller

Funny thing is, this is really one of the most conservative estimates out there. Mindboggling!

[edit on 18-1-2008 by ChocoTaco369]

post by stumason[/url]
Once you have the value for width, height and length, you'd have to cube it to get the total amount of galaxies (roughly).

so, 145,000 x 145,000 x 145,000 = 3,048,625,000,000,000

Almost. As I said earlier, the Milky Way is much thinner than its diameter, so you could still "stack" far more than 145,000 on top of one another.

However:

post by stumason[/url]
EDIT: That is assuming the universe is a cube, but it is more than likely spherical, so different maths

Exactly, L*W*H doesn't give you the volume of a sphere, so you'd need to use a different equation.

[edit on 1/18/08 by redmage]

Yeah, their not even sure that the universe is sphere, so you can't make those calculations .. Heck, the universe could be shaped like a cylinder, and bent into a loop, to form a never ending ring. And we are moving through the ring like electrons in a wire, spinning... How do you calculate that? You need measurements that you can't get with a "beam". You can't get the circumference....

[edit on 18-1-2008 by ALLis0NE]

ok if your serious about doing this math formula

im sure we can (mostly all) agree that the universe would be a Sphere shape.

so lets use formula's for a sphere

The surface area of a sphere of radius r is

A = 4pr^2 ((((p = Pie because i dont have a button for it))))



Volume = 4/3 pr^3


according to standard model we have Radius
so plug it in and do the math... if ur interested

Originally posted by muzzleflash

im sure we can (mostly all) agree that the universe would be a Sphere shape.

I dont think the universe is a sphere cause then it would be finite wouldn it? and would have to be contained by something.And is according to latest readings from wmap actually flat, looks like the medieval lads were on to something, they just wern't thinking big enough!
This link will explain all!
map.gsfc.nasa.gov...

Whatever your calculation, formula, equation, is... I'm almost 100% certain your answer for now will be ∞.

en.wikipedia.org...

reply to post by hereticalmind


Hi hereticalmind. Your calculation is wrong in a few places! First is age- the Universe is 14.5 billion years old! It is actually something like 93 billion light years to the Event Horizon. You see, according to Cosmological models, when the Universe formed there comes a time from your point in an expanding Universe when the light from distant objects can't reach you anymore, this forms a shpere of visibility around the observer called a horzion.

Thick of it in terms of the expanding ballon. Imagine you cover the ballon with dots. As you blow the balloon up the dots spread out from each other. If the balllon was large enough there would come a time when you couldn't see the far dots anymore. They still exists and there's a lot of space still there, you just can't see it anymore.

Just to add to the confusion, when we talk about the expanding universe, it is the spacetime in between galaxies which is expanding, we call it Hubble flow. Now where the energy driving the expansion of the Universe can be traced to is a quantity called the Cosmological constant, which I belive according to quantum field theory in curved spacetimes, may come from vacuum fluctations.

Hope this helps,

-Paul.


[edit on 21-1-2008 by timelike]