I was having a conversation today on the phone with a friend. We got onto the subject of a afterlife and I said that there was probably limitless space. She said nothing was limitless, and that it was proven that the universe has a definite size and is certainly not infinite.

 

I looked this up for a few minutes and couldn't find anything that definitely said the universe it limited. I know there are some rocket scientists and bunches of smart people around so I figured I would ask here.

 

Is the universe limitless? If not then what is the estimated size? Where can I find info on this?

Ky, report to this thread immediately.

I love talking about this stuff. I first want to say that it has not been proven that the Universe is limited, but the general consensus is that it is.

 

The reason it is believed the Universe is limited is due to the fact that space is curved. It is only limited if the Universe is curved onto itself. This would mean that there is enough mass and energy in the Universe that causes all of space to curve onto itself. Currently, we only know about 7% (or about that) of the required mass and energy needed to curve the space enough so that the Universe is curved back onto itself. The other 93% is exotic, or undetectable dark matter.

 

Either that, or Einstein is wrong. There may need to be more physics to explain why some things are happening. Such as the velocity that stars on the outer edges of galaxies orbit the center as fast as they do.

 

But back to the idea that space is limited. So lets assume that there is enough mass and energy so that all space is curved back on itself. This would mean that if you travel in a straight line in space, you will end up back where you started just as if you traveled in a straight line on the Earth, you will end up where you started. The surface of the Earth is a 2-dimensional curved space, so a sphere. The surface of the Universe is a 3-dimensional curved space, so a hypersphere.

 

Space is curved right? According to Einstein. Space is curved around the Sun. So this means that the Earth is traveling in a straight line, but in a curved space created by the mass and energy of the Sun. This looks like an orbit, but in the realm of 3-dimensional curved space, it is not. Now let us build on this idea.

 

Now do you agree with me that traveling at the speed of light, that there is a mass so great that would cause light to orbit around it? Yea, there are things that can cause this, black holes and possibly the Universe itself. A black hole causes this because its curved space is so great, that light just curves back onto itself. Space itself in a black hole is curved back onto itself, but this is in a small area compared to the rest of the Universe. So the Universe must be very massive if a ray of light will bend back onto itself. This is what is believed if the Universe is limited.

 

And there are other problems too if the Universe is infinite. If the Universe isn't limited, and infinite in size, then that must mean that there are an infinite amount of Earths and Suns, and an infinite amount of clones of you, and everything that has already happened, has already happened. If the Universe is infinite, then you have been poor and rich and infinite amount of times somewhere far away a long time ago.

Sweet!! I liked that story.

wow!

 

That was a cool read.

Better watch out for the Klingons near Uranus.

I have to admit that I do enjoy this subject a lot as well, so thanks for bringing it up. In my opinion it might as well be called infinite, as the technology we have will not allow us to travel the curve to verify the theories of our universe. It is amazing to think about what could be...what lies out in that mass expanse of space anyhow.

 

Thus, the debate on the notion of whether there is life or not out there. I tend to side with those that believe there is life out there floating in the sea of darkness. This really hit the spot when you start expanding outward in your view of space and start crunching numbers.

 

It is estimated that our Milky Way Galaxy is around 80-100 thousand light years across (a light year is the distance light travels in a year or around 9,460,730,472,580.8 km a year). This leaves a lot of room for stars to be born, dust to coalesce into clumps, orbits to form around stars and so on...up until you have a solar system. NASA artists have gone so far as to render what is imagined that the Milky Way looks like based on other galaxies here and for reference between a rendered galaxy and a real one...here is our neighboring Andromeda Galaxy here. After looking at the pictures you have to realize that in our Milky Way Galaxy our solar system...is orbiting around a single point of light in that image. Which is one star in what is estimated to be between 200-400 billion stars, with the latter being the best assumption. That is a huge number...a huge number of possibilities as well...just in our own galaxy for life. Life that can range from very simple life forms up to at least one instance of intelligent life that we know of...ourselves. Knowing that there is at least one intelligent life form in our own galaxy, that we know of so far, one can look at Andromeda and wonder what if? Is there life of any form there?

 

Now if we can look at one galaxy with that wonder...then why not look into space and wonder. NASA has done a deep field observation with the Hubble Telescope, where they pointed the Hubble at a single patch of sky at about the width of a dime from 75 feet away for ten consecutive days. The image they got was utterly amazing, here, which shows an amazing number of galaxies from one little patch in the sky. Later the Hubble took what is called the Ultra Deep Field picture of the sky, which was a million-second-long exposure of one spot (here). The UDF goes on to show even more galaxies. Finally...the Hubble program assembled several hundred images into one large expanse of our sky, which they estimate shows some 50,000 galaxies (here). When you start imagining the number of stars in all these galaxies that can be bigger or smaller than our own...and just think of the possibilities...well...I most definitely think we are not alone.

Better watch out for the Klingons near Uranus.

OMG LOL LOL

-I would post an epic tale of the birth and death of stars and the endless darkness encompassing our blip of a galaxy...but it would take much time to write...needless to say...space big...time long...human knowledge little.

-I would post an epic tale of the birth and death of stars and the endless darkness encompassing our blip of a galaxy...but it would take much time to write...needless to say...space big...time long...human knowledge little.

well done!

in freshman year i asked my science teacher where i could find the "Death Star" because we were talking about stars.

 

 

...she rolled her eyes and then talked about a star thats way out there that is referred to as the death star.

 

or something like that

Nice find...notice death star represented

 

THE SIZE OF OUR WORLD

 

THE SIZE OF OUR WORLD II (no death star)

Better watch out for the Klingons near Uranus.

Mine?!?!?!?!?

ok so basically, even if the universe is NOT infinite, it is extremely huge and an area so large could never conceivably be filled up by humans, correct?

From what i understand too the universe is constantly growing.

yea strangely enough i don't understand a word of that stuff

OK just some food for thought . what is to say there is not another universe out there .maybee we are one universe in a series of universes:question:

yeah that was one of my arguments. She said that everything has to have a limit. But then she also said that the afterlife was in another dimension. So my argument was, there is no way you can disprove that another dimension is limitless. Since you cannot go to that dimension while alive, you cannot prove anything about it. Eveything that is true in our dimension could be completely opposite in another dimension.

 

Oh and Nadril that is what I had heard. That would indeed make the universe infinite.