Impossible to answer?

[ledwix]

Re: Impossible to answer?

Actually, the curvature of the universe is not a term relating directly to the geometric shape of it, if I recall correctly. It refers to something regarding the average matter/energy density of the universe. A flat universe is one in which the mass/energy density hovers or stays very close to a critical value and therefore, once the cosmos reaches a maximum size, all expansion stops, and the universe stays the same size for the rest of eternity. Curvature can be either positive or negative. Positive curvature implies that the mass/energy density of the universe is higher than some critical value, and therefore, there is enough mass in the universe to make it collapse back into itself after a certain point. Negative curvature implies that the initial expansion forces and the cosmological constant propel the universe outward forever, as the forces of gravity drop off and become too weak compared to the cosmological constant. Under this scenario, the universe expands forever.

I believe the term curvature itself is used because of the way gravity (i.e. mass) causes curvatures and distortions in spacetime according to relativity.

[StyleKrong]

Re: Impossible to answer?

There are so many different answers you can give to a question like this. Really, the only correct answer is the one you accept.

If you want an answer to what the white on the paper is, well, it's blank. Maybe that part of the universe hasn't been created yet?

If you want to go outside the box, you're holding that piece of paper. What is everything outside that piece of paper? What you're asking is to define the unknown... which is, as you said, "impossible to answer", unless you commit yourself to believing a single answer which you perceive as being true.

One theory I'm fond of is that outside of the expansion of the universe is simply energy, or force. Eventually, when the universe loses the propulsion from it's initial explosion, this force will slowly push the universe back upon itself. Essentially, when the universe stops expanding, it will de-expand, and eventually collide with itself once again, causing another big bang, and thus, eternal existence is born.

[dsliscoo]

Re: Impossible to answer?

Actually, the curvature of the universe is not a term relating directly to the geometric shape of it, if I recall correctly. It refers to something regarding the average matter/energy density of the universe. A flat universe is one in which the mass/energy density hovers or stays very close to a critical value and therefore, once the cosmos reaches a maximum size, all expansion stops, and the universe stays the same size for the rest of eternity. Curvature can be either positive or negative. Positive curvature implies that the mass/energy density of the universe is higher than some critical value, and therefore, there is enough mass in the universe to make it collapse back into itself after a certain point. Negative curvature implies that the initial expansion forces and the cosmological constant propel the universe outward forever, as the forces of gravity drop off and become too weak compared to the cosmological constant. Under this scenario, the universe expands forever.

I believe the term curvature itself is used because of the way gravity (i.e. mass) causes curvatures and distortions in spacetime according to relativity.

uhm critical mass of one is a flat universe that will not expand or contract. Below one and the universe will expand and >1 and it will eventually expand to far to the "big chill". I am fairly certain they don't use gravity to figure out what that number is, because the known gravity in the universe pales in comparison to the energy that should be in this universe for it to be as close to one as it is.

in case that doesnt make sense...

1 = flat universe/not changing
<1 = expanding forever
>1 = contracting
our universe ~= .05 - .2(known mass)
our universe is supposed to equal somewhere really close to 1. (10^15 decimil places)

The way i was reading the measure of curvature was talking about the actual shape of the universe not really the distances between points in space and whether or not they are getting closer or farther from each other.
If they were trying to measure that a laser wouldn't work. Two things would probably happen. Either light would appear to speed up because the space has shrunk(or slow down if it has grown) or more then likely the effects wouildn't be measureable with them.

Either way, i really don't think the universe is expanding or cointracting I think the universe has been this way for a very long time.

[OneHandNow]

Re: Impossible to answer?

1 = flat universe/not changing
<1 = expanding forever
>1 = contracting
our universe ~= .05 - .2(known mass)
our universe is supposed to equal somewhere really close to 1. (10^15 decimil places)

I've heard of this before! It was in a book written by a (devout?) atheist (forgot his name--but he is a famous physicist in India) and also related to the fact that it is almost impossible for a universe to have this value so close to 1, that either 1) only some omniscient being could make this seemingly "perfect" universe 2) or we just got really lucky .. which is probably not the case..

So this made me think for a bit because I am an Atheist myself, but I am thinking of becoming an Agnostic :P It surprises me how "lucky" our universe or "Earth" has been throughout the years -- I mean.. are we the only ones alive? Or are there others? ><

[Froston]

Re: Impossible to answer?

The only thing keeping the big bang theory a theory is the fact that us people; scientists have not found a location at any proportion/scale where all the forces function together comfortably.

The big bang theory can be a stepping stone to understanding complexities of the universe we never would have reached without the curiosity to know the truth.

When it comes down to mathematicians, physicists, scientists etc.. Theories can be proven on one of those terms but it is not absolutely true until it is proven on every system.

i.e. I've seen a documentary on the universe where it was proven with deep math that if you take a point in the universe, any point and fold it, there will be another universe. Discoveries like these always flood our minds because they are new pieces of information and to know is a great feeling, but this is something proven on the mathematical system only and may as well be 1 point over worthless.

Ignorance is avoiding reality; to learn is part of reality and to believe or imagine is a higher power that can make or break you. A lot of famous physicists and scientists also believe in a god. Logically if you're given the opportunity to believe then why not take it. Personally I stand for knowledge and secondly for what I don't know I can trust with belief, or have "faith" in that thing.

Knowledge is said to be the food for the soul, and it is the most powerful and valuable ability. If you've read this post then you can clearly tell I'm pretty philosophical, and I feel that if I were to share my opinions on the universe it wouldn't enlighten most of you as much as what I've just wrote here on this post.
I'd also like to say that our fascination with the universe is practically infinite, and so so should the fascination with human life be. There are many things in the universe that have not ever existed, that we have made, on our little planet where the atmosphere extends up for about only 100km.

Happy thinking, pce.

[ledwix]

Re: Impossible to answer?

uhm critical mass of one is a flat universe that will not expand or contract. Below one and the universe will expand and >1 and it will eventually expand to far to the "big chill". I am fairly certain they don't use gravity to figure out what that number is, because the known gravity in the universe pales in comparison to the energy that should be in this universe for it to be as close to one as it is.

in case that doesnt make sense...

1 = flat universe/not changing
<1 = expanding forever
>1 = contracting
our universe ~= .05 - .2(known mass)
our universe is supposed to equal somewhere really close to 1. (10^15 decimil places)

This is almost exactly what I said, except that what you mean when you say "1" is that the ratio of average mass/energy density to the critical value is 1. When you say critical mass, this implies gravitation is used to measure curvature, as mass is the origin of gravity.

[richy:]

Re: Impossible to answer?

Ignorance is avoiding reality

I believe it was Thomas Gray that said "where ignorance is bliss, 'tis folly to be wise."

Reality can be kind of painful. Unless you are going to be a astronomer or physicist or something it is probably better to just believe what you want to believe because you will never find any true answers. Sure there is nothing wrong with looking, but when it consumes you, all you are left with is an empty feeling. I think this is a reason a lot of people turn to religion, and end up being much happier.

[Reach]

Re: Impossible to answer?

With respect to the curvature of the universe, you have to be really careful here. When we say the universe is flat, we mean Euclidean - i.e. two straight parallel lines will never cross, angles within a triangle always equal 180 degrees etc. In curved spaces, this isn't the case (For example, if you draw a triangle on the surface of the Earth the angles won't equal 180 degrees).

Most of the misunderstanding of this concept comes from us picturing flat as a piece of paper. This is not really the case with the universe. When we say the universe is flat, we are saying it is 3 dimensional flat space. It's quite easy to describe mathematically, and you can test it, as probes like WMAP have done to determine the universe is in fact flat space!


This tells us more about the topology of the universe though than it's global structure or 'shape'. This is not currently known. It could be anything. Some people even suggest it looks like a cone.

[rushyrulz]

Re: Impossible to answer?

Just my 2 cents.

If the answer is NOTHING, the big bang theory is false. If there's nothing, it can't be expanded into, thus a highly concentrated "bead" of matter can't explode or stretch whatever you want to call it anywhere.

so since we've all been wtfbigbanging so far in this thread, lets turn to the oscillation theory which states that the universe is kind of 'breathing,' we're just on a really big inhale right now so we think that we're expanding forever. It could start shrinking any time now =D.

Another question I'd like to propose.. What would happen if we got to the edge of the universe? Do we knock on it and a bunch of space monkeys pop out and dance and say you won the game, or does your hand pop out on the other side of the universe?

Since I've pretty much said that there can't be nothing, alloyus's proposal isn't as frivolous as it seems. Nobody has gone to separate edges of the universe and thrown crap through the walls yet so we don't know the answer to this question. To put a visual in your mind, here's a video:

http://www.youtube.com/watch?v=dSb0PsNq9ao

skip forward to 16:20 through 16:40.

The example is inverse. The universe would be the inside and it would be like they were running out and ending up on the other side of the dome.

We don't know the answer because we've never been to the edge of the universe.

[richy:]

Re: Impossible to answer?

http://www.youtube.com/watch?v=dSb0PsNq9ao

skip forward to 16:20 through 16:40.

I always thought yugi-oh might hold the answers.
Here is a video that I find relevant:

http://www.youtube.com/watch?v=YAXJZj_NXUQ

[rushyrulz]

Re: Impossible to answer?

lol, my example just so happened to be in Yu-Gi-Oh, but it's a good visual for what I'm talking about.

[alloyus]

Re: Impossible to answer?

alloyus's proposal isn't as frivolous as it seems.

Orly?!

[MrRubix]

Re: Impossible to answer?

Some concepts don't seem intuitive at first because we're used to certain exposures. For instance, the types of speeds we witness here on Earth are slow compared to the speed of light, and so the concept of relativity would seem strange at first. Much like we're used to the idea of something expanding INTO something, we would find the idea of nothingness strange. But that's simply what it is -- there is nothing outside of the universe.

[dark-juju]

Re: Impossible to answer?

Humans always have to think that everything happens on a time line. Don't really feel like elaborating on this because its mostly irrelevant to the rest of my post.
As for the 'Asteroids' theory, I support this, although I believe it to be more of an infinite loop. I.E. In the game Asteroids, if you move laterally into one border, you will come out in the exact same spot on the opposite side. Now, in order for this to be true for the universe, we have to apply this theory in (at least) 3 dimensions, since we DO NOT exist in 2 planes of reality, we exist in 3(or 4, or more, who knows, whatever, not relevant to my post). At least, these are the dimensions that we can so far comprehend. SO if we apply the 'Asteroids Theory' to 3 dimensions, we can assume that any object traveling one direction will (eventually) emerge on the exact same location, on the exact opposite side of the universe. But what is there, at that boundary you reach just before you pop out on the other side? I don't believe its 'nothing' as so many people have stated, simply that its connected to that part of the universe that you end up, after reaching that 'border.' Only, the 'border' is non-existent, as every part of the universe is connected to to the spot on the exact opposite side of the universe. This is where the 'infinite loop' comes in. Say you're moving west on earth, eventually you will end up in the same spot you left from. Now, take that same theory, and rotate that plane and copy it an infinite amount of times, So that no matter what direction you traveled, if you kept going in a straight line, you WILL eventually end up where you started. If you apply this to the universe, then there would truly be no 'outside' the universe, thus, no need to question 'what is outside the universe?'

[bobeck2]

Re: Impossible to answer?

Well, the answer is not currently known.

I think that pretty much sums it up. Every other attempted answer to the question is only speculation or an application or reiteration of a possibly correct theory to which no definite answer can be derived from. Human knowledge is finite. I'm not saying we will never know, it's just that currently we havent the means to know. On a second thought, what is the importance or practicality of this question?