How Big is the Universe

[theTribster]

I knew it was bigger then it is old but I didn't realize the extent of the difference. As usual the 'standard' theories have wildly different predictions ranging from 92 billion to over a billion trillion light years across. The standard theories include BBT+variations of the inflationary model.

 

The WMAP data, according to several researchers shows that the Universe is no less than 156 billion light years across with a maximum of 10x10^24. This means the visible Universe ridiculously small regardless of the prediction.

 

I know that measuring various rates of change in standard candles (Supernovae) has caused some of this expansion in thinking. Still seems as though a more complete understanding of Quasars will shed more light (pardon the pun) on the size (and age) question.

[fluid]

Universe is expanding, and it is accelerating also. this has led to the big rip theory, basically that the universe will start to expand so fast that all matter get ripped apart because of the expansion.

 

I know the size of the universe is actually to big to actually think of cause we are so small.

 

Look at 'Hubble Deep Space', search it up in youtube, you might find it interesting

[HydrogenBond]

Although the space-time of the universe is expanding, many things in the universe routinely cause local space-time to contract. For example, a forming star pays no heed to an expanding universe and can cause local space-time to contract. The black hole even causes local space-time to contract, all the way to the limit, and continues to add matter and contract more space-time.

 

I often wondered whether because stars, black holes and other structure, by using mass-gravity to contract space-time, is more potent than universal space-time expanding using ethereal dark matter? I don't see stars no longer willing to form.

 

The EM, strong and weak nuclear forces all give off energy when they lower potential. If gravity is a force, what type of output does gravity give off when it lowers potential? Does this output, connected to space-time contraction, fuel the expansion of universal space-time. The opposite of contracting space-time, is expanding space-time, with contraction of space-time being driven by a fundamental force that is lowering potential. The needed data would be to show that the number of stars and structure is increasing faster and faster in parallel to the acceleration of universal space-time. Are there more stars and structure now than at the beginning?

 

I

[sanctus]

HB, your first question you answered it yourself, there are LOCAL contractions, they do not affect the global expansion of space-time. If in galaxies or some cosmic dust stars are born, this hasn't an effect on wheter other galaxies far away from this point where a star is born are acelerating away...

[modest]

I don't follow, HydrogenBond. But, I should correct you in that spacetime doesn't expand and contract in the usual FLRW metric that people refer to in the metric expansion of space. Space expands and contracts. Space is different from spacetime and you really wouldn't want to say that spacetime is expanding in the case of the universe or contracting in the case of a collapsing star... just space.

 

~modest

 

EDIT: Then again, while I was posting Sanctus also said spacetime and definitely would know better than me, so... perhaps... :eek:

[sanctus]

You give me way too much credit Modest ;-), I think that you are right and I was wrong. The distance between 2 points increases in time...

[HydrogenBond]

The point I was making are when the EM, weak and strong nuclear forces lower potential energy is given off. If this energy quanta is absorbed by another similar force situation, the effect is the reversal of the force to higher potential. If a hydrogen atom moves to lowest energy state, energy is given off. This can cause another hydrogen atom to increase potential back to the previous state of the first hydrogen. It sort of looks like an anti-force effect (we won't define it that way).

 

If gravity is a force and gives off some type of energy; dark energy?, when it lowers potential, this energy will appear to have an anti-gravity effect, that increases the gravity potential elsewhere, like a hydrogen atom being kicked up in potential, by the output of another hydrogen lowering potential.

 

It is not obvious that gravity, when lowering potential, will give off anything. If it does not give off anything when lowering potential, it is not a force, exactly like the rest, which may be why it is hard to integrate. But maybe we are looking in the wrong place for an expected type of energy output. We may need to look at the predicted effect, which would be to reverse gravity elsewhere. Do we see that in the universe? yes.

 

Since the universe is expanding relative to galaxies, and the galaxies are lowering gravity potential, one would expect an antigravity looking effect, especially in the space between them, with all the galaxies showing anti-graivty expansion, between them.

 

What I suggested is seeing if the number of stars and forming bodies, which represent gravity lowering potential, is increasing over time. This may be hard to do, since as technology improves, we see more and more. Or is the formation of new stars occurring faster than the rate at which stars are being lost?

[modest]

It is not obvious that gravity, when lowering potential, will give off anything.

 

It's not obvious what you mean. If you mean that an object lowers in gravitational potential then the answer is that the potential is converted to kinetic energy. If, for example, an object falls into earth's gravity well it accelerates some 11 m/s.

 

If you mean, and I think you do, that the gravitational field is becoming more curved because a mass is collapsing then the answer would be that no gravitational energy is radiated away. It's proved in Beckham's theorem... no, wait... I'm thinking of the spice girl... Birkhoff's theorem! It's proved in Birkhoff's theorem. A collapsing spherically symmetric arrangement of mass radiates no gravitational energy (ie gravitational waves).

 

~modest

[HydrogenBond]

It's not obvious what you mean. If you mean that an object lowers in gravitational potential then the answer is that the potential is converted to kinetic energy. If, for example, an object falls into earth's gravity well it accelerates some 11 m/s.

 

The EM force between charges separated by a distance, will also accelerate and increase kinetic energy. But it will also give off energy on top of that. Gravity does the acceleration thing, (check), the kinetic energy thing (check), but where is the energy output like the EM, weak and strong nuclear forces?

 

In all those cases, the energy output can reverse the force in a neighboring system, with the effect "sort of looking like" the anti of that force; the energy output can cause an electron to be kicked up in a way that opposes the EM force. If gravity is a force like the rest, we should expect an anti effect. I am not saying this an anti-gravity any more than energy into an atom creates anti EM. But both look that way.

 

If we look at the universe and work under the assumption of an "anti" effect relative to gravity, and use all the matter in the universe as the source of this output, what would the universe do in the space between, where gravity is very low but the output of all the anti looking effect is higher in comparison? Say this anti output was reaching a galaxy, at the same time it is lowering gravity potential. The result should be two opposing things, with a combination of collapse and resistance to collapse (rotation).

 

Gravity, as relativity, is connected to space-time, with gravity contracting the space-time as more matter collects. The anti should then be the opposite and be connected to what appears to be expanding space-time, that will oppose contracting space time. At the surface of galaxies we get rotation due to balance of effects, but in the space between, where gravity is much less due to less matter, we get space-time expanding.

 

I understand this is not convention, but it seems to add up. When it comes to dark matter and dark energy, these are inferred from effect and not by collecting a sample of each in the lab. I don't have a sample either, but am inferring from the expected effects. Maybe dark energy is the output of gravity, since it creates the anti effect one would expect from the output of gravity. As more and more mass lowers gravity potential the amount of anti or dark energy should increase ,with the conservation of energy causing it to collect unless it can be converted to something else. If matter is no around in sufficient amounts to store the potential, space-time picks up the slack.

[coldcreation]

I don't follow, HydrogenBond. But, I should correct you in that spacetime doesn't expand and contract in the usual FLRW metric that people refer to in the metric expansion of space. Space expands and contracts. Space is different from spacetime and you really wouldn't want to say that spacetime is expanding in the case of the universe or contracting in the case of a collapsing star... just space.

 

~modest

 

EDIT: Then again, while I was posting Sanctus also said spacetime and definitely would know better than me, so... perhaps...

 

 

You give me way too much credit Modest ;-), I think that you are right and I was wrong. The distance between 2 points increases in time...

 

Actually, the expansion of space is not a three-dimensional phenomenon, but of 4-D. This is referred to as spacetime. To consider expansion solely in terms of space is inaccurate. But simultaneously, time itself doesn't expand, it dilates. So technically, it could be argued that only space expands, without the time component. I would be reticent of separating time from space with respect to expansion. The reason becomes clearer when the clocks are run backwards, toward the big bang. Both space and time (together) are undergoing contraction (I think ). As the universe becomes smaller, time approaches zero, or something like that. I need another glass of vino.

 

So strangely enough, it seems you and modest are both correct (or both wrong) depending on how terms are defined. Here's a nice little tutorial that says "The expansion of space is four-dimensional (3 spatial and one time dimension); this is often referred to as spacetime". Remote Sensing Tutorial Page A-8

 

 

 

CC

[HydrogenBond]

The model proposed uses the "theoretical" output from the lowering of gravitational potential or GR, to cause an output effect that is the opposite relative to space and time. We call this the expansion. In the current model, we still need potential to cause the acceleration expansion of the universe, which is attributed to dark stuff. I propose the lowering of gravity potential is the output source of this potential.

 

Let us start at time=0++. For the universe to expand, in this model it would require gravity begin clumping the matter almost immediately, generating the needed output. There is data that shows stars were around very early in the universe; in spite of rapid expansion. This make sense with cause=gravity and effect=expansion. The faster the expansion, the stronger gravity would need to be acting. If gravity was lagging, the expansion would also lag, so gravity is able to get back on pace. Nature makes it fail-safe.

 

Conceptually, during the initial inflation, gravity is reversing, so where is the initial output potential, if gravity is going the wrong way? One possible explanation is, the inflation is connected to the unified force, before gravity has differentiated. Once gravity differentiates, matter begins to clump, with the output potential having an anti-clump and expansion effect, taking care of expansion/differentiation into galaxies and stars but at the pace set by the gravity.

 

This model would have the universe continuing to expand as long as matter is lowering gravity potential, somewhere in the universe, with the expansion eventually no longer accelerating, as matter lowers output potential; static clumps. Then the static matter clumps, such as black holes, impact each other stronger with gravity (without the same level of accelerating anti-effect). As they attract, this new gravity output potential causes another anti-gravity looking effect. There is a collapsing "rotation" of the universe as the universe heads down the drain for another cycle.

[C1ay]

Looking at the big picture the question to me becomes is the Universe infinite or not? If not, it implies that the Universe is bounded and the question becomes what is it bounded by? BTW, if it is expanding then what is it expanding into? I know, more questions than answers but it is these questions that lead me to favor the idea that the size of the Universe is infinite.

[modest]

Actually, the expansion of space is not a three-dimensional phenomenon, but of 4-D. This is referred to as spacetime. To consider expansion solely in terms of space is inaccurate.

 

Yeah, I agree ;) Expansion certainly would be a 4D phenomenon. I wouldn't argue that time isn't involved, only that in a FRW metric, which is very good at modeling an expanding universe or a collapsing star, it is the spatial distance alone which increases or decreases.

 

But, to be honest, I'm not sure what it would look like or even what it would mean for spacetime distances to increase or decrease :Alien:

 

But simultaneously, time itself doesn't expand, it dilates. So technically, it could be argued that only space expands, without the time component.

 

:cheer:

 

I would be reticent of separating time from space with respect to expansion. The reason becomes clearer when the clocks are run backwards, toward the big bang. Both space and time (together) are undergoing contraction (I think :cheer:). As the universe becomes smaller, time approaches zero, or something like that. I need another glass of vino.

 

:evil:

 

Maybe a collapsing star would be the best point of reference because we can compare it to the outside universe. As the star collapses every point gets closer to every other point in a way that's modeled very well by the metric expansion of space (or, I guess, the reverse of that). But, also, as it collapses each point falls into a deeper gravity well so that time slows down a bit. But, that's like stretching time so that space would be collapsing and time would be expanding... hummm.... ;) I'm thoroughly confused :Alien:

 

~modest

[nevaeh.aaric]

The current, observable universe has been determined to have a width of 156 billion light years, with an error of less than 1%, by the latest deep-space telescope WMAP. At first, it might seem impossible that scientists are so sure of this astronomical measurement, but this figure has been narrowed by years of research and determined by several paths of inquiry. Also, the size of the universe is intimately dependent on its shape, age, acceleration, and total mass, so we are very confident in this figure. Remember that the size of the universe is not a constant value, nor is it the size of an object as we traditionally understand it. The size of the universe is actually the size of space itself, and as space expands, so does the space between planets, stars, and galaxies. At the beginning of the universe, the Big Bang created space and time as we know them. From that moment, space has been expanding, so we find its size by measuring how far light could have traveled since the Big Bang, along with how much space itself stretched. We can only possibly look or communicate up to the edge, or "horizon," of where light has traveled since the beginning of the universe. The size of the universe means the space in which we can interact with anything. We will never ever know what is "beyond" this boundary, because there is no way to know anything about it, so it's illogical to consider the realm "outside" of our universe, or to wonder what we are expanding "into.

[Boerseun]

Nevaeh, credit your sources! :steering:

 

You stole that quote word-for-word from wiseGEEK: clear answers for common questions. Quit it, now.

[ajtony]

Just thinking about size of the universe and the predictions achieved from the observations made from earth. In regards to the age of the universe put at approximately 13. something billion yrs. (please bear with me) It was Hubbles observations of the red shift as galaxies moved away from each other that started this journey. And lately with the advances in astronomy technology mated to advances in computers and software we have supposedly looked extremeley far back to the begining of the universe. The big bang is getting tantilizing close to being seen, (which is a misnomer to be actually able to witness the "start" since light didn't exist at this "time" in fact "the start" is in essence a misnomer since "time" also didn't exist either. But I digress.) My main porblem is pretty basic and I haven't had trraining in advance cosmotology so I could very well ignorant of facts. If at the "birth" of the big bang and proceeding along to the actual systhesis of time/matter and using this as a starting piont: for ease of computation lets just say that matter was traveling at 1/2 the speed of light or .5C. Then in this time frame the light would have outpaced the matter that it originally emanated from by .5 x 13.7billion light years. In other words the light of the Big Bang should be 6.85 billion years ahead of us. In point of fact light would have always been ahead of the matter that it emanated from. Since the first creation of stars and then galaxies and so on there has been serveral generations of both. The death of one generation birhting the next. The original matter that light first came from is no longer so it can no longer be producing "first light". I understand the analegy concept that the expanding universe is like a ballon and the space time is the "skin" and matter is embeded in this skin. This of course leaves a emptiness relative to the center of the universe. Unless new matter is constantly refershed at a constant escalated pace what is there to look back to? Could the increase in red shift on the galatic scale not only be a function of speed but also distance. Two galaxies with different red shifts could be going the same speed away but are at different distance from us. Is there a "substance" light has to travel thru in the universe that causes a lenghtening of the spectrum?

[modest]

Just thinking about size of the universe and the predictions achieved from the observations made from earth.

 

Hi Tony. Welcome to Hypography.

 

I'd first and foremost recommend Ned Wright's cosmology tutorial and also NASA's Big Bang tutorial.

 

If at the "birth" of the big bang and proceeding along to the actual systhesis of time/matter and using this as a starting piont: for ease of computation lets just say that matter was traveling at 1/2 the speed of light or .5C. Then in this time frame the light would have outpaced the matter that it originally emanated from by .5 x 13.7billion light years. In other words the light of the Big Bang should be 6.85 billion years ahead of us. In point of fact light would have always been ahead of the matter that it emanated from.

 

According to standard cosmology the earliest light we can see was was emitted when the universe was about 379,000 years old (roughly .003% of its current age). We currently see that light as the cosmic microwave background.

 

When that light was emitted there were not yet any galaxies. There was matter that would eventually clump together and form galaxies and eventually form earth and us. When the universe was 379,000 years old let's consider two spots of matter. There is the matter that would eventually become the Milky Way with us in it making our observations (let's call this the primordial us), and there is the matter that emitted the CMB light that we are currently observing (we'll call this the primordial emitter). It eventually became a very distant and fast moving galaxy.

 

So, more than 13.6 billion years ago the primordial emitter was 36 million light-years away from the primordial us. The space between the two was expanding faster than the speed of light which means that the primordial emitter shined light at the primordial us, but the light although aimed at the primordial us, was still moving away from us.

 

The light was, however, making progress. As time went on and the light crossed its local space it slowed relative to the primordial us. By about 12 billion years ago it was moving away from us at twice the speed of light and a little more than 9 billion years ago it crossed what's called the Hubble distance where the expansion speed is equal to the speed of light. At that point it started moving towards us.

 

9 billion years later we are just now seeing the light. When it was emitted the primordial emitter was only 36 million light-years from the primordial us, but the primordial emitter eventually became a galaxy that is now 46 billion light-years from us and currently expanding much, much faster than the speed of light from us.

 

I understand the analegy concept that the expanding universe is like a ballon and the space time is the "skin" and matter is embeded in this skin. This of course leaves a emptiness relative to the center of the universe.

 

I'm afraid that is a common misconception. The balloon analogy is meant to show in two dimensions what happens in our world in three dimensions. The balloon shows expansion of a surface and you should pretend that there is no inside to the balloon and no thickness to its material. The surface of the balloon should be two dimensional. The way distance behaves on the 2D surface of the balloon is how distance behaves in our 3D universe because of the metric expansion of space.

 

Unless new matter is constantly refershed at a constant escalated pace what is there to look back to?

 

Many people think of the big bang as matter exploding out of one place in space, but it's better to think of the universe itself expanding. The whole universe is full of matter today and looking back in time when the universe was scaled down, it was full of matter then too.

 

Could the increase in red shift on the galatic scale not only be a function of speed but also distance. Two galaxies with different red shifts could be going the same speed away but are at different distance from us. Is there a "substance" light has to travel thru in the universe that causes a lenghtening of the spectrum?

 

This would be called tired light and there is really no evidence for it, but a lot of evidence against it.

 

~modest