The Universe, who is fascinated by that?

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#1621090 1-Sep-2016 22:56

tdgeek:

joker97:

tdgeek:

joker97:

TwoSeven:
gzt:
TwoSeven: I am not sure how many people are familiar with the current version of einsteins field equation for general relativity, but the way I read it would be that for the big expansion (which some people call a bang) it implies that energy has a pressure which must push things outwards.

Not all forms of energy exist all of the time, and some forms of energy we guess is there by observing potential effects on things we can see. I am not sure I agree with the concep of dark matter, but dark energy is plausible although I am leaning to the idea of there being dark fields.

Also, time is relative to space, so I don't think there could have been a 'before the big bang' in the same way there is likely no after (since it is still happening).

New galaxy discovery: 99.99% dark matter.

Imo we will have an answer soon building on this discovery. 10-20 years..

I saw that article and don't really agree with it. Everything discovered these days is either dark matter or dark energy. Maybe if they build a better telescope they will figure out what it really is.

Umm ... no one has discovered any dark matter or any dark energy as far as I know. And you don't need a telescope to analyse dark matter and dark energy (assuming you've discovered it). You probably just need to step outside the ISS to do so.

So you didn't read it. Read it to learn how they decided what the total mass is, and with the low count of stars, that the remainder is dark matter, matter that would have the same effect as millions or billions of stars, but is not visible. You can't take this readings tethered to the ISS

If you had discovered dark matter and dark energy, you will know that it is what "space" is made of. How do you analyse "space"? Go outside and take a piece of it!

If dark energy is what space is made of, it might well be whats also in space, but you cannot see it. Whatever the article saw, or in this case, didn't see, has an energy affect of many many stars.

No the article saw dark matter.

It's like you see a bicycle drive like a tank. But you see a bicycle. So you hypothesize that there a tank around the bicycle but you can't see it. Alternatively, you never understood how objects move (ie the theory of gravity was wrong).

Dark energy is what is postulated to cause the expansion of space-time. (Remember, gravity is supposed to pull ... not push)

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#1621091 1-Sep-2016 22:58

Paul1977:

tdgeek:

Rikkitic:

That intuitive thinking is why people get confused. Imagine the balloon sunk down to a single point. There is no 'inside', only outside. that is the centre of the universe. Then the balloon expands. It is still the centre, but the centre is the whole balloon. There is no 'inside'. That is just a construct of our limited imaginations. As the balloon grows bigger, so does the Universe, but every point of it is still the centre. When you look across space, or backward in time, you are not looking at a different point on the balloon but at an earlier moment of the expansion.

If the balloon was down ti a single point where the point cannot be smaller, yes there is no inside. There, by default, there also cannot be an outside. And again by default there cannot be a centre. The Universe however is not a single point. It comprises hard matter, gases, and space. It started as a single point, expanded into countless atoms that make up countless volume of all types of matter, so everywhere in the universe cannot be the centre. Aside from deciding that anyone who doesn't agree has limited imagination, you are saying that Earth is the centre of the Universe, as is Alpha Centauri, as is a star in the Andromeda galaxy. When the ballon grows, the centre is mid diameter of a sphere. As that sphere expands, the centre remains the centre. Where it all began, aka Big Bang theory. The Universe would not have a centre if it was infinite, but it cannot be infinite as it is expanding. Time is not relevant, aside from the expansion being at an earlier stage

It's tricky stuff. For our universe to be expanding, it surely must be expanding within some larger construct. I guess that's where extra dimensions come in, and it is extremely difficult for us to conceptualize anything beyond the 4 dimension we experience (it's often difficult enough to think of time as a dimension).

With the balloon analogy you have to remember that a dimension has been removed to make it easier for us to understand the concept. The universe is represented by the surface of the balloon, not the 3D inflated balloon that we are looking at. So the question is not "where is the centre of the balloon?" but rather "where is the centre of the surface of the balloon?".

I personally don't like the balloon analogy though. It implies that the universe is finite, and that if you travel in one direction long enough you will end up back where you started. I don't know that this was the intention though?

It's not expanding within a larger construct. The whole construct is expanding. Space-time is expanding. Other dimensions are not directly involved, only the 4.

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#1621092 1-Sep-2016 23:00

joker97:

tdgeek:

joker97:

tdgeek:

Rikkitic:

I am in no way knowledgeable about this and the maths are way over my head, but from what I think I understand, the big bang was not an explosion at all, just an expansion. Space itself started small and then grew bigger. It is still growing bigger. When the big bang happened, all of space was confined to a single point. That was the centre of the Universe. As space expanded, so did the centre. In other words, every point in space is the centre of the Universe so every direction you look will be back to the beginning. The mistake is in visualising it as an explosion that occurred in a bigger space. The centre of the Universe started out as a singular point which was as big as all of existence and since then everything has been expanding so the centre is still as big as the entire Universe and it always will be. Wherever you are, you are at the centre, just as every other point is. Think again of the famous balloon example. The centre is not in the middle of the balloon, but on the surface. As the balloon expands, all the other points get further away, but each is the centre to all the rest.

As I recall it was a sudden release of everything. How sudden and fast that was depends what people decide an explosion is. Not silica, particles, etc, but energy. Atoms did not exist then, IIRC

If the big bang happened at a point, and the universe expanded, the location of the big bang surely has to be the centre. The balloon was IMO to show how expansion illustrates how observable matter such as stars, galaxies move away from each other, relative to each other. But the universe isn't just he balloons surface, its three dimensional. IMO the centre of the universe is the centre of the balloon, where the expansion shows that matter in-between us and the centre moves apart, as do matter on the outer of us, or matter that is nearer to a tangent to us, sideways if you will.

Umm AFAIK the smart guys believe the universe is infinite.

if d=∞ then r=∞ then there is no centre

Agree, as I said in my post just now, an infinite universe cannot have centre. So, who says it is expanding> If it is expanding, its larger now than what it was 10 seconds ago, thats not infinite.

It could be that the universe is in fact infinite, and what populates it is finite, and expanding. In that case there is no centre of the universe, just a centre of the matter occupied volume that is expanding. The Universe is thus not everything. It is just the infinite volume of space, of which a tiny portion is occupied, percentage wise, and past the expanding edge, there is universe, but zero matter in it. yet

Pretty sure it's infinite.

Google gives the answer that its unknown as we cannot measure it past the 93 billion light years across we know it is, in what we observe.

Brings me back to the big bang. Starts at a dot and expands. If the Universe is infinite, the big bang cannot have created the universe, expanded t, and then left it infinite. Space must have always been here, infinite. The content of space, created by the big bang is what is expanding, and is finite. I like my theory. I see space as not a dimension.

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#1621094 1-Sep-2016 23:07

tdgeek:

Google gives the answer that its unknown as we cannot measure it past the 93 billion light years across we know it is, in what we observe.

Brings me back to the big bang. Starts at a dot and expands. If the Universe is infinite, the big bang cannot have created the universe, expanded t, and then left it infinite. Space must have always been here, infinite. The content of space, created by the big bang is what is expanding, and is finite. I like my theory. I see space as not a dimension.

That is beyond me so I say I don't know. I thought they thought it was infinite. Maybe the smart guys changed their minds.

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#1621095 1-Sep-2016 23:08

joker97:
Paul1977:

tdgeek:

Rikkitic:

That intuitive thinking is why people get confused. Imagine the balloon sunk down to a single point. There is no 'inside', only outside. that is the centre of the universe. Then the balloon expands. It is still the centre, but the centre is the whole balloon. There is no 'inside'. That is just a construct of our limited imaginations. As the balloon grows bigger, so does the Universe, but every point of it is still the centre. When you look across space, or backward in time, you are not looking at a different point on the balloon but at an earlier moment of the expansion.

If the balloon was down ti a single point where the point cannot be smaller, yes there is no inside. There, by default, there also cannot be an outside. And again by default there cannot be a centre. The Universe however is not a single point. It comprises hard matter, gases, and space. It started as a single point, expanded into countless atoms that make up countless volume of all types of matter, so everywhere in the universe cannot be the centre. Aside from deciding that anyone who doesn't agree has limited imagination, you are saying that Earth is the centre of the Universe, as is Alpha Centauri, as is a star in the Andromeda galaxy. When the ballon grows, the centre is mid diameter of a sphere. As that sphere expands, the centre remains the centre. Where it all began, aka Big Bang theory. The Universe would not have a centre if it was infinite, but it cannot be infinite as it is expanding. Time is not relevant, aside from the expansion being at an earlier stage

It's tricky stuff. For our universe to be expanding, it surely must be expanding within some larger construct. I guess that's where extra dimensions come in, and it is extremely difficult for us to conceptualize anything beyond the 4 dimension we experience (it's often difficult enough to think of time as a dimension).

With the balloon analogy you have to remember that a dimension has been removed to make it easier for us to understand the concept. The universe is represented by the surface of the balloon, not the 3D inflated balloon that we are looking at. So the question is not "where is the centre of the balloon?" but rather "where is the centre of the surface of the balloon?".

I personally don't like the balloon analogy though. It implies that the universe is finite, and that if you travel in one direction long enough you will end up back where you started. I don't know that this was the intention though?

It's not expanding within a larger construct. The whole construct is expanding. Space-time is expanding. Other dimensions are not directly involved, only the 4.

It might be expanding within a larger construct, some theories postulate an additional 7 dimensions.

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#1621096 1-Sep-2016 23:10

Paul1977:

It's tricky stuff. For our universe to be expanding, it surely must be expanding within some larger construct. I guess that's where extra dimensions come in, and it is extremely difficult for us to conceptualize anything beyond the 4 dimension we experience (it's often difficult enough to think of time as a dimension).

With the balloon analogy you have to remember that a dimension has been removed to make it easier for us to understand the concept. The universe is represented by the surface of the balloon, not the 3D inflated balloon that we are looking at. So the question is not "where is the centre of the balloon?" but rather "where is the centre of the surface of the balloon?".

I personally don't like the balloon analogy though. It implies that the universe is finite, and that if you travel in one direction long enough you will end up back where you started. I don't know that this was the intention though?

The universe is expanding, that seems the common theory. If from the big bang, that means it is expanding in all directions, spherical. Finite.

I saw the ballon example as not of the universe, but how galaxies etc move away from themselves and everything else due to expansion. The surface of the ballon is convenient to show the outer rim galaxies, but the content of the universe exists inside the sphere.

Is the expansion equal velocity? I think it is, with minor variations, cannot recall. If so, then the centre outwards, at that speed for 13.8 billions years should be empty?

Last point. If the Universe is spherical and expanding out from the big bang, it would be the same as the Earth, travel in one direction (well, its not really) and you end up home again. Except the expansion dispels that theory although the principle applies.

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#1621098 1-Sep-2016 23:13

joker97:

No the article saw dark matter.

It's like you see a bicycle drive like a tank. But you see a bicycle. So you hypothesize that there a tank around the bicycle but you can't see it. Alternatively, you never understood how objects move (ie the theory of gravity was wrong).

Dark energy is what is postulated to cause the expansion of space-time. (Remember, gravity is supposed to pull ... not push)

You said earlier that no one has discovered dark matter. Now you say the article saw dark matter. As in discovered. My point exactly.

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#1621100 1-Sep-2016 23:15

joker97:

It's not expanding within a larger construct. The whole construct is expanding. Space-time is expanding. Other dimensions are not directly involved, only the 4.

So, the universe is finite, glad we got that settled. I agree that the universe is the whole construct, so if its expanding it cannot by definition be infinite

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#1621101 1-Sep-2016 23:17

joker97:

tdgeek:

Google gives the answer that its unknown as we cannot measure it past the 93 billion light years across we know it is, in what we observe.

Brings me back to the big bang. Starts at a dot and expands. If the Universe is infinite, the big bang cannot have created the universe, expanded t, and then left it infinite. Space must have always been here, infinite. The content of space, created by the big bang is what is expanding, and is finite. I like my theory. I see space as not a dimension.

That is beyond me so I say I don't know. I thought they thought it was infinite. Maybe the smart guys changed their minds.

No one knows, basically as we cannot see past 47.5 billion year radius so there i no way to know. Unless they worked out how can everything be expanding and infinite, which is what I can't see.

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#1621102 1-Sep-2016 23:24

Paul1977:

It might be expanding within a larger construct, some theories postulate an additional 7 dimensions.

Its crazy stuff. If the universe was infinite, and even though the atom combinations to make an identical me would be horrendous, there would be another me, as there is no limit to the combinations of atoms that can be made. Then factor in everything I have done, that must be there as there is no limit. Multi verses are worse, they allow for everything in my life I could have done, if I took every possible choice available. Anything is possible in an infinite universe. While its all theory, its mathematics, but still crazy.

I'd prefer to relax watching how to terraform Mars, doco is on CuriosityStream!

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#1621155 2-Sep-2016 08:03

Paul1977:
joker97:

Paul1977:

tdgeek:

Rikkitic:

That intuitive thinking is why people get confused. Imagine the balloon sunk down to a single point. There is no 'inside', only outside. that is the centre of the universe. Then the balloon expands. It is still the centre, but the centre is the whole balloon. There is no 'inside'. That is just a construct of our limited imaginations. As the balloon grows bigger, so does the Universe, but every point of it is still the centre. When you look across space, or backward in time, you are not looking at a different point on the balloon but at an earlier moment of the expansion.

If the balloon was down ti a single point where the point cannot be smaller, yes there is no inside. There, by default, there also cannot be an outside. And again by default there cannot be a centre. The Universe however is not a single point. It comprises hard matter, gases, and space. It started as a single point, expanded into countless atoms that make up countless volume of all types of matter, so everywhere in the universe cannot be the centre. Aside from deciding that anyone who doesn't agree has limited imagination, you are saying that Earth is the centre of the Universe, as is Alpha Centauri, as is a star in the Andromeda galaxy. When the ballon grows, the centre is mid diameter of a sphere. As that sphere expands, the centre remains the centre. Where it all began, aka Big Bang theory. The Universe would not have a centre if it was infinite, but it cannot be infinite as it is expanding. Time is not relevant, aside from the expansion being at an earlier stage

It's tricky stuff. For our universe to be expanding, it surely must be expanding within some larger construct. I guess that's where extra dimensions come in, and it is extremely difficult for us to conceptualize anything beyond the 4 dimension we experience (it's often difficult enough to think of time as a dimension).

With the balloon analogy you have to remember that a dimension has been removed to make it easier for us to understand the concept. The universe is represented by the surface of the balloon, not the 3D inflated balloon that we are looking at. So the question is not "where is the centre of the balloon?" but rather "where is the centre of the surface of the balloon?".

I personally don't like the balloon analogy though. It implies that the universe is finite, and that if you travel in one direction long enough you will end up back where you started. I don't know that this was the intention though?

It's not expanding within a larger construct. The whole construct is expanding. Space-time is expanding. Other dimensions are not directly involved, only the 4.

It might be expanding within a larger construct, some theories postulate an additional 7 dimensions.

Those dimensions are needed to explain the existence of matter. You see, no science can show how matter can exist at the moment.

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#1621156 2-Sep-2016 08:17

tdgeek:

joker97:

No the article saw dark matter.

It's like you see a bicycle drive like a tank. But you see a bicycle. So you hypothesize that there a tank around the bicycle but you can't see it. Alternatively, you never understood how objects move (ie the theory of gravity was wrong).

Dark energy is what is postulated to cause the expansion of space-time. (Remember, gravity is supposed to pull ... not push)

You said earlier that no one has discovered dark matter. Now you say the article saw dark matter. As in discovered. My point exactly.

Blimey! No one has discovered dark matter.

You said the article saw dark energy. I am saying you are mistaken, the concept they saw was Not dark energy, but dark matter.

tdgeek:

joker97:

tdgeek:

joker97:

TwoSeven:
gzt:
TwoSeven: I am not sure how many people are familiar with the current version of einsteins field equation for general relativity, but the way I read it would be that for the big expansion (which some people call a bang) it implies that energy has a pressure which must push things outwards.

Not all forms of energy exist all of the time, and some forms of energy we guess is there by observing potential effects on things we can see. I am not sure I agree with the concep of dark matter, but dark energy is plausible although I am leaning to the idea of there being dark fields.

Also, time is relative to space, so I don't think there could have been a 'before the big bang' in the same way there is likely no after (since it is still happening).

New galaxy discovery: 99.99% dark matter.

Imo we will have an answer soon building on this discovery. 10-20 years..

I saw that article and don't really agree with it. Everything discovered these days is either dark matter or dark energy. Maybe if they build a better telescope they will figure out what it really is.

Umm ... no one has discovered any dark matter or any dark energy as far as I know. And you don't need a telescope to analyse dark matter and dark energy (assuming you've discovered it). You probably just need to step outside the ISS to do so.

So you didn't read it. Read it to learn how they decided what the total mass is, and with the low count of stars, that the remainder is dark matter, matter that would have the same effect as millions or billions of stars, but is not visible. You can't take this readings tethered to the ISS

If you had discovered dark matter and dark energy, you will know that it is what "space" is made of. How do you analyse "space"? Go outside and take a piece of it!

If dark energy is what space is made of, it might well be whats also in space, but you cannot see it. Whatever the article saw, or in this case, didn't see, has an energy affect of many many stars.

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#1621157 2-Sep-2016 08:17

tdgeek:

joker97:

It's not expanding within a larger construct. The whole construct is expanding. Space-time is expanding. Other dimensions are not directly involved, only the 4.

So, the universe is finite, glad we got that settled. I agree that the universe is the whole construct, so if its expanding it cannot by definition be infinite

You said it's not known.

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#1621161 2-Sep-2016 08:36

joker97:

tdgeek:

joker97:

It's not expanding within a larger construct. The whole construct is expanding. Space-time is expanding. Other dimensions are not directly involved, only the 4.

So, the universe is finite, glad we got that settled. I agree that the universe is the whole construct, so if its expanding it cannot by definition be infinite

You said it's not known.

Correct. You said its infinite, yet you say its expanding, which means it cannot be infinite. I was being mildy sarcy!

My belief is that space is space, its always existed. In fact you can't talk of space existing, as the content is what exists. Space is seen as something that can be made, i dont believe that. I'd also not call space a noun, a thing. What is a thing is things

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#1621163 2-Sep-2016 08:38

tdgeek:

joker97:

tdgeek:

joker97:

It's not expanding within a larger construct. The whole construct is expanding. Space-time is expanding. Other dimensions are not directly involved, only the 4.

So, the universe is finite, glad we got that settled. I agree that the universe is the whole construct, so if its expanding it cannot by definition be infinite

You said it's not known.

Correct. You said its infinite, yet you say its expanding, which means it cannot be infinite. I was being mildy sarcy!

My belief is that space is space, its always existed. In fact you can't talk of space existing, as the content is what exists. Space is seen as something that can be made, i dont believe that. I'd also not call space a noun, a thing. What is a thing is things

It doesn't matter what I think or what you think, but that the fact that Hawking can't explain it.

In my statements I always try to state the current most commonly accepted standings. I thought the current thought was it was infinite, but maybe not. You can do all sorts of mathematical functions on infinity. I did that in Uni but I can't remember any of them now!

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