Are We Living Inside A Blackhole?

[STR]

In no way does dark matter contradict relativity. Einstein never said light interacts with everything.

Dark energy is certainly not something Einsteinian, because he believed in a static, unchanging universe, yet it slots in fairly nicely with the rest Relativity.

Nobody is quite sure what is altering the Pioneer probes, so until there's more information you can't say what's going on. It may well be due to mis-calibration or malfunction, though unlikely.

 

[keekwai]

If it's expanding .. away from a "central" point (which it is) .. then it has a center.

It's not really expanding for a central point. It's expanding in all directions.

So .. you don't think the location of the "Big Bang" is the centre of the Universe then?

Maybe there were multiple "Big Bangs" in several locations?

??????

 

[STR]

Like I said, the epicenter of the big bang is not going to be any different that any other spot in the universe. No matter where you are, things appear to be racing away from you. As long as you're within the universe, you appear to be the center of it, since ALL space is expanding in ALL directions.

Let's say we're close enough to the "center" to see what's there (we may be), and Galaxy XYZ123 in Pisces is the only galaxy smack in the middle. Despite that fact, XYZ123 looks from our direction to be flying away from us in the exact same way as Galaxy ABC987 in Ursa Minor, which is not in the middle. We cannot tell because it's all relative.

The only way to tell what the center of the universe would be if you could somehow observe the universe from outside of it. Think taking Google Earth, and zooming out until you're outside of universe. Then, and only then, would you be able to tell that XYZ123 is the only galaxy not moving.

But that's impossible. You're in the universe, you're never leaving the universe, and there may be no "existence" outside of the universe. So the epicenter of the big bang is irrelevant to you, me, and everyone else in the universe.

 

[keekwai]

As long as you're within the universe, you appear to be the center of it, since ALL space is expanding in ALL directions.

Aren't you describing a hyperspherical universe there? I could say I find that hard to believe .. but then again .. anything is possible at the moment.

 

[Robert Maxwell]

As long as you're within the universe, you appear to be the center of it, since ALL space is expanding in ALL directions.

Aren't you describing a hyperspherical universe there? I could say I find that hard to believe .. but then again .. anything is possible at the moment.

I do find the hypersphere concept to be an elegant "solution," but even if we have an endless, open universe, there doesn't have to be a center. Everything is just moving away from everything else at high speed. There doesn't have to be a "center."

 

[JarodRussell]

It could be a whole bunch of stuff, but most observations point to exotic particles that don't interact with photons (so we can't see it), probably don't have a nuclear reaction, and only appear to interact with normal matter via gravity. So it only interacts via 1 of the 4 forces of the universe, making it really hard to figure out what it is.

I'd rather say that the formulas describing that 1 force have flaws.

I read some articles about the origin of Dark Matter again, and it's the result of an incredible amount of "guess work" and average values, and the holes showing up are filled with "well, it's Dark Matter then". That's almost embarrassing.

 

[keekwai]

A Hypersherical Universe couldn't have a centre. It just goes on forever in all directions .. eternity. That's my problem with it. It's hard to imagine eternity.

 

[Robert Maxwell]

A Hypersherical Universe couldn't have a centre. It just goes on forever in all directions .. eternity. That's my problem with it. It's hard to imagine eternity.

Here's where I bring out a popular analogy.

A hyperspherical universe can be thought of as one in which, when traveling in a straight line through three dimensions, you are traveling along the surface of a sphere in a fourth dimension--you just aren't directly aware of it.

So, for the analogy: say you have an ant walking on an orange. From the ant's limited perspective, he is walking on what appears to be a two-dimensional plane. But if he sets off in one direction and keeps going, he will eventually wind up back where he started, even though he never noticed a transition going from one side of the orange to the other.

The universe is big enough that the same thing could happen. You can start from one central point (Earth) and go in one direction. Keep going and you'll wind up in unfamiliar territory. Eventually, you will find yourself on the other "side" of the universe from where you started, but there will be no obvious transition. You just might notice as you approach Earth that the area looks familiar again.

No one is certain of the exact structure of the universe. The hypersphere is just one of the more elegant solutions that accommodates an ever-expanding universe that has no center and no outer boundary.

 

[keekwai]

Maybe the Universe is a "Mobius Strip"

 

[JarodRussell]

A Hypersherical Universe couldn't have a centre. It just goes on forever in all directions .. eternity. That's my problem with it. It's hard to imagine eternity.

Here's where I bring out a popular analogy.

A hyperspherical universe can be thought of as one in which, when traveling in a straight line through three dimensions, you are traveling along the surface of a sphere in a fourth dimension--you just aren't directly aware of it.

So, for the analogy: say you have an ant walking on an orange. From the ant's limited perspective, he is walking on what appears to be a two-dimensional plane. But if he sets off in one direction and keeps going, he will eventually wind up back where he started, even though he never noticed a transition going from one side of the orange to the other.

The universe is big enough that the same thing could happen. You can start from one central point (Earth) and go in one direction. Keep going and you'll wind up in unfamiliar territory. Eventually, you will find yourself on the other "side" of the universe from where you started, but there will be no obvious transition. You just might notice as you approach Earth that the area looks familiar again.

No one is certain of the exact structure of the universe. The hypersphere is just one of the more elegant solutions that accommodates an ever-expanding universe that has no center and no outer boundary.

I dunno, wouldn't that enable time travel into the past? If you can arrive where you started, in the 4th dimension?

 

[Robert Maxwell]

A Hypersherical Universe couldn't have a centre. It just goes on forever in all directions .. eternity. That's my problem with it. It's hard to imagine eternity.

Here's where I bring out a popular analogy.

A hyperspherical universe can be thought of as one in which, when traveling in a straight line through three dimensions, you are traveling along the surface of a sphere in a fourth dimension--you just aren't directly aware of it.

So, for the analogy: say you have an ant walking on an orange. From the ant's limited perspective, he is walking on what appears to be a two-dimensional plane. But if he sets off in one direction and keeps going, he will eventually wind up back where he started, even though he never noticed a transition going from one side of the orange to the other.

The universe is big enough that the same thing could happen. You can start from one central point (Earth) and go in one direction. Keep going and you'll wind up in unfamiliar territory. Eventually, you will find yourself on the other "side" of the universe from where you started, but there will be no obvious transition. You just might notice as you approach Earth that the area looks familiar again.

No one is certain of the exact structure of the universe. The hypersphere is just one of the more elegant solutions that accommodates an ever-expanding universe that has no center and no outer boundary.

I dunno, wouldn't that enable time travel into the past? If you can arrive where you started, in the 4th dimension?

No, why would it? You'd always be moving forward in time.

ETA: I just realized you're confusing a fourth spatial dimension with a temporal "fourth dimension." They aren't the same thing. A hypersphere does not imply time travel, it just means our universe consists of four spatial dimensions instead of just the three we experience (plus a temporal dimension.)

 

[keekwai]

It was all so much simpler when the Earth was flat!

 

[STR]

I'd rather say that the formulas describing that 1 force have flaws.

While gravity on the quantum level is almost an utter mystery, gravity on the macro scale is pretty well understood. Newton nailed it exactly for everything under a substantial fraction of c. Einstein filled in the rest of the blanks. Both of actual experimental data backing them up. Einstein predicted such things as gravitational lenses, which do exist with the exact properties described.

If you alter gravity, you mess up a lot of other things which you then have to correct for. It's been studied before, my personal favorite being that gravity starts to noticeably deviate from Newtonian norm at extremely long distances. I haven't heard much about that theory in a few years. I might have to look into it again. This theory, and all other alternatives, suffer from being less accurate or vastly more complex than even Relativity.

 

[Lindley]

So .. you don't think the location of the "Big Bang" is the centre of the Universe then?

In a sense, everywhere is the "location of the big bang".

Think of it this way. Choose an arbitrary point in space. This point is receding from Earth, and more specifically from the location where you are now sitting, because the space between the points is expanding.

However, the reverse of this implies that said point was, in the past, much closer to the point where you are sitting. In fact, the further back in time you go, the closer those two points are to each other. You can find a time where they are arbitrarily close, in fact (at least mathematically---I don't claim to know about Plank-scale stuff).

Now, let's assume for the moment that the universe has a "center" in some sense. We can choose this center to be the point in question; so, at some point in the past, the location in space where you are currently sitting was arbitrarily close to the center of the universe. Then, effectively, that point where you are sitting was the center of the universe at the time of the Big Bang.

 

[JarodRussell]

While gravity on the quantum level is almost an utter mystery, gravity on the macro scale is pretty well understood. Newton nailed it exactly for everything under a substantial fraction of c. Einstein filled in the rest of the blanks. Both of actual experimental data backing them up.

And plenty of observations conflicting with them.

 

[ProtoAvatar]

In no way does dark matter contradict relativity. Einstein never said light interacts with everything.

Dark energy is certainly not something Einsteinian, because he believed in a static, unchanging universe, yet it slots in fairly nicely with the rest Relativity.

Nobody is quite sure what is altering the Pioneer probes, so until there's more information you can't say what's going on. It may well be due to mis-calibration or malfunction, though unlikely.

STR,
The fact that the galaxies stay in one piece DOES contradict general relativity.
Bark matter is just a bandage over this problem - the ghost that adds the needed mass for relativity to apply and calculate a gravity field of the observed strength.

The same with dark energy - the fact that the universe's expansion accelerates contradicts general relativity and the 'hand-waving' of this problem away was called dark energy.

'Dark matter' is, at this point, hypothetical - a speculation to explain the gravity field of galaxies being too strong.
And no one managed to come up with a consistent theory regarding 'dark energy', so far.


PS - I'm talking about what generaal relativity says, not what Einstein beleived - I don't really care about that: you see, that's irrelevant.

 

[JarodRussell]

Sometimes I get the feeling that theoretical physics, especially where Dark Matter and Dark Energy is involved, are a bit like this:

 

[STR]

STR,
The fact that the galaxies stay in one piece DOES contradict general relativity.
Bark matter is just a bandage over this problem

Bark matter (sic), has proven to be a far cleaner solution to the problem than doing anything else. It is, at its core, saying "maybe there's matter out there we can't easily detect," rather than "maybe we don't understand the forces of the universe enough." The standard model, as abridged and patched has stood up far better than the theories which preceded it and those that compete with it.

While I'm certainly open to going back to basics and doing it all over (many others have) the solutions that come from these reexaminations are less accurate than SM and more complicated. Not saying the answer isn't out there, just that as bad as Newton+Relativity+QM+Big Bang+DM+DE appears to be, every thing else is far worse off.

 

[keekwai]

Maybe there is something outside the bounds of the universe .. attracting or pulling the edges towards it .. thus .. the increasing speed of the expansion. Who knows?

 

[ProtoAvatar]

STR,
STR,
The fact that the galaxies stay in one piece DOES contradict general relativity.
Bark matter is just a bandage over this problem - the ghost that adds the needed mass for relativity to apply and calculate a gravity field of the observed strength.

The same with dark energy - the fact that the universe's expansion accelerates contradicts general relativity and the 'hand-waving' of this problem away was called dark energy.

'Dark matter' is, at this point, hypothetical - a speculation to explain the gravity field of galaxies being too strong.
And no one managed to come up with a consistent theory regarding 'dark energy', so far.


PS - I'm talking about what generaal relativity says, not what Einstein beleived - I don't really care about that: you see, that's irrelevant.

Bark matter (sic), has proven to be a far cleaner solution to the problem than doing anything else. It is, at its core, saying "maybe there's matter out there we can't easily detect," rather than "maybe we don't understand the forces of the universe enough." The standard model, as abridged and patched has stood up far better than the theories which preceded it and those that compete with it.

While I'm certainly open to going back to basics and doing it all over (many others have) the solutions that come from these reexaminations are less accurate than SM and more complicated. Not saying the answer isn't out there, just that as bad as Newton+Relativity+QM+Big Bang+DM+DE appears to be, every thing else is far worse off.

"Bark matter (sic), has proven to be a far cleaner solution to the problem than doing anything else."
And string theory is supposed to be a clean solution for unifying the forces of nature.
And they have something else in common - both are unproven speculations.

Plus - general relativity is under attack from dark enery and pioneer anomaly, too - and there is not even an unproven conjecture as to what causes them.

Rather than attributing all these experimental deviations to different causes, I thing they are all due to a factor we failed to take into account in relativistic calculations - of course, this is just speculation on my part.

PS - We are talking about relativity, which, so far, could not be incorporated into the standard model. Special relativity is in trouble, not the (largely empirically derived) standard model;

"Newton+Relativity+QM+Big Bang+DM+DE"
General relativity contradicted Newton on quite a few important points;
DM+DE - why are you even including them in the sphere of what we can explain?