Unknown "Structures" Tugging at Universe, Study Says

[The Grim Squeaker]

If the ship just falls off the edge of the world and keeps falling forever, couldn't the sailors just live normal lives inside the hull until they die?

Depends if they hit the Turtle's tail in the way down

[Havok]

If the ship just falls off the edge of the world and keeps falling forever, couldn't the sailors just live normal lives inside the hull until they die?

Normal? NONSENSE!! They would run out of booze.

[Samuel]

If the ship just falls off the edge of the world and keeps falling forever, couldn't the sailors just live normal lives inside the hull until they die?

Until the scurvy kills them. Build a big enough ship with its own growing room though and you are set...

[Ford Prefect]

If the ship just falls off the edge of the world and keeps falling forever, couldn't the sailors just live normal lives inside the hull until they die?

Setting aside the jokes, I don't think they could. I'm really sketchy on this, but they might well be in freefall, which means they'd be in a microgravity environment. They could probably adapt to this in terms of movement, and it does mean the orientation of the ship would be irrelevant, but there are other issues regarding microgravity environments. None of which would be faster than starving to death, but this getting so enormously off-topic.

While I think this whole concept is fascinating, at the same time it is also intimidating. Whole galactic superclusters being tugged along by structures beyond the 'horizon' of the universe we can observe? Scary. All the more reason to find out what's causing it ... or to use it in bad science fiction.

[Count Chocula]

Yeah Ford, it's a mind-bender. From what I recall of astronomy, the galaxies that we have observed, including our own, seem to have predictable and consistent orbital motions. If our entire observable universe is being dragged to some point "beyond the horizon," presumably by gravitational attraction, and we aren't seeing gross distortions of galaxies or superclusters, it makes our 10 billion+ light-year observable universe look like it's the size of one star in the night sky. Creepy, and a bit humbling.

[starslayer]

Setting aside the jokes, I don't think they could. I'm really sketchy on this, but they might well be in freefall, which means they'd be in a microgravity environment. They could probably adapt to this in terms of movement, and it does mean the orientation of the ship would be irrelevant, but there are other issues regarding microgravity environments. None of which would be faster than starving to death, but this getting so enormously off-topic.

Continuing the hijack, no, starvation would not be a problem, assuming infinite quantities of food. The body can swallow, digest, and metabolise food and fluids even upside down, because we move things along by peristalsis (muscle contractions). After all, astronauts and cosmonauts aboard the ISS aren't in the throes of starvation, and one cosmonaut was on Mir for over a year.

As for the dark flows, there's no way this is gravitational if real, because gravitational interactions travel at c in both GR and any proposed theory of quantum gravity. Gravity is bound by the same rules as light with regard to light cones and absolute elsewheres.

[Adrian Laguna]

Relating to dark matter, I've read that if you add a fudge factor to gravity that changes how it affects objects at truly large scales then you can explain and predict the observed motions of the universe without needed to postulate the existence of dark matter. I think that hypothesis (theory?) hasn't gained much traction because dark matter is more testable.

If the ship just falls off the edge of the world and keeps falling forever, couldn't the sailors just live normal lives inside the hull until they die?

"Normal" is not the word I would use, they would be living in free-fall, with no gravity to hold them down. They would probably live until the fresh water supplies ran out. An altogether unpleasant experience.

[Adrian Laguna]

they would be living in free-fall, with no gravity to hold them down

This is incorrect. Living in free-fall means there is no object to hold you up.

[starslayer]

Relating to dark matter, I've read that if you add a fudge factor to gravity that changes how it affects objects at truly large scales then you can explain and predict the observed motions of the universe without needed to postulate the existence of dark matter. I think that hypothesis (theory?) hasn't gained much traction because dark matter is more testable.

It's a hypothesis (I've never heard this one before; where'd you read it?). The reason it hasn't gained much traction is that GR as is has passed every test posed to it, and there is no indication that it needs to be modified on extremely large scales (though I admit I'm don't know the ins and outs of GR). Thus, dark matter makes more sense than adding a fudge factor to GR which has no justification whatsoever that we can tell. So in a way, you're right, dark matter is more easily tested for. In fact, the LHC is hoped to provide the first evidence as to what particles might constitute dark matter.

[NoXion]

Whatever happened to the idea that dark matter was simply white dwarves, neutron stars, brown dwarves, very dim stars etc?

[starslayer]

Whatever happened to the idea that dark matter was simply white dwarves, neutron stars, brown dwarves, very dim stars etc?

MACHOs may very well be part of dark matter, but the idea that they are the primary component of such has fallen by the wayside; I'm not sure why. Now it is presumed to mainly be a sea of WIMPs (Weakly Interacting Massive Particles), which some believe the LHC may be able to create (there would be missing mass and momentum carried away by the particle).

[Samuel]

Whatever happened to the idea that dark matter was simply white dwarves, neutron stars, brown dwarves, very dim stars etc?

MACHOs may very well be part of dark matter, but the idea that they are the primary component of such has fallen by the wayside; I'm not sure why. Now it is presumed to mainly be a sea of WIMPs (Weakly Interacting Massive Particles), which some believe the LHC may be able to create (there would be missing mass and momentum carried away by the particle).

There isn't enough MACHOs. They can test for them by seeing how they intredict the light coming from another galaxy- I think they used one of our sattilite galaxies or Andromeda.

There weren't enough stuff out there to account for the mass. You see, our galaxy has a large amount of mass that we simply can't see. The speed should fall of at the rim, but it doesn't which means there is more to our galaxy beyond the rim.

Since there isn't enough of the MACHOs, it has to be something else.

[cosmicalstorm]

I remember a quote from somewhere stating roughly that "Our observable universe might in relation to the entire universe be what a penny is in relation to the total area of the planet earth"

Was that only pulled out of somebodys ass or are there actual estimations for the size of the entire universe?

[LMSx]

I find it entirely fascinating/interesting/humbling/empowering knowing all these theories about the universe stems from the observations of a few beings on a single solitary planet having been given for just a couple lifetimes a reasonable framework for describing it all.

On the other hand we *are* a part of the universe, no reason we can't plumb its depths.

[starslayer]

There isn't enough MACHOs. They can test for them by seeing how they intredict the light coming from another galaxy- I think they used one of our sattilite galaxies or Andromeda.

There weren't enough stuff out there to account for the mass. You see, our galaxy has a large amount of mass that we simply can't see. The speed should fall of at the rim, but it doesn't which means there is more to our galaxy beyond the rim.

Since there isn't enough of the MACHOs, it has to be something else.

That makes sense. Not to be an ass, but I already know the stuff in your second paragraph (see my previous posts). And it's "aren't" and "wasn't."

Was that only pulled out of somebodys ass or are there actual estimations for the size of the entire universe?

That may have very well been pulled out of somebody's ass, but there have been estimations of the true size of the universe; I don't know what they are though.

[Ford Prefect]

Continuing the hijack, no, starvation would not be a problem, assuming infinite quantities of food.

I was not assuming infinite quantities of food.

As for the dark flows, there's no way this is gravitational if real, because gravitational interactions travel at c in both GR and any proposed theory of quantum gravity. Gravity is bound by the same rules as light with regard to light cones and absolute elsewheres.

This just piques my curiousity even more. If it is real, then who knows what sort of amazing implications this would have on our understanding of the universe. This intruiges me in the way only extraordinarily vague scientific theories can.

[Darth Raptor]

The most obvious implication is that our universe is not a closed system. This can be filed under "good news", I think, because it posits the existence of extra-universal energy sources.

Unless someone is using us as a ZPM. That would be bad news.

[Winston Blake]

These astronomers are meddling in things beyond the ken of man.

This 'dark flow' outside the universe is nothing less than the so-called 'Crawling Chaos', the so-called 'Outer God', NYARLATHOTEP, servant of AZATHOTH.

THEY FEEL OUR FEEBLE MIND'S EYE UPON THEM, AND WOE TO US, FOR THEIR GREAT EYES TURN UPON US IN RETURN.

[Solauren]

I wonder if what we know of the universe, is just one of many 'clumps' in the same universe.

In much the way we view galaxies as part of the universe.

Just the distances are so bloody huge, we haven't seen that far away yet (and may very well never will).

Which means, there could be another big bang happening in this universe, as few hundred billion light years away.

[Havok]

I wonder if what we know of the universe, is just one of many 'clumps' in the same universe.

In much the way we view galaxies as part of the universe.

Just the distances are so bloody huge, we haven't seen that far away yet (and may very well never will).

Which means, there could be another big bang happening in this universe, as few hundred billion light years away.

This was how I was thinking of it. Except I didn't give any consideration to the possibility of multiple Big Bangs. Interesting.

[Shroom Man 777]

Considering that what we're seeing is limited by the speed of light, what we're seeing is really oooold news. Like, countless billions of years outdated. I wonder what we'd say if we saw the present state of the universe as it currently is. Would it be wonderful, or would it be something existentially horrifying?

Probably both.

[Solauren]

That would be cool shroomy.

Get on making 100,000,000,000,000,000,000,000 FLT Sensors for us to do it with.

[Junghalli]

Considering that what we're seeing is limited by the speed of light, what we're seeing is really oooold news. Like, countless billions of years outdated. I wonder what we'd say if we saw the present state of the universe as it currently is.

The quasars would have all turned into normal galaxies?

[Count Chocula]

Back to topic, and blatantly displaying my ignorance, are there any current theories that our universe is actually larger than we can see? That is, are there any theories about the size of the universe being larger than the visible volume that are consistent WRT Relativity and Quantum Theory?

[starslayer]

Back to topic, and blatantly displaying my ignorance, are there any current theories that our universe is actually larger than we can see? That is, are there any theories about the size of the universe being larger than the visible volume that are consistent WRT Relativity and Quantum Theory?

Yes. Going by current models of inflation and the resulting Big Bang expansion, the full universe is much larger than the currently observable universe. Accounting for the redshifting of light that we see, the OU is roughly 45 Gly (45 billion light years) across at present; the true universe is anywhere from several hundred to several million or billion times that size, although we really don't know. More than likely, the figure would tend toward the upper end of that range, but we will never be able to see it. GR and QM really don't have much to say on the subject, except that those unknowable regions are most likely the same as our little corner on the extremely large and extremely small scales.