Is the Universe a perpetual motion machine?

[peter]

I've probably asked this before, but in the light of evidence that the expansion of the Universe is actually accelerating rather than static or slowing down (I refer to the expansion with those terms not the Universe of itself), how does this effect the thing that the net energy of the Universe is always zero........and if the Universe wasn't a perpetual motion system before (in it's zero energy balance state) then is it one now? If it is, and there's a prize do I get the money? Do dark matter and dark energy follow the e = MC squared relationship and like, cancel each other out or something?

[Vraith]

Expansion and zero net energy may be consistent with each other. All the stretched/pushed/new space that comes to be ALSO involves new negative/gravitational energy, so the balance remains. [[there's at least one other way to balance it, too...but I don't get it at all, so far]].

OTOH...some argue [and some models show, and some problems are solved if] the universe probably has a very [VERY!] slight positive energy...
There are a couple different ways to get that, too...all of which are way beyond me. The major distinction that's easy to understand is some of them do it with a closed system universe, and some with universe at least partially open [which means most conservation laws don't HAVE to apply in every single instance].

Dark matter and dark energy don't necessarily have any connection to each other at all [[though both are part of your first question...in different ways...about net energy and expansion..]]. A "dark electron" that changes state/energy doesn't emit dark energy. They're only both called dark cuz we don't know what they are. Fun fact...we ALSO don't know, at a fundamental level what "light" energy is, either...we just know even less about the dark stuff.
BUT---it seems both must follow the formula, or the universe as we see it wouldn't exist...or if it DID exist and look like it does then literally every single thing we "know" would be literally and absolutely false.

[peter]

Just to clarify V, does 'open or closed' in respect of universe type refer to whether it is 'hermetically sealed' (as it were) in terms of energy input from 'outside' (ie closed), or whether energy could come in from outside (whatever that is), if it were the open model, or is it more to do with whether the universe expands and then contracts rather than just expanding forever?

In respect of dark energy and matter, would I be correct in thinking that more than just being dark because we can't see them, they don't actually have to be matter or energy as we understand them at all (and in the case of energy, from what you say above, that seems pretty little at best) anyway. Is it not the case that we 'slot' energy and matter (matter in particular) into the picture, because they are the only means by which we can reconcile our current understanding of how the universe works (call it the paradigm) with the observations we make?

[Vraith]

Just to clarify V, does 'open or closed' in respect of universe type refer to whether it is 'hermetically sealed' (as it were) in terms of energy input from 'outside' (ie closed), or whether energy could come in from outside (whatever that is), if it were the open model, or is it more to do with whether the universe expands and then contracts rather than just expanding forever?

In respect of dark energy and matter, would I be correct in thinking that more than just being dark because we can't see them, they don't actually have to be matter or energy as we understand them at all (and in the case of energy, from what you say above, that seems pretty little at best) anyway. Is it not the case that we 'slot' energy and matter (matter in particular) into the picture, because they are the only means by which we can reconcile our current understanding of how the universe works (call it the paradigm) with the observations we make?

Far as I can tell, closed always means sealed, as you say. But closed can still be infinitely expanding, or cyclical [[steady state is also closed but the evidence seems to be that steady state is the one option most certainly excluded from being the actual state]].
Open seems tied to string and brane theories---I think that's the only place I've seen them [definitely the only places I could figure out that that's what might be meant...though not all of those families necessarily mean/require open.]

Also, far as I can tell, dark matter is almost certainly a kind of matter, it's just very picky/limited in properties/interactions with the more normal stuff...it's a bit weird, but probably at least a kissing cousin to the stuff we're used to. Apparently a couple options for what dark matter is can [and will] be explored by the L. Hadron Collider.
[[[one alternative to that, though, is that gravity doesn't actually work the same everywhere. Then it becomes as strange as dark energy. There have been a couple measurements/tests that that view has failed, so it seems mostly, but not totally, out]]].

Dark energy is a non-horse of a different un-color.
In a way...loosely...it's kinda like genetics before science/biology/tech.
Almost everyone KNEW traits could carry through generations, and traits could vanish over generations, and even figured out you could breed better corn, better dogs, etc. But had no idea, or even an idea about an idea of an idea what was going on...barely knew what organs were---and they could see those. Not an inkling about cells, let alone sub-cellular, and no way to even think about thinking about making tools to look for them. And DNA several removes more from thinkable. Yet SOMETHING had to be doing what they could clearly see was the actual fact of plants and animals.

[peter]

Good explanations V. Gratitude. We know that math is a language that doesn't easily translate into common tongue and I wonder if the 'pictures' of what these things are, how they work, are not much clearer when physicists actually communicate with each other using the symbols in which these ideas are framed.

One last thing that has been grumbling on the edges of my understanding of late, can you tell me if inflationary theory sits inside the big bang theory (as in, the big bang happens, then the Universe undergoes either a steady expansion or a short rapid burst of inflation followed by a slowing to a lower rate {the latter being inflationary theory}) - or are the two completely different theories with different starting points? I thought I had it down that inflationary theory was just about how the expansion of the universe proceeded subsequent to the big bang, But Bill Bryson, in his book A Short History of Nearly Everything seems to imply otherwise on the first page of chapter 1, and now I'm not so sure.

[Vraith]

I thought I had it down that inflationary theory was just about how the expansion of the universe proceeded subsequent to the big bang,

All the most recent things I've seen [I was just reading about this at a site called "Starts with a Bang," a week or two ago, for instance] say that's exactly backwards. Inflation happens FIRST, the BB---all the normal stuff, or at least the very hot stuff that all the later normal stuff is made up/cooled down from---happens after [though only the tiniest fraction of a second after]. In several of them they say that all the "stuff" of the BB condensed out of the inflationary fabric.

AND...though none I read were talking about this particular thing, I just noticed it...the nature of that inflating space shares a very specific property with Dark Energy...unlike all other radiation/energy/matter that exists, when the space expands, the DENSITY remains constant. [for normal stuff, matter density falls with the cube, radiation falls with the fourth, for dark energy, the density doesn't fall AT ALL...

of course SOMETHING happened, cuz the inflation slowed dramatically/suddenly...the density DID drop, apparently, that once.

PERHAPS, the condensation/coming into ordinary stuff caused that, but I'm just making that up.

Perhaps whatever it was and dark energy are related, but not identical...

or perhaps they just happen to have that one property in common.

I don't think anyone knows if, why, or how all our normal stuff would convert from the weirder state...but that seems more likely than coming out of nowhere...and not just in one place, but in all the places at the same time. And all being the same KIND of stuff out of nowhere.

[peter]

But put in a nutshell, just so I have this, inflationary theory and big bang theory are not mutually exclusive theories - either one or the other - but more a case of being intertwined models with space-time and regular versus inflationary expansion being the players.

[Vraith]

But put in a nutshell, just so I have this, inflationary theory and big bang theory are not mutually exclusive theories - either one or the other - but more a case of being intertwined models with space-time and regular versus inflationary expansion being the players.

If I'm reading you right, AND if I'm understanding the current debates/models right...then, not exactly.
They aren't mutually exclusive, true.
But there is no "versus" either.
They're one thing...or different phases/transitions of one thing...or one [inflation] causes/permits the second. [BB].
IF the BB itself is correctly described, it cannot produce/evolve into the universe we see. It MUST be either:

paired/complemented with/evolve from something else...and inflation is the thing that--at least currently---explains what we see the best.

OR
Almost completely wrong description.
The things we know almost for sure about the BB itself cannot get us here from there without something else.

And it seems a wrongness that is too far...
I mean, like I might have said before, I can imagine a Newton vs Einstein gravity wrong...
But I can't imagine an "Odin and friends built the world from the corpse of the First Giant, Ymir" wrongness.

[peter]

Got it! (....ish. ) Food for thought!

[peter]

I have to admit that a part of me is slightly disappointed to have to loose the BIG BANG! as the crash into being of the singularity from whence everything.........., it has a sort of satisfaction element in terms of onomatopoeic visualisation of this event. "It started with an inflation......" alas has not the 'theatre' of "It started with a bang....". But on the plus side, I can now bend my attention to coming up with a suitable name for the origin event to feed into the public lexicon. Ahead of me (like unto the event itself) lie a universe of possibilities with which I can at last make my allbeit anonymous mark on posterity.

[Ur Dead]

What is an explosion? It's a expansion of something. Gases/waves of energy
in the case of it happening here. What sound does it make? The easiest
human sound to make is ...BANG. So the sudden expansion of space/time is
repeated on much smaller scale in planets and stars. When a meteor hits a
planet and normally it breaks apart violently or impacts the surface we label
it an explosion. What easy sound word describes the sound? When a star
explodes.
It is a sudden expansion of gases and material. If there were an atmosphere
surrounding it would it make a noise? Most likely and the sound could be
describe as the word BANG. (Much more louder and ear splitting)

So just because a few bozos who can't come up with a better theory on how
the universe was created want to change the whole perception of the
current accepted theory is is a flaw in their mental abilities. So I will keep
calling it the Big Bang. (and I don't care how smart or famous they are,
they're still bozos)

As far as a perpetual motion universe, you would have to believe in another
theory of how the universe was created. That is the Steady State theory.
Perpetual motion is creation of something from nothing(or more energy than
used) and the S.S. fit that. But that theory has been abandoned by the
majority. So... the current accepted theory disproves the the idea.

Explaining the acceleration of the universe by the current accepted theory
can simply be said as two magnets facing each other with the same poles.
The closer they are the more repelling force there is until both magnets are
at a distance where there the mag force can no longer push the other
object. The universe may not be at that point. But also that one magnet in
it's repelling movement may spin and then you have attracting forces and
he magnets may move together and may combine.

So there is dark matter and dark energy and they don't know what either is.
Wow... One keep the galaxies together and the other pushes them apart.
Both may be a part of the same coin. The first law of thermodynamics might
detail what happens to each without understanding the nature of both.
They may change but not all at once.
Like now happening on our world with the polar reversal. The field weaken to
a point where the align portion splits apart and suddenly you have a number
of north and south poles all over the place. The planet has a magnetic field,
it weaker than the aligned one but protect the life there. There has been a
number of flips over the millions of years. It been measured but there is no
indication of mass extinction during those flips. But the Auroras are going to
be all over place during that time. Wouldn't that be something to see.

/Disclaimer: The following is an expression of the poster. No brain cells were harmed during it's writing.

[Cord Hurn]

I think you've managed to expand my brain cells without exploding them, Ur Dead! And for that, I am grateful!

[peter]

Or is it just the space between them that is expanding CH?

[Ur Dead]

Could be the dark energy causing expansion?

[Vraith]

So just because a few bozos who can't come up with a better theory on how
the universe was created want to change the whole perception of the
current accepted theory is is a flaw in their mental abilities. So I will keep
calling it the Big Bang. (and I don't care how smart or famous they are,
they're still bozos)

Now that's just silly [though it was fun]...no one wants to change the perception just because they have flawed brains.
It's not that they can't come up with a better theory than the old one...it's that their version IS a better theory...and for some reason you don't like it.

But really, you don't have to give up the bang---it still exists/happens---inflation is about how/where it blows up.

If you want a [physically/literally wrong...but that's what meta phor] analogy...think of it like a real explosion...you see it before you hear it [unless you're too close...then you just instantly become a mist that never sees or hears anything at all which is precisely what would happen to any atmosphere and person in it that existed around the big bang]...think of inflation as the flash part of flash/bang.

Your magnet thing isn't totally out, though [though like my analogy, it's literally/physically inaccurate, probably] because we know the rate of inflation has changed, enormously, at least once. and some have pondered the idea it might change rate---or even flip directions---at some other/future point. [[A thing C. Hurn should be hoping for...otherwise, though un-torn in expansion at the moment, rent asunder is the future of his brain if dark energy is the cause....]]

[[there are several reasons why that...CH brain shredding AND direction-flipping...seems ridiculously unlikely, but given what we don't know it can't be completely excluded yet]]

[Ur Dead]

Other theories

https://youtu.be/V5LE0hNmJ90

[Vraith]

Other theories

https://youtu.be/V5LE0hNmJ90

WOW!---that narrator has one of the weirdest/worst voices/deliveries I've ever heard! It's like the guy who sang the original Mr. Grinch song took a bunch of Valium and tried to do an impression of a Victorian-era Pompous Russian with English Second Language giving a lecture on wine-service to a member of the lower classes.

I've run across all those theories except the big freeze one.
The thing is, they all suffer from similar kinds of problems..they all have at least one, often several of:

They create more problems than they solve...
[[if you think dark matter/energy are weird, you should see what THOSE require]]
They fail to explain/predict things we see that the current model does...
They predict things we should see but don't...
Some are untestable even in principle.

None of which means there isn't a workable option among them that could be expanded/modified with new info
Nor that the current one is dead right [I doubt that...but whatever replaces it will have something inflation-esque and bang-ish].


[[Aside: I love/hate Elon Musk for a variety of reasons...but simulated universe seems dead. Someone did the math/comp. science. I don't recall the exact numbers, but it was exponential and something like---
a computer to perfectly/completely model 100 particles would require a memory with more atoms than the universe. If you increase that to 101 particles, you'd need twice again that memory. So at 105 particles, you need 64times the atoms in the universe, at 110 particles you'd need over 2THOUSAND times the universe, at 120 particles, you need 16Million universes...[[I stopped at 120, cuz that's the number of normal particles in an atom of Krypton, I believe, and it starts taking a superman to keep really understanding numbers much beyond this...]]

[Skyweir]

https://www.bing.com/videos/search?q=mo ... &FORM=VIRE

Just remember that you're standing on a planet that's evolving
And revolving at nine hundred miles an hour,
That's orbiting at nineteen miles a second, so it's reckoned,
A sun that is the source of all our power.
The sun and you and me and all the stars that we can see
Are moving at a million miles a day
In an outer spiral arm, at forty thousand miles an hour,
Of the galaxy we call the 'Milky Way'.
Our galaxy itself contains a hundred billion stars.
It's a hundred thousand light years side to side.
It bulges in the middle, sixteen thousand light years thick,
But out by us, it's just three thousand light years wide.
We're thirty thousand light years from galactic central point.
We go 'round every two hundred million years,
And our galaxy is only one of millions of billions
In this amazing and expanding universe.

The universe itself keeps on expanding and expanding
In all of the directions it can whizz
As fast as it can go, at the speed of light, you know,
Twelve million miles a minute, and that's the fastest speed there is.
So remember, when you're feeling very small and insecure,
How amazingly unlikely is your birth,
And pray that there's intelligent life somewhere up in space,
'Cause there's bugger all down here on Earth.

[Vraith]

https://www.bing.com/videos/search?q=mo ... &FORM=VIRE

I love Python songs.

OH, Ur-dead---I meant to mention, the "Rainbow Gravity" one MIGHT get a test, or at least a hint.
The data has been collected and is being crunched of the first real attempt to image a black hole [well...it's event horizon]. It should be released soon-ish, I hear [early/mid 2019]
Anyway, they're using radio telescopes that I'm not sure have a wide enough spectrum or sensitivity to detect the differential bending...but maybe?? I don't know the exact tech specs. And of course, that's not an effect they're looking for, so they might not have/be using the right data tools.
It's at least theoretically possible to check that one, though.

[Skyweir]

Such a clever dude thee be V ..

A love of Monty Python AND all things sciencey.. and philosophy! I just learned .. yes Im a long way brhind the 8 ball that Philosophy means wisdom .. the pursuit of or study of ... that gave me a completely different perspective clever huh?