@sonhouse saidNobody on here that claimed the universe is expanding faster than c is a scientist. If a scientist was on this forum I would ask him/her.
@Metal-Brain
Thus continuing the troll network. Why don't you ask a scientist why they think the universe is expanding faster than c? That just means we can only see maybe a third of the actual universe because light from say 30 billion light years away just cannot reach us EVER so all we can see is about 14 billion light years out but of course you in your infinite wisdom cannot accept that as an answer so keep the bell trolling.
" That just means we can only see maybe a third of the actual universe because light from say 30 billion light years away just cannot reach us EVER"
That means that if there are galaxies over 40 billion light years away we cannot possibly see the evidence that the universe is at least 40 billion years old. So how do you know the universe is less than 40 billion years old?
Ignore contradictions much?
@sonhouse saidI don't know. You said we cannot see the whole universe because it is expanding faster than the speed of light. If that is true that means nobody knows. Right?
@Metal-Brain
Since you are the expert, please tell us how old the universe is.
@metal-brain said"It's okay if you don't understand physics at all. Just say so and stop wasting our time." -- Suzianne
I don't know. You said we cannot see the whole universe because it is expanding faster than the speed of light. If that is true that means nobody knows. Right?
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@suzianne saidQuoting yourself is not a classy move, especially when replying to that there.
"It's okay if you don't understand physics at all. Just say so and stop wasting our time." -- Suzianne
@Shallow-Blue
The thought rings true even if you don't like the signature.
But of course someone like metallic brainless would say HE is the maven here not Suze, not sonhouse, not you, ONLY he knows how it really goes.
@metal-brain saidFaster than the speed of light, or so I'm told.
How fast is the universe expanding?
The explanation for how this can happen is intriguing, given that nothing can travel faster than light. Faster than c expansion of space is supposed to be the reason objects seem to violate the universal speed limit. But I'm not so sure about this explanation.
I could for example claim an increased distance between myself and someone else is not due to either of us moving away from one another, but is due rather to the expansion of space between us. This would be a trick of semantics, to make it appear it has to be one or the other but not both.
Did I move away from you, or did the space between us become greater?
@sonhouse saidA faster than light accelerating expansion is problematic if it means objects within that expanding space are also (in effect) moving away from us (our locality) faster than the speed of light. What I'm suggesting is that instead of saying there are stars and galaxies moving away from our earthly vantage point at greater than c, which is supposed to be impossible, it's safer for scientists to say it is only the space inhabited by those stars and galaxies that is expanding faster than light.
@Kilroy70
The expansion doesn't effect local geography like our solar system. It is not like every atom is split apart, gravity is not strong enough for that so the only effect is to separate galaxies from each other basically.
Imagine driving so fast you blow by a police car going the posted speed limit. You were obviously going too fast so the officer pulls you over for speeding. I could say, "But officer, I wasn't going faster than you. It was the space between us that was expanding at a high rate of speed, so it only looked like I was going too fast." 🙃
Space:
A_B_________C
Space expanding:
A_.B_._._._._._._._._C
A_..B_.._.._.._.._.._.._.._.._C
A_...B_..._..._..._..._..._..._..._..._C
.
.
.
A_.......B_......._......._......._......._......._......._......._......._C
The point B started out closer to point A than point C was to A. But, locally, space is thought to expand at the same rate everywhere. As a result, a point like C that is farther from A to begin with will recede from A at a greater rate than points like B that are closer to A to begin with.
We can see above how B "moves" less far away from A over a given time interval than C "moves." There is no theoretical limit to this dynamic, and so if C is far enough away from A it could conceivably be that C "moves" away from A at a speed greater than the speed of light. A light signal from C would then never reach A because the path to A that the light must travel is getting longer faster than the light can move along the path.
As for what space "is," I like to think of it as an emergent property of the myriad quantum entanglements between all particles in the universe, which our minds naturally arrange from visual input so as to be perceived as "near" or "far," thereby giving rise to our everyday three-dimensional spatial construct.
The more entangled two particles are, the "closer together" they are; the less entangled they are, the "farther apart" they are. There is no "spooky action at a distance," because distance is a function of action, and action is a result of entanglement.
@Kilroy70
I think of it kind of like we are on two conveyer belts moving in opposite direction, you can see the two end to end one going left the other say going right, so we get on them, you on one me on the other, then the conveyer starts up, we are separating but we ourselves are not moving in our local setting. So the conveyer belt can go way over the speed of light, that would be spacetime, it could care less about the limit of speed of light stuff, spacetime ignores all that and can move as fast as it has the energy to do so.
It started out (as the BB theory goes) with an incredible stockpile of energy in the original expansion but the expansion never stopped just slowed down from it's start running about 22 orders of magnitude faster than c at the start to what we think is about 3 or 4 times c now.
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@soothfast saidhttps://tvtropes.org/pmwiki/pmwiki.php/Main/MeaninglessMeaningfulWords
As for what space "is," I like to think of it as an emergent property of the myriad quantum entanglements between all particles in the universe, which our minds naturally arrange from visual input so as to be perceived as "near" or "far," thereby giving rise to our everyday three-dimensional spatial construct.
@shallow-blue saidNo, you do not understand.
https://tvtropes.org/pmwiki/pmwiki.php/Main/MeaninglessMeaningfulWords
Physics needs to start tackling the big questions: what exactly is space, and what exactly is time?
Right now, it's precisely the words "space" and "time" that are meaningless terms when used on the (quite literally) most universal scale. Typically they're the stage on which physics plays out, but stand oddly apart from physics itself. That is not acceptable in this day and age. Very smart physicists are increasingly asking the question: Does time really exist, or is it just a bookkeeping device to organize our thoughts and perceptions? And what is space? To even begin to answer these questions, we must be clear what exactly we mean by time and space. The everyday meanings used for scheduling a meeting doesn't cut it. Space and time figure in countless physical models, but themselves have no explanation. Relativity models the shape of spacetime on a large scale, but says nothing about what is being shaped.
I purpose to address the true mystic here directly. That would be you, old bean. You are part of the problem with physics being stuck in a rut, because you're grafting Newtonian-era constructs onto quantum chimera as if trying to dress your shadow in your Sunday best. When we speak of "space expanding," the question should naturally arise: what precisely is expanding when "space" is expanding?
Well, we must come to grips with quantum entanglement. We see in experiments that particles thousands of miles apart seem to interact (or communicate) instantly. They are "entangled," and at first glance it suggests that information can travel faster than the speed of light. But there is a loophole that saves Einstein: useful information cannot be conveyed by entangled systems by any means we can currently devise or even divine. Nonetheless we see instant effects on a faraway particle when one near at hand is changed in some way, if the particles have become entangled.
It has been posited that what we perceive as "near" or "far" is not really a function of what we understand to be spatial separation (i.e. "distance"​) in the usual sense*, but rather the geometry of space as our senses perceive it is really like a graph. Here I speak of the graphs of graph theory, not the graphs of a high school algebra class. This conception of the "fabric of space" presents it with edges and nodes, with nodes being particles, and edges connecting particles in accord with entanglement properties. Greater entanglement makes things appear "closer" to our senses, lesser entanglement makes things appear "farther," and things we cannot perceive at all (owing to distance or being hidden by other particles) are things that are not sufficiently entangled with our sense organs for us to be able to discern them. Time fits easily into this scheme, and indeed the scheme meshes with common sense insofar as it's sensible that things we are not in physical connection with are invisible to us and may as well be "infinitely far."
In any case the purpose of a physical model is to find a mathematically useful way to describe a physical phenomenon that elicits more useful information than what raw data about the phenomenon itself can convey. To view spacetime as a graph consisting of nodes and edges representing particles and their entanglements stands a chance of helping connect the large-scale universe with the quantum realm, perhaps to at last attain the holy grail of unifying quantum theory with gravitation. This is the primary motivation for modeling spacetime using graph theory constructs.
Physics fared better back in the age when physicists frequently had a strong background in philosophy. We are in bad need of this now, because modern physics has come to the juncture of matter, energy, and thought. How our very thought may color our perception of reality, indeed how our unexamined habits of thought (e.g. spacetime is a stage for physics that's apart from physics), may very well be what's blocking humanity from achieving the next great breakthrough.
* Here's some of that mysticism: "empty space" creating a separation between objects somehow. Huh! Not good enough for honest scientific sensibilities in the quantum age. What's that "emptiness's" secret for doing so?