Is there space inside objects like planets? If so, do we see an increase in the size of the planets over time?New space is being added everywhere. — Pfhorrest
Is there space inside objects like planets? If so, do we see an increase in the size of the planets over time? — SimpleUser
There is space yes, but we don’t see small things (where even a galaxy is “small” for these purposes) expand because on small scales the forces holding those things together completely dwarf the force of expansion. — Pfhorrest
The big bang theory does not posit an explosion into space from some point in that space. Any simple description on the web will tell you this. The expansion of the universe is not a speed, and is measured in different units. Pfhorrest seems to know the physics.If we first assume the universe started with a Big Bang, then there should have been a shock-wave extending out from the center. — Don Wade
Science says no such thing. It makes no mention of a shock wave, which is something you get from say a star exploding in space. The universe isn't an object in space like a star.Science tells us that the shock-wave could not move faster than the speed of light. Did it?
The diameter of the visible part of the universe is about that. That volume includes all the material that can possibly ever have had a causal effect on us today. It doesn't mean we can see that far. Any light that has ever reached Earth up until the present has never been further from us than a proper distance of under 6 billion light years. Measured that way, the size of the visible universe is under a 6 BLY radius. We can only see these really distant galaxies because they were much closer than that distance back when they emitted the light that we're seeing now.the diameter of the universe is about 90 billion light years — T Clark
Again, the expansion rate is expressed in different units and thus is not a speed and cannot be meaningfully compared using a word like 'superluminal'.Under all circumstances then, and unless the rate of expansion slows considerably enough to no longer appear superluminal — Vessuvius
A reasonable definition, but still dependent on serveral assumptions such as your chosen interpretation of QM. An MWI guy for instance might say that the universe is the one universal wave function. Any follower of a realist interpretation (MWI being one of them) might say that the universe is all that is. I learn towards the RQM side, but I'm hesitant to say the universe is all that I measure since that confines it to the visible universe, and it needs to be meaningful to talk about more distant things, however much those things don't relate to us.Then what is the universe? That is, something other than it started with a big bang. — Don Wade
No model supports that. It is a naive interpretation that is quickly falsified.Does the universe exist in space
Time as well since it is the same thing. Few can get their heads around time being part of the universe rather than the universe existing in time, which reduces its ontology to that of a mere object.or does space exist in the universe?
Great example of trying to think of the universe as being contained by time. The universe is not an object. Spacetime is part of the structure that is the universe.Which came first, space, or the universe?
The rate of increase in proper separation of a sufficiently distant (and visible) galaxy does indeed increase at a rate greater than c, but this still isn't superluminal since the light emitted by that galaxy in a direction away from us is moving away from us even faster. Nothing is outrunning any local light as you know.but as seen from the perspective of a fixed observer, relative to some far off point which is of so large a scale as to make the effects of such expansion dominate, for all intents and purposes it does appear to the observer as though a superluminal velocity is attained. — Vessuvius
I did, but there's not much appearance to it. We see redshift and brightness, both of which approach infinity and zero respecitively with subluminal local motion, and from that glean the speed. If we wait long enough, we see the object get smaller over time, but not so much that it appears to move super fast. Take GN-z11 which at redshift z=11 is the most distant galaxy know. Yet it subtends an angle that places it only about 3 billion light years away, making it appear to move quite slowly actually. Speed from appearances is a calculation relative to a model and a coordinate system, not something that can be directly measured just by looking at it.Do notice how I qualified my statement with likening its chosen object only as appearance, rather than an absolute.
Good grief, I never caught a suggestion of that in your posts.As my argument certainly wasn't that this reference frame is somehow privileged, or the only one of merit.
You're talking about objects outside the visible universe? A few will become visible as that radius expands, but most never will. As a non-realist, I cannot say that any of those objects specifically exist relative to us, but someone positing an objective state of the entire universe would say that these distant objects do exist, any one of which is receding from us at an arbitrarily high rate.The purpose for which I cited it was instead to highlight how ideas of causality are meaningless in these cases because the light-cone of the observer is forever prevented from accessing the image of such distant point-sources, and nothing more.
It is thence a rather misleading characterization to say that the universe "started" with the Big Bang, as it always existed beforehand, just in a state so unlike anything we can conceive that one cannot speak of it meaningfully. — Vessuvius
The inflation of space was a notion dreamt up purely to preserve the notion of a fixed value for the speed of light as currently measured. It has no evidence to support it and only exists to preserve doctrine over substance. — Gary Enfield
Indeed, in this respect, relativity is open to too many variables to provide a comment on this - when by its nature, any 'absolute factor' must take precedence over relative readings. The width of the universe is such an absolute - and a figure that wasn't available to Einstein. — Gary Enfield
What you're asserting then, is that the near entirety of Inflationary Cosmology, as physicists apprehend it today, is a facade. — Aryamoy Mitra
You can't straddle between two, antithetical narratives. Either abnegate General Relativity, and be a proponent of nonstandard ideas - or accept it, — Aryamoy Mitra
I think I can just about guess what this jargon means - but you seem to be suggesting that I am jumping around between theories, when I am not. I am simply saying that the evidence of distance divided by time - when applied to absolute and agreed values, trumps vague notions based on doctrine over real substance. — Gary Enfield
As I said before. I acknowledge that your preferred theory may one day be given substance, but it hasn't yet - and the historical fact remains - it was dreamt up to preserve a fixed C — Gary Enfield
Unsatisfied in the case of uniform distribution everywhere. The level of compression has nothing to do with it. The current density of the universe (about 6 protons per cubic meter) is enough to prevent expansion if it was that mass expanding into empty space. None of the material would have sufficient recession speed to exceed the escape velocity of the bounded mass that comprised the occupied part of the universe.unsatisfied in the case of a mass subject to an arbitrarily high-degree of compression — Vessuvius
Science is confident about the minimum size of the universe today in absolute terms. It is also confident about what the speed of light can achieve in normal circumstances today. Clearly the maths which T Clark pointed out is self explanatory if you believe in the Big Bang. The universe must, in absolute terms, have expanded faster than the recognised maximum speed of light. — Gary Enfield
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