Can light slow down?

Originally posted by CLPrime
reply to post by ImaFungi

 

The convention is that it will get spread so thin that there will be nothing more than a sparse field of photons in otherwise empty space. This is due to the continual expansion of the universe.

The expansion of the universe occurs everywhere, but gravity counteracts it. So, inside galaxies, space isn't expanding between the gravity inside the galaxy is preventing it. That's essentially why we only see space expanding between galaxies and larger structures -- the gravitational force within these structures are holding them together.

wouldnt the mass of the galaxies and structures effect the speed/rate of expansion in different areas?

"This is due to the continual expansion of the universe."

the only reason the universe is expanding,, is because the momentum from the big bang and clusters of mass increasing as galaxies allowing for greater velocity?

if the gravitational force holds galaxies together so well,, and there is so much energy within them,, is it not possible for galaxies to recycle their energy forever? the rotation of the galaxy and all the soloar systems gravitationally following and pushing and pulling all others,, stars dyeing and giving birth to new,, eventually there will be no way to create new stars in a galaxy?

Originally posted by ImaFungi

wouldnt the mass of the galaxies and structures effect the speed/rate of expansion in different areas?

Yep, it does. But the effect is negligible, as much of the universe is empty space.

the only reason the universe is expanding,, is because the momentum from the big bang and clusters of mass increasing as galaxies allowing for greater velocity?

Not quite. The universe isn't expanding due to momentum from some initial explosion. The cause of the universal expansion is the cosmological constant in Einstein's field equations. This could be any number of things, but my preferred theory is that it's energy being released by the collapse of a quantum vacuum. That energy is often called zero-point energy, though it's been my experience that most people who use that term have no idea what it means. Zero-point energy is the energy contained within a quantum vacuum, which it can release as it collapses to a lower energy level. That's the difference between a classical vacuum and a quantum vacuum -- a classical vacuum is a simply a complete absence of any matter or energy, while a quantum vacuum can have "hidden" energy. In simplistic terms, the floor can drop out of a quantum vacuum, causing a release of energy. The idea is, it's this release of energy that causes the universe to expand. This energy would then condense to form matter, possibly explaining where matter comes from.

This energy release would likely be an ongoing event.

if the gravitational force holds galaxies together so well,, and there is so much energy within them,, is it not possible for galaxies to recycle their energy forever? the rotation of the galaxy and all the soloar systems gravitationally following and pushing and pulling all others,, stars dyeing and giving birth to new,, eventually there will be no way to create new stars in a galaxy?

Eventually, galaxies will collapse to form black holes, which will then evaporate. Galaxies aren't really all that stable, they just appear that way because, as humans, we're not around for very long.

If the Universe is expanding - what is it expanding into - a vacuem of nothingness or a quantum vacuem
It would seem to me that there is no such thing as nothing - that nothing is something?

reply to post by artistpoet


My answer to that would be that the universe is probably infinite in size. So, it's not expanding "into" anything because there's is no "outside." The universe is all of what physically exists, out to infinity in every direction.

That's what I would say.

Originally posted by CLPrime
reply to post by artistpoet

 

My answer to that would be that the universe is probably infinite in size. So, it's not expanding "into" anything because there's is no "outside." The universe is all of what physically exists, out to infinity in every direction.

That's what I would say.

Makes sense to me in a mind blowing sort of way.
So if we are looking at an infinite Universe of larger and larger structure - looking at the microcosm would you say that this is also infinitely small and smaller

reply to post by artistpoet


Depends what you mean by "microcosm." It would seem that the universe has a lower size limit (the basis of Quantum Mechanics). We also find that this limit is, observationally, bigger than we expect it to be given quantum theory. That fact is used as evidence for the Holographic Principle -- which says the entire 3D universe is just a holographic illusion of a 2D reality projected on the inner surface of a sphere.

So, with that, I suppose you can picture God sitting in his la-z-boy with a sphere in his hand...and, on the inner surface of that sphere, a slide projector-like image causing a holographic 3D movie on the interior space. And somewhere in there is us -- just a holographic 3D projection of a simple 2D reality.

How's that for mind blowing?

reply to post by CLPrime


"Zero-point energy is the energy contained within a quantum vacuum, which it can release as it collapses to a lower energy level. That's the difference between a classical vacuum and a quantum vacuum -- a classical vacuum is a simply a complete absence of any matter or energy, while a quantum vacuum can have "hidden" energy. In simplistic terms, the floor can drop out of a quantum vacuum, causing a release of energy. The idea is, it's this release of energy that causes the universe to expand. This energy would then condense to form matter, possibly explaining where matter comes from.

This energy release would likely be an ongoing event. "

wouldnt there be some cause for there being quantum vacuum hidden energy,, wouldnt that cause be the constant movement of all things physical as and within the universe? i cant imagine the reason for there being fluctuations of energy in what is seemingly empty vacuum space,, because thats just what happens in quantum vacuums,, i think that energy detected in seemingly vaccant space is most likely from some near by cosmic event,, or an event that took place in the space that is being detected and there are still lingering particles and energy,,,,, if space is expanding and thers depris and radiation and energy being flung in all and every direction and these particles of energy are just doing their thing in space and space is stretching and expanding we can measure an area of space and detect particles and energy,, i think its because of all the events that go around surrounding our detection..... i know that isnt a professional, classy, or coherent way of stating that idea but do you understand what im trying to say and do you completly disagree?

so the big bang is not some explosive force? there is so much charge, and power,,,, tremendous,,,, in my mind i always imagined when people talked of the big bang,,, an explosion of all things outward and that is why there is so much distance and continueing distance, and that prime jumpstart is what caused the galaxies to swirl and move so quickly etc...... i dont neccesarily believe whole heartedly in the current model of the big bang theory,,, but the universe did get it self here somehow,

Originally posted by CLPrime
reply to post by artistpoet

 

Depends what you mean by "microcosm." It would seem that the universe has a lower size limit (the basis of Quantum Mechanics). We also find that this limit is, observationally, bigger than we expect it to be given quantum theory. That fact is used as evidence for the Holographic Principle -- which says the entire 3D universe is just a holographic illusion of a 2D reality projected on the inner surface of a sphere.

So, with that, I suppose you can picture God sitting in his la-z-boy with a sphere in his hand...and, on the inner surface of that sphere, a slide projector-like image causing a holographic 3D movie on the interior space. And somewhere in there is us -- just a holographic 3D projection of a simple 2D reality.

How's that for mind blowing?

Yes I have heard that theory or idea before and yes it blows my 2D or is it 3D mind
Also made me laugh as it could well be so.

reply to post by ImaFungi


The Big Bang, according to current theory, was not an explosion. It was a period of rapid inflation. I told artistpoet that I believe the universe is infinite. Is this is the case, then it has always been infinite. I'll get back to that in a sec...

First, here's how I usually explain the collapse of the quantum vacuum:
Imagine you're walking along outside. The ground is the lowest you can go. That represents a quantum vacuum... it's the lowest possible energy state of a system (for example, the early empty universe).
Now, imagine you're walking along and you fall through an abandoned mineshaft. The mine is lower than the ground. This is what happens when a quantum vacuum collapses... the lowest energy state gives way to an even lower energy state.
So, that's the collapse of the quantum vacuum. Now...

The initial universe was infinite and empty, filled only with a quantum vacuum. Spontaneously, that initial quantum vacuum collapsed to a lower energy level. This released a huge amount of energy (in fact, an infinite amount of energy throughout the infinite universe), which caused the universe to rapid expand. We call this the Inflation Epoch.
As the universe expanded, the energy cooled and condensed, forming particles. As these particles cooled further, they became the particles we observe today (everything from electrons to photons). These particles then condensed to form matter (atoms, molecules, compounds, and larger structures)...and the rest, as they say, is history.

reply to post by artistpoet


I doubt it...but it's fun to consider.
Personally, I have an aversion to String Theory.

"The Big Bang, according to current theory, was not an explosion. It was a period of rapid inflation"

"Spontaneously, that initial quantum vacuum collapsed to a lower energy level. This released a huge amount of energy (in fact, an infinite amount of energy throughout the infinite universe), which caused the universe to rapid expand. We call this the Inflation Epoch."


is an explosion a huge release of energy in which that energy rapidly inflates and expands?
its even called the big bang giving my mind the impression of rapid and immediate expansion of massive amounts of energy in an explosive sort of way....

reply to post by ImaFungi


It's called the Big Bang because they used to think it was an explosion. Since then, we've determined that it's actually a metric expansion. It's a stretching if space itself, not an explosion of the material in space.

The energy is not exploding anything, it's providing an anti-gravitational force that's causing space to stretch outward.

Originally posted by CLPrime
reply to post by ImaFungi

 

It's called the Big Bang because they used to think it was an explosion. Since then, we've determined that it's actually a metric expansion. It's a stretching if space itself, not an explosion of the material in space.

The energy is not exploding anything, it's providing an anti-gravitational force that's causing space to stretch outward.

what caused the materials of space to start epic orbits and cycles and travel at unbelievable speeds, what was the thrust that caused it to travel so fast,,,, i dont believe that space stretching stuff...... i think thats the biggest garbage... just because objects are locked with each other via gravity, the space in between the objects may be set in some way from all other extrnal forces acting upon it, the distance may increase, but i dont get the speaking of space, you believe is vaccumly empty, as an object it self,,

reply to post by ImaFungi


In all honesty, the evidences behind these theories are typically beyond the ability of most people to understand.

Metric expansion is required because of the uniform and isotropic nature of the universe all the way out to the CMB. A high degree of uniformity in the nature of the expansion is required to arrive at the observed current conditions. Metric (spatial) expansion is the only thing that satisfies this.

Things orbit because of gravity. Locally, gravity overcomes the force of expansion. Within galaxies (and other gravitational systems), the expansion is negligible because gravity is counteracting it.

The expansion of the universe is merely an opposite action to gravity, which warps space inwardly, creating wells" of gravitational potential. Universal expansion is just the opposite of this.

If there were an initial explosion, the current state of the universe would be highly disordered... random, even. On the contrary, the universe is highly ordered and uniform in all directions. This indicates a highly ordered expansion event, necessitating metric expansion. We can even map this uniform expansion with the Hubble constant, which shows that the expansion is extremely isotropic. This would not be the case had there been an initial explosion.

Also, the quantum vacuum is a consequence of quantum states. It's not a "thing," per se...nothing in Quantum Mechanics is a "thing," it's all wavefunctions and quantum states. Restrictions on energy levels are less defined than in classical physics. Take, for example, quantum tunnelling, and the realization that an electron is a wave existing probabilistically in any given location rather than explicitly at a given point in time.
The quantum vacuum is empty, but it can randomly "decide" to get "more empty."

"Take, for example, quantum tunnelling, and the realization that an electron is a wave existing probabilistically in any given location rather than explicitly at a given point in time. "

i think this is due to our perception..... if we could process time faster or were viewing our scale and bodies from a higher perspective,,, wouldnt our bodies be moving through time in orbits of habit, even while we are standing or sitting still, we are still moving through space and time?


"If there were an initial explosion, the current state of the universe would be highly disordered... random, even."

i dont think that is necessarily true,, couldnt it be there was an explosion and then everything was plasma and as it expanded further apart it started forming into how we view the universe today... so instead of a large explosion how do you think it would have been viewed the begginigs of the universe,, did this expansion happen fast? yet evenly and ordered?

"On the contrary, the universe is highly ordered and uniform in all directions. This indicates a highly ordered expansion event, "

was it the laws of physics that kept the matter and expansion in order? i think a random chaotic explosion can eventually lead to order and uniformity down the road.... if i spike a rock into a still lake in a random area, and we watched this event in super slow motion,, there would be a controlled area where drops of water would splash down surrounding the impact,,, also waves/rings would dispell from the impact semi uniformly.....


so if it wasnt a messy explosion,, but a highly ordered expansion event,, can you compare this event to anything we know of,,,, would it be similar to how a cell uniformly divides itself, you believe it is something like that?

Originally posted by ImaFungi

couldnt it be there was an explosion and then everything was plasma and as it expanded further apart it started forming into how we view the universe today...

That's what the current theory says happened, minus the explosion. An explosion is chaotic and random. The universe is anything but.

so instead of a large explosion how do you think it would have been viewed the begginigs of the universe,, did this expansion happen fast? yet evenly and ordered?

A brief period of rapid inflation. In order to be as even and ordered as things are, the expansion must be very fast.

was it the laws of physics that kept the matter and expansion in order?

Certainly.

i think a random chaotic explosion can eventually lead to order and uniformity down the road.... if i spike a rock into a still lake in a random area, and we watched this event in super slow motion,, there would be a controlled area where drops of water would splash down surrounding the impact,,, also waves/rings would dispell from the impact semi uniformly.....

That's the thing. All the way back to the CMB, the universe has been uniform and isotropic. It didn't eventually become orderly...it has always been that way.

so if it wasnt a messy explosion,, but a highly ordered expansion event,, can you compare this event to anything we know of,,,, would it be similar to how a cell uniformly divides itself, you believe it is something like that?

Nope. About the closest thing we can compare it to is inflating a balloon, with our universe being the rubber around the outside. Except flat. So, maybe if you take a sheet of rubber and you and some friends grab it and stretch it out evenly. That's a decent 2D representation, though it would actually have happened in 3D.

If you start out with a small rubber circle with a pile of sand on it, and you stretch it out, you will get a large circle of rubber with sand spread out evenly on it. This is what happened to the universe. An explosion would never lead to such a uniform spread of matter/energy.

abcnews.go.com...

scientists succeeded in slowing it down to 38 mph

reply to post by CLPrime


what dictated the identity of atoms? how did some atoms end up as part of rock of a plant, and some as a gaseus planet, how did the atoms that make up you and i become belonging to you and i?... is what im trying to ask

if everything expanded orderly and uniformly,,, is there some truth to platos ideas of the realm or eternal existance of shapes and form.... the idea of man and dinasour and insect was made possible and potential at the birth of the big bang,, it was in the blueprints of the big bang that everything that exists could, would and will exist?

Originally posted by artistpoet
reply to post by CLPrime

 

One question I feel I must ask which is not really scientific is this.
- then thought itself is a form of energy or indeed the most highly refined matter.

Since you made this 'not really scientific', I'd like to put my own uninformed opinion on it. lol

Isn't 'thought' the result of energy being used? I am looking at my computer monitor as I write this, and though the monitor is emitting photons that allow my eyes to see the shapes of the letters, it isn't emitting the information within the words. So, my guess is that 'thought' is not a form of energy.

reply to post by jiggerj


Thought is a chemical process. The brain uses glucose to chemically transmit thoughts and other activities between neurons. That burns calories...and calories are energy.