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What does nothing look like?


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7 minutes ago, vlaiv said:

Where does this energy come from?

isn't this the vacuum energy that is everywhere in the Universe? spontaneous creation and subsequent anihilation of particle/antiparticle pairs results in no net change to the vacuum energy. and it's what allows Hawkings theory that black holes evaporate 

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It seems to me we are all using "nothing" or "nothingness" to mean differt things.

Is it empty space,  a state of consciousness or whatever floats your boat. 

Not only that "looks like" is also being interpreted in different ways.

Linguistic philosophers would be pulling their hair out. Not necessarily a bad thing in my book.

To steal their mantra it depends what you mean by...

No wonder I abandoned philosophy as mostly worthless.

Regards Andrew 

Edited by andrew s
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8 minutes ago, AndrewRrrrrr said:

isn't this the vacuum energy that is everywhere in the Universe? spontaneous creation and subsequent anihilation of particle/antiparticle pairs results in no net change to the vacuum energy. and it's what allows Hawkings theory that black holes evaporate 

Not quite even if one accepts this view on vacum energy. Hawking's radiation creates real particles with the energy for them taken from the gravitational energy of the black hole.

Regards Andrew 

Edited by andrew s
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11 hours ago, Moonshed said:

Hi Jim,

I agree with that comment that some things that are real cannot be seen, I have no problem with that, be it some esoteric mathematical formula or gravity, they are real but cannot be seen.

The problem here is that I have never discussed that point, it arose from a misunderstanding by @vlaiv of my reason why “nothing” can’t be seen, I have never mentioned anything at all about something that cannot be seen, that’s just a misunderstanding and I hope I have now clarified that point.

I am also off to bed now, way past my bedtime.

Cheers

Keith

Cheers Keith, I was really commenting on your reference to Andrew S comment in your previous post 

 “Nothing by definition doesn't look like anything.”

I was trying to be clever by saying well if by definition nothing doesn't look like anything, and anything having a quality, then by extension the look of nothing also has a quality, that being the absence of anything. Exactly what that quality is - I have no idea :) 

Jim 

 

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2 minutes ago, saac said:

Cheers Keith, I was really commenting on your reference to Andrew S comment in your previous post 

 “Nothing by definition doesn't look like anything.”

I was trying to be clever by saying well if by definition nothing doesn't look like anything, and anything having a quality, then by extension the look of nothing also has a quality, that being the absence of anything. Exactly what that quality is - I have no idea :) 

Jim 

 

One must be careful not to mistake the thing for a representation of the thing.

 Nothingness (say empty space) could be represented as awash with quantum fields or a canvas rendered in deepest black. We can in various ways see the representation (mathematical equations or paint) even if not the thing in itself. 

Come on Plato time for you to step up with your forms.

😊 such fun.

Regards Andrew 

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30 minutes ago, vlaiv said:

Where does this energy come from?

I wish i could explain to the extent in the documentary, im trying to wuote a renowned physicist but my knowledge is stretched to its limits. In the film he imagines a cubic space where everything is sucked out, all matter in which we know it, yet matter somehow pops into existence and is immediately destroyed as though energy is being borrowed and paid back. He demonstrates that a space woth trully “nothing” seems to be impossible.

Edited by Sunshine
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1 minute ago, Sunshine said:

I wish i could explain to the extent in the documentary, im trying to wuote a renowned physicist but my knowledge is stretched to its limits.

Just relax and conserve it.😊 Regards Andrew 

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7 minutes ago, andrew s said:

It seems to me we are all using "nothing" or "nothingness" to mean differt things.

Is it empty space,  a state of consciousness or whatever floats your boat. 

Not only that "looks like" is also being interpreted in different was.

Linguistic philosophers would be pulling their hair out. Not necessarily a bad thing in my book.

To steal their mantra it depends what you mean by...

No wonder I abandoned philosophy as mostly worthless.

Regards Andrew 

I think it's fair game to think of nothing in either context - physical or of the mind "consciousness".  Seems to me that a state of nothing cannot exist in our universe which is "physical" after all -  there is no place for it, no means for it to exist.  That leaves it confined to the mind. I'm happy with the notion that it can exist in the mind and in abstract such as mathematics*. As to what it looks like (OP's question), it's one of those things we intuitively know but can only describe it as the absence of anything as you did earlier. 

* The trick of course is not to give "nothing" free reign in the mind :) 

Jim 

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13 minutes ago, AndrewRrrrrr said:

isn't this the vacuum energy that is everywhere in the Universe? spontaneous creation and subsequent anihilation of particle/antiparticle pairs results in no net change to the vacuum energy. and it's what allows Hawkings theory that black holes evaporate 

Ok, so here is a bit of a brain teaser with respect to that.

When we say borrow something - we mean take it with intent of returning it.

We can take it from "parallel universe", "future", or right here "in the space" we are talking about.

Thing is - there is no such thing as negative energy. So we can't borrow it if there is no energy present. I'm not going to entertain notions of borrowing from "parallel universe" and "from the future" (or could we borrow from the past, and if we need to repay it back to the future - that means that in some sense things are deterministic - because what happens if we don't pay it back to the future? :D ). Energy is related to mass - almost equal to mass - one can produce the other and vice verse, and we still have not seen negative mass. That is just one example of how we don't define negative energy. Energy is also by definition "ability to do work", and while I can personally be on a negative side with my ability to do work - same can't be said for particles :D

Let's just talk about borrowing from space itself. This implies that there is a certain pile of energy present in space. There is some sort of energy density in space. Given uncertainty principle for time and energy - we can "borrow" quite a bit of energy in short amount of time. Now if energy density is constant - it means that we must "pull" energy from ever larger volume of space to satisfy our need for peak energy we are borrowing. At some point we run into problem with relativity - we can't "pull" energy fast enough as to respect speed of light for energy transfer. There is limit to how much energy we can borrow given certain energy density.

Now, since this happens to be huge - it turns out that vacuum contains huge energy density. But this is contradictory to relativity - as curvature of space time depends on amount of energy in that space time and if we indeed have huge energy stored in space - we should be able to easily detect curvature of space/time in vacuum. But this is not the case.

So question where this energy comes from is indeed sound one and we still don't have answer to that I think.

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It’s worth subscribing to prime for this one documentary then cancalling it if you chiose, it’s fantastic. In the nothingness, he describes the phenomenon as “fluctuations where pairs of particles and anti particles borrow energy from the vacuum and appear then destroy each other in what seems to be akin to a fizzing” making true nothingness an impossibility. @vlaiv you would love this film, i say film because it is more a film at 2hrs or so.

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8 minutes ago, andrew s said:

One must be careful not to mistake the thing for a representation of the thing.

 Nothingness (say empty space) could be represented as awash with quantum fields or a canvas rendered in deepest black. We can in various ways see the representation (mathematical equations or paint) even if not the thing in itself. 

Come on Plato time for you to step up with your forms.

😊 such fun.

Regards Andrew 

In that sense the devil really is in the definition - back to the OP, - "what do you mean by nothing".  

Jim 

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6 minutes ago, Sunshine said:

I wish i could explain to the extent in the documentary, im trying to wuote a renowned physicist but my knowledge is stretched to its limits. In the film he imagines a cubic space where everything is sucked out, all matter in which we know it, yet matter somehow pops into existence and is immediately destroyed as though energy is being borrowed and paid back. He demonstrates that a space woth trully “nothing” seems to be impossible.

Yes, that is why we have mayonnaise.

I'm serious :D.

There is an effect that is explained by this called Casimir effect (https://en.wikipedia.org/wiki/Casimir_effect)

In order to understand this effect - we must use virtual particles popping in and out of existence.

It turns out that this effect is responsible for Mayo not behaving like liquid and keeping its shape.

 

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11 hours ago, Sunshine said:

If you have Amazon prime I highly recommend this documentary by well known physicist  Jim Al-Khalili, it is a riveting documentary about the science of empty space. It is called “everything and nothing” a wonderful watch if you have prime, and if you dont have Prime, it’s worth seeking out on some other platform, the question you pose in this thread is explored in great detail.

Definitely, very watchable and one of the best from Prof Alkhalili. 

Jim 

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48 minutes ago, vlaiv said:

Where does this energy come from?

I always thought of it as a an aggregation of the fluctuations in the quantum field. All pervasive throughout the fabric of the universe. 

Jim 

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16 minutes ago, vlaiv said:

Yes, that is why we have mayonnaise.

I'm serious :D.

There is an effect that is explained by this called Casimir effect (https://en.wikipedia.org/wiki/Casimir_effect)

In order to understand this effect - we must use virtual particles popping in and out of existence.

It turns out that this effect is responsible for Mayo not behaving like liquid and keeping its shape.

 

This is still a much debated topic. It can be explained perfectly well by other models. For example van der Waals forces. 

See her for an example 

https://www.physicsforums.com/threads/jaffes-take-on-casimir-force.68169/

Regards Andrew 

Edited by andrew s
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Here's a question for those who are better informed.  With respect to fields - electromagnetic field, gravitational fields etc.  Are these fields present throughout space or could there be regions (or time) where they are absent?  My common thinking is that they are present throughout, part of the fabric of the universe. 

Jim 

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Anything that can be described can't be "nothing".

I spent a lot of time, as a boy, thinking about why and from what preconditions do we exist.

Primarily I was concerned about what would be if there was no Universe. That was the nothingness I still think about today. The complete absence of anything that can "be".

Plainly, the Universe didn't spring into existence from that kind of "nothing" so nothing is a state that can't have ever existed?

 

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7 minutes ago, saac said:

Here's a question for those who are better informed.  With respect to fields - electromagnetic field, gravitational fields etc.  Are these fields present throughout space or could there be regions (or time) where they are absent?  My common thinking is that they are present throughout, part of the fabric of the universe. 

Jim 

Yes, in quantum field theories QFT they extend throughout all space and time. In these theories there are creation and annihilation operators that add or remove excitations.

Once all excitations have been removed you can go no further and get the vaccum state. 

GR is somewhat different as it a classical theory defined on all of spacetime. But yes is the short answer.

Regards Andrew 

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A lot of modern physics sounds like nonsense, it has to be said.

 

Virtual this, imaginary that, negative energy etc. I know this fits the observations, but my guess is somebody is having a right laugh here.

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40 minutes ago, 900SL said:

A lot of modern physics sounds like nonsense, it has to be said.

 

Virtual this, imaginary that, negative energy etc. I know this fits the observations, but my guess is somebody is having a right laugh here.

That's because like me you are an engineer and as we know engineers are too short to see over the fence like physicists who are of course taller. :) 

Jim 

Edited by saac
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12 hours ago, Sunshine said:

If you have Amazon prime I highly recommend this documentary by well known physicist  Jim Al-Khalili, it is a riveting documentary about the science of empty space. It is called “everything and nothing” a wonderful watch if you have prime, and if you dont have Prime, it’s worth seeking out on some other platform, the question you pose in this thread is explored in great detail.

Agree 100%. Well worth watching.

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57 minutes ago, saac said:

Here's a question for those who are better informed.  With respect to fields - electromagnetic field, gravitational fields etc.  Are these fields present throughout space or could there be regions (or time) where they are absent?  My common thinking is that they are present throughout, part of the fabric of the universe. 

Jim 

Hi Jim,

I would agree with you in that all fields are an intrinsic part of the fabric of the universe. I can only think of one place where they may not exist, inside a black hole.

Cheers

Keith

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12 hours ago, VNA said:

Hello, here is the answer--I think?

 

 

A very good talk by Lawrence Krauss sprinkled as usual with his little quips, he has a wicked sense of humour. For those intending to watch this very good presentation be advised that Krauss does not enter the stage until 13 minutes in and starts talking about Nothing at 35 minutes in. Well worth watching all of it though, after he first appears.

Cheers

Keith

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