What are mass and energy?

How does science work? And what's all this about quantum mechanics?

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uwot
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What are mass and energy?

Post by uwot » Fri Feb 24, 2017 8:39 pm


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HexHammer
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Re: What are mass and energy?

Post by HexHammer » Sat Feb 25, 2017 1:39 am

Basic info made weird. Lacks Einsteins E=MC2.

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Greta
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Re: What are mass and energy?

Post by Greta » Sat Feb 25, 2017 3:28 am

Excellent. Presented in an original and thought-provoking way.

A question. Given the effect of rapid spin and the importance in the energy of an entity, do you think Schwartzchild (spinless) black holes are real or purely theoretical? Surely when a star supernovas the push of gravity inwards would hugely increase its spin ...?

I visualise a black hole's centre basically as an incredibly tiny and intense little thing spinning at insane speeds and exerting complex, vicious forces all around it, I suppose something like an exaggerated version of a neutron star in all respects.

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Cerveny
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Re: What are mass and energy?

Post by Cerveny » Sat Feb 25, 2017 2:17 pm

You can see the energy as a some kind of "pressure/tension" in spacetime along the time axis. When such pressure exceeds critical value, it can cause structural defect of regular structure of physical space - the creation of pair of elementary particles. Generally such "pressure" affects the configuration of the next/following condensation planck time layer - common development of physical system...

uwot
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Re: What are mass and energy?

Post by uwot » Sat Feb 25, 2017 2:48 pm

Greta wrote:Excellent. Presented in an original and thought-provoking way.
Thank you.
Greta wrote:A question. Given the effect of rapid spin and the importance in the energy of an entity, do you think Schwartzchild (spinless) black holes are real or purely theoretical?
Schwarzschild black holes are based on solutions to Einstein's field equations. In that sense, they are mathematical entities. As such, they don't have to correspond to anything physical, nor is there any compulsion to explain how they work. If you think about string theory, for example, the idea is that there are these strings that have been vibrating for 13.78 billion years, without any explanation of what keeps plucking them. General relativity itself is based on the idea that matter warps spacetime, but there is no account of the mechanism it uses to do so. Nonetheless, GR is supported by a ton of evidence, while string theory is still waiting. It's an ontological conundrum: can the fact that something exists in mathematics mean it can exist in the physical world without having any properties that we would normally describe as physical? Yer pays yer money, and takes yer choice. Nah mate, is my best guess.
So far as I know, the only direct evidence that any black holes exist is the gravitational waves detected by LIGO, but it is not currently possible to tell whether the cause was actually black holes colliding, much less whether they were spinning. Data from the Event Horizon Telescope will hopefully be a bit more informative.
Greta wrote:Surely when a star supernovas the push of gravity inwards would hugely increase its spin ...?
I think that is almost certainly the case. My hunch is that all black holes are rotating, because that at least suggests a mechanism.
Greta wrote:I visualise a black hole's centre basically as an incredibly tiny and intense little thing spinning at insane speeds and exerting complex, vicious forces all around it, I suppose something like an exaggerated version of a neutron star in all respects.
Well, the singularity is a mathematical object in that it is the place were density becomes infinite. I'm not sure what infinite density would mean for a physical object, but yes, that's pretty much how I imagine black holes too.

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Greta
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Re: What are mass and energy?

Post by Greta » Sat Feb 25, 2017 11:11 pm

uwot wrote:Nah mate, is my best guess.
... Well, the singularity is a mathematical object in that it is the place were density becomes infinite. I'm not sure what infinite density would mean for a physical object, but yes, that's pretty much how I imagine black holes too.
Oh good, I was hoping that I wasn't flying off beam. Yes, these mathematical theoretical entities - especially mad things like singularities - seem unlikely, although there may be entities that are (more likely were) almost singularities.

It's interesting to think of cosmic objects without their classifications as there is an increasingly a clear continuum and cosmic hierarchy:

Black holes - supermassive, stellar, rare intermediate
Between black holes and stars - dense degenerate stars - neutron stars and white dwarfs
Stars - from blue giants to red dwarfs
Between planets and stars - brown dwarfs
Gas giants
Between gas giants and rocky planets - Ice giants/gas dwarfs
Rocky spherical bodies - planets, dwarf planets and moons
Amorphously shaped comets and asteroids.

They are all effectively the same object thing, barring mass, gravity and time. Also, it seems that the most complex and interesting things happen "in the middle< away from extremities - the habitable zone, planetary size, star size, galactic habitable zones, and I suspect that galactic size and zones of galactic clusters are more habitable than others, with "sweet spots" and "no go zones".

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Noax
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Re: What are mass and energy?

Post by Noax » Sun Feb 26, 2017 12:37 am

uwot wrote:Here's the latest http://willijbouwman.blogspot.co.uk
Some nits:

How much damage is done by mass X is not a function of its compactness. It doesn't directly follow.
A 1kg sponge if as rigid as the brick would have done equivalent damage to stickman.
Getting hit with the corner of the rigid sponge (more pressure) would have done more damage than being hit with the flat of the brick.

A UV photon has more mass (energy) than an IR one. Its shorter wavelength is not a measure of its compactness, since they don't really have a volume.

I quizzed my kids at the table: How fast must a ping-pong ball be thrown to earth to have it penetrate to the other side? The math was unimportant. Point was that if you say it can't be done, you're just not envisioning throwing it hard enough.

uwot
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Re: What are mass and energy?

Post by uwot » Sun Feb 26, 2017 3:59 pm

Noax wrote:
uwot wrote:Here's the latest http://willijbouwman.blogspot.co.uk
Some nits:

How much damage is done by mass X is not a function of its compactness. It doesn't directly follow.
A 1kg sponge if as rigid as the brick would have done equivalent damage to stickman.
Getting hit with the corner of the rigid sponge (more pressure) would have done more damage than being hit with the flat of the brick.
Indeed. The key word is pressure, after all, if the mass was in the form of a javelin, Stickman would almost certainly be dead. I will make that point clearer in the final draft.
Noax wrote:A UV photon has more mass (energy) than an IR one. Its shorter wavelength is not a measure of its compactness, since they don't really have a volume.
Creating an image for a photon is tricky, since ideally it should be able to account for the wave and particle properties they display. I take your point, but can't think of a better way to illustrate something that even the best physicists don't fully understand.
Noax wrote:I quizzed my kids at the table: How fast must a ping-pong ball be thrown to earth to have it penetrate to the other side? The math was unimportant. Point was that if you say it can't be done, you're just not envisioning throwing it hard enough.
Well, there is a limit to how hard you can throw anything, of course. Even at close to c, while a ping-pong ball would make an impressive crater, I don't think it would come out the other side intact.
Thank you; they're all valid points, clarifying which will help improve the final draft.

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Arising_uk
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Re: What are mass and energy?

Post by Arising_uk » Sun Feb 26, 2017 4:10 pm

HexHammer wrote:Basic info made weird. Lacks Einsteins E=MC2.
:lol: And you'd understand Einstein would you.

Basic Physics made simple, it's called a sound pedagogy.

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Noax
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Re: What are mass and energy?

Post by Noax » Sun Feb 26, 2017 7:47 pm

uwot wrote:
Noax wrote:A UV photon has more mass (energy) than an IR one. Its shorter wavelength is not a measure of its compactness, since they don't really have a volume.
Creating an image for a photon is tricky, since ideally it should be able to account for the wave and particle properties they display. I take your point, but can't think of a better way to illustrate something that even the best physicists don't fully understand.
I actually really like the image. The text was what I didn't like, implying that they had the same mass (they don't) and it was a difference in density, which is meaningless for a thing without volume.
One other wording in need of change is using 'mass' where it says 'weight'. Mass is energy/inertia, and weight is a measure of force. Easy to forget that since most scales that measure weight incorrectly report it in units of mass. I personally like to keep a mass-scale in my house in favor of one that measures weight. The latter never seem to give consistent readouts
.
Well, there is a limit to how hard you can throw anything, of course. Even at close to c, while a ping-pong ball would make an impressive crater, I don't think it would come out the other side intact.
Intact? It doesn't even begin to graze the atmosphere before it is vaporized. I had two methods of deciding if one had achieved the act: 1) At least one ping pong ball worth of mass must be ejected from the far side of Earth. 2 ) Much more energy: At least 1% of the original material of the ball must eject to the far side. Not sure if this can be done since the identity of matter is not really defined when discussing particle interactions like that.

No, there is no limit to how hard you can throw it. One can always add more energy, which has no upper limit. I don't know enough about distribution of shock waves to assess how much the earth would survive either hit. Both would likely extinguish all life.

PS: You have a real talent with the artwork. Quite professional. I've had plenty of school texts illustrated far worse than what you're putting out.

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Harbal
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Re: What are mass and energy?

Post by Harbal » Sun Feb 26, 2017 9:44 pm

Mass is what fat people have an abundance of, energy is what they have a deficiency of.

uwot
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Re: What are mass and energy?

Post by uwot » Mon Feb 27, 2017 12:39 am

Noax wrote:I actually really like the image. The text was what I didn't like, implying that they had the same mass (they don't) and it was a difference in density, which is meaningless for a thing without volume.
One other wording in need of change is using 'mass' where it says 'weight'. Mass is energy/inertia, and weight is a measure of force.
Objections noted. Yes, there will need to be some editing done.
Noax wrote:PS: You have a real talent with the artwork. Quite professional. I've had plenty of school texts illustrated far worse than what you're putting out.
Thank you.

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Re: What are mass and energy?

Post by wtf » Mon Feb 27, 2017 1:07 am

Harbal wrote:Mass is what fat people have an abundance of, energy is what they have a deficiency of.
So fat people are more (gravitationally) attractive?

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HexHammer
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Re: What are mass and energy?

Post by HexHammer » Mon Feb 27, 2017 2:10 am

Arising_uk wrote:
HexHammer wrote:Basic info made weird. Lacks Einsteins E=MC2.
:lol: And you'd understand Einstein would you.

Basic Physics made simple, it's called a sound pedagogy.
As usual you have no clue what you are saying.
"If you can't explain it simply, you don't understand it well enough." - Albert Einstein
..so yes I do understand what Einstein said. Most people learn, but u'll never learn.

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Arising_uk
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Re: What are mass and energy?

Post by Arising_uk » Mon Feb 27, 2017 3:42 am

HexHammer wrote:...
..so yes I do understand what Einstein said. Most people learn, but u'll never learn.
Do you? Well given that only a few physicists understand what he said I won't take your word for it.

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