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Entanglement Builds Space-Time. Now "Magic" Gives It Gravity

quantamagazine.org

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Re: Entanglement Builds Space-Time. Now "Magic" Gives It Gravity

#101

Post by dwroberts »

zchrykng wrote: post #61
dwroberts wrote: post #12

Earlier quoted context omitted.

> this whole field is starting to feel more like a jobs program for mathematicians out of new ideas. So sick of seeing phrases like this. Science is not business. It is not about producing results that you personally think are important. It is understanding the nature of the universe for the sake of it.

Please enlighten us how purely theoretical mathematical constructs, that are impossible to test, help us understand anything about our universe.

Lots of science is impossible to test practically for hundreds of years before it is actually experimentally verified

Re: Entanglement Builds Space-Time. Now "Magic" Gives It Gravity

#102

Post by TACIXAT »

lubujackson wrote: post #92
AnimalMuppet wrote: post #69

Earlier quoted context omitted.

Could you be more specific? How does bending time cause the Earth to orbit the Sun?

Imagine you are driving in a car coming up parallel to the sun on your left. Time moves a bit faster for you on the left side than the right side. This slight speedup makes your left side traverse space faster than the right side, which causes a slight drift to the left (and also makes you spin). Now just add massive scale and distances.

That's a very cool analogy but I might not be understanding something here. Why then do objects that have no light have gravity? If 99% comes from time dilation, why am I stuck to the earth rather than drifting toward light sources?

Re: Entanglement Builds Space-Time. Now "Magic" Gives It Gravity

#103

Post by AnimalMuppet »

lubujackson wrote: post #92
AnimalMuppet wrote: post #69

Earlier quoted context omitted.

Could you be more specific? How does bending time cause the Earth to orbit the Sun?

Imagine you are driving in a car coming up parallel to the sun on your left. Time moves a bit faster for you on the left side than the right side. This slight speedup makes your left side traverse space faster than the right side, which causes a slight drift to the left (and also makes you spin). Now just add massive scale and distances.

One nit: Time moves a bit slower on the sun's side.

Other than that, thank you for a very clear explanation.

Re: Entanglement Builds Space-Time. Now "Magic" Gives It Gravity

#104

Post by mixmastamyk »

nilkn wrote: post #88
bgilroy26 wrote: post #84

Earlier quoted context omitted.

Does the atmosphere stay attached to the earth due to the bending of time?

That's right -- the atmosphere stays attached to the Earth mostly thanks to gravity, and the Earth's gravity in GR is almost entirely the gradient in clock rate near the Earth. Near Earth’s surface, clocks lower down tick very slightly slower than clocks higher up. The change in tick rate is on the order of 10^(-16) per meter. While extremely small, that's enough to generate the familiar 9.8 m/s^2 spatial acceleratio…

I’ve seen this described before in terms of how GPS is able to do what it does, so not surprising. But still haven’t explained why time would so dominate the space dimension.

Edit: The response below is dead for some reason, please vouch.

Re: Entanglement Builds Space-Time. Now "Magic" Gives It Gravity

#105

Post by sigmoid10 »

vbezhenar wrote: post #25
sigmoid10 wrote: post #3

>In holographic theories, physicists may have traced the pliability of space-time to its quantum roots ...ah yes holography again. Not to say that all these insights from it are completely worthless, but unless we actually find a holographic dual of our universe instead of AdS spaces (which are the opposite of our universe if anything), this whole field is starting to feel more like a jobs program for mathematicians…

That's how science always worked. The stupid people throw money at smart people and sometimes they pay back with good things. Any attempts to optimize that is futile, so the best we can do is to continue throwing money.

Unfortunately that is not how it works in capitalist societies, because the smart people will eventually figure out how to siphon the maximum amount of money out of the government regardless of the results. Or do you think we should also keep throwing money at Boeing because there are still a few smart engineers left and we might get a worthwhile Starliner and SLS eventually it we just keep throwing money?

Re: Entanglement Builds Space-Time. Now "Magic" Gives It Gravity

#106

Post by sigmoid10 »

zmgsabst wrote: post #27
sigmoid10 wrote: post #3

>In holographic theories, physicists may have traced the pliability of space-time to its quantum roots ...ah yes holography again. Not to say that all these insights from it are completely worthless, but unless we actually find a holographic dual of our universe instead of AdS spaces (which are the opposite of our universe if anything), this whole field is starting to feel more like a jobs program for mathematicians…

Also, if all you have is a dual model, then it’s equally accurate to say entanglement arises from spacetime. Eg, this article describes entanglement giving rise to wormholes, but the model equally says wormholes give rise to entanglement. They’re promoting their preferred frame to ontological status when you can’t use a dual model to assert more than equivalence between frames.

Welcome to modern theoretical physics. This stuff has been going on for more than a quarter of a century now. Yes, AdS/CFT was super cool when it first came out. Just like String Theory was. But both have produced nothing that people had originally hoped for. Just endless mathematical intricacies that are further and further removed from our real universe. The best that came out was some mathematical tooling for adjacent fields that had little to do with understanding the fundamental rules of the universe.

Re: Entanglement Builds Space-Time. Now "Magic" Gives It Gravity

#107

Post by simiones »

TACIXAT wrote: post #102
lubujackson wrote: post #92

Earlier quoted context omitted.

Imagine you are driving in a car coming up parallel to the sun on your left. Time moves a bit faster for you on the left side than the right side. This slight speedup makes your left side traverse space faster than the right side, which causes a slight drift to the left (and also makes you spin). Now just add massive scale and distances.

That's a very cool analogy but I might not be understanding something here. Why then do objects that have no light have gravity? If 99% comes from time dilation, why am I stuck to the earth rather than drifting toward light sources?

Light has nothing to do with this.

The point is that mass bends space-time. The amount of bending is dependent on the size of the mass and on the distance from the mass. Even though the Sun is incomparably heavier than the Earth, it is also MUCH farther away from you. So, space-time around the Earth is curved much more towards the center of the Earth than it is towards the center of the Sun. In the mattress analogy, consider a large mattress, with a bowling ball and a car sitting on it. The car will obviously bend the mattress much more, but if you're close to the bowling ball, you'll still fall towards the bowling ball first before both you and it fall towards the car.

So, say you're in an airplane moving directly forward, with the Sun just overhead (and the Earth obviously just below you). The Earth curves spacetime towards it a lot in this area, while the Sun curves it towards itself just a little bit. The overall curvature is such that time still moves more for the bottom of the plane (closer to the Earth) than the top of the plane (closer to the Sun). So, the bottom side moves a little slower than the top side, but the structural integrity of the plane pulls the top side towards the bottom, causing a slight motion towards the Earth - gravity [note that the GP's explanation got the signs a little wrong - time flows slower, not faster, closer to a big mass]. Conversely, if the Earth disappears from the picture and only the Sun remains, now the top part of the plane will move slightly slower, pulling the bottom part towards it, and thus towards the Sun.

Re: Entanglement Builds Space-Time. Now "Magic" Gives It Gravity

#108

Post by sigmoid10 »

Erem wrote: post #65
zchrykng wrote: post #61

Earlier quoted context omitted.

Please enlighten us how purely theoretical mathematical constructs, that are impossible to test, help us understand anything about our universe.

Imaginary numbers are purely theoretical, but they turn out very helpful in almost every engineering discipline

Imaginary numbers are a helpful tool for calculating things in our universe. All these holographic theories and their insights are based on a universe that behaves basically opposite to ours.

Re: Entanglement Builds Space-Time. Now "Magic" Gives It Gravity

#109

Post by nilkn »

mixmastamyk wrote: post #104
nilkn wrote: post #88

Earlier quoted context omitted.

That's right -- the atmosphere stays attached to the Earth mostly thanks to gravity, and the Earth's gravity in GR is almost entirely the gradient in clock rate near the Earth. Near Earth’s surface, clocks lower down tick very slightly slower than clocks higher up. The change in tick rate is on the order of 10^(-16) per meter. While extremely small, that's enough to generate the familiar 9.8 m/s^2 spatial acceleratio…

I’ve seen this described before in terms of how GPS is able to do what it does, so not surprising. But still haven’t explained why time would so dominate the space dimension. Edit: The response below is dead for some reason, please vouch.

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