Ask a physicist anything. (8)

[Zippy the Wonderslug]

Hey guys.

Could someone please attempt to explain this atmospheric weirdness?

It was filmed in Brazil yesterday.

SIGNS IN THE HEAVENS: Absolutely Stunning and Phenomenal Ray of Light Across The Skies Over Brazil?! - YouTube

 

[pgp_protector]

Hey guys.

Could someone please attempt to explain this atmospheric weirdness?

It was filmed in Brazil yesterday.

SIGNS IN THE HEAVENS: Absolutely Stunning and Phenomenal Ray of Light Across The Skies Over Brazil?! - YouTube

Light pillar - Wikipedia, the free encyclopedia

 

[Naraoia]

Light pillar - Wikipedia, the free encyclopedia

Looks like it's opposite the sun, though. A very bright anthelion? Or anticrepuscular rays?

Wow. Some interesting things happen with light in our atmosphere!

 

[Zippy the Wonderslug]

Wow Naraoia.

I think you're right.

Thank you.

 

[Zippy the Wonderslug]

I remember watching a special presentation on the television, say maybe 15 years ago or so.

It was all about a single man who was either a physicist, theorist, or a super mathemagician.

Anyway, he somehow found that communication between planets could be instantaneous with this theory he had discovered.

It was based on vibrations or something.

I remember a tuning fork was used as an example.

By hitting a tuning fork, somewhere else something could sense this immediately.

It wasn't based on sound wave air vibrations, hence the possibilities of chatting in real time between planets.

Unfortunately, the rest of the broadcast was about either his disappearance, death or possible murder.

Does this sound remotely familiar with anyone?

If not, what could have been his probable theory in communicating between such long distances instantly?

I would love to revisit this story if possible.

Cheers.

 

[mzungu]

I remember watching a special presentation on the television, say maybe 15 years ago or so.

It was all about a single man who was either a physicist, theorist, or a super mathemagician.

Anyway, he somehow found that communication between planets could be instantaneous with this theory he had discovered.

It was based on vibrations or something.

I remember a tuning fork was used as an example.

By hitting a tuning fork, somewhere else something could sense this immediately.

It wasn't based on sound wave air vibrations, hence the possibilities of chatting in real time between planets.

Unfortunately, the rest of the broadcast was about either his disappearance, death or possible murder.

Does this sound remotely familiar with anyone?

If not, what could have been his probable theory in communicating between such long distances instantly?

I would love to revisit this story if possible.

Cheers.

Alas information cannot exceed the speed of light. Now unless this guy found a way to compress space then I cannot see how he would achieve instant communication.

 

[Elendur]

I remember watching a special presentation on the television, say maybe 15 years ago or so.

It was all about a single man who was either a physicist, theorist, or a super mathemagician.

Anyway, he somehow found that communication between planets could be instantaneous with this theory he had discovered.

It was based on vibrations or something.

I remember a tuning fork was used as an example.

By hitting a tuning fork, somewhere else something could sense this immediately.

It wasn't based on sound wave air vibrations, hence the possibilities of chatting in real time between planets.

Unfortunately, the rest of the broadcast was about either his disappearance, death or possible murder.

Does this sound remotely familiar with anyone?

If not, what could have been his probable theory in communicating between such long distances instantly?

I would love to revisit this story if possible.

Cheers.

This sounds like something from the game series of Mass Effect, quantum entanglement. Unfortunately I'm unable to find better information about it, since I think the only time they mention it is during this clip:

EDI expains what is quantum entanglement communications - YouTube

 

[Zippy the Wonderslug]

Thanks for sharing the video but that really had nothing to do with this guy's theory.

I think it had more to do with some kind of weird, resonance frequency that was never thought of before.

It was a mainstream broadcast on the television when I watched it back then and now it's going to drive me nuts trying to find it again.

 

[Subduction Zone]

This sounds like something from the game series of Mass Effect, quantum entanglement. Unfortunately I'm unable to find better information about it, since I think the only time they mention it is during this clip:

EDI expains what is quantum entanglement communications - YouTube

Of course quantum entanglement cannot be used to send data even in the limited way described in that video. Star Trek is always trying to get around the problem of the ultimate speed limit in the universe.

Here is a simplified approach to explain quantum entanglement. A coin is flipped with a device that provides truly random flips. A picture of each side is taken and placed in two envelopes without anyone seeing either side. The envelopes are given to different people and they separate. It is fairly obvious that until an envelope is opened that either one could have a picture of heads or tails. But once you open it you will instantly know what the other envelope has in it too. And that is true regardless of how far away the other envelope is.

I was looking for more info on QE and found a very similar description in the Wiki article on the subject:

Quantum entanglement - Wikipedia, the free encyclopedia

When you simplify it to the two coin example it does not seem all that weird.

 

[Subduction Zone]

And now one of my favorite physics puzzles.

If you had a globe of uniform density rho ( I can't do a Greek "p"). With the exception of a hollow within the sphere where the density is zero. The hollow is not concentric with the rest of the sphere. Describe the force of gravity throughout the hollow part of the sphere.

Call the radius of the sphere Rs, the radius of the hollow Rh and the vector that describes the distance between the center of the solid and the hollow D.

It should be obvious that the answer I want for the gravity within the hollow must be described using both amount of force and direction.

 

[Elendur]

Thanks for sharing the video but that really had nothing to do with this guy's theory.

I think it had more to do with some kind of weird, resonance frequency that was never thought of before.

It was a mainstream broadcast on the television when I watched it back then and now it's going to drive me nuts trying to find it again.

Oh well, it was worth a shot

 

[Elendur]

Of course quantum entanglement cannot be used to send data even in the limited way described in that video. Star Trek is always trying to get around the problem of the ultimate speed limit in the universe.

Here is a simplified approach to explain quantum entanglement. A coin is flipped with a device that provides truly random flips. A picture of each side is taken and placed in two envelopes without anyone seeing either side. The envelopes are given to different people and they separate. It is fairly obvious that until an envelope is opened that either one could have a picture of heads or tails. But once you open it you will instantly know what the other envelope has in it too. And that is true regardless of how far away the other envelope is.

I was looking for more info on QE and found a very similar description in the Wiki article on the subject:

Quantum entanglement - Wikipedia, the free encyclopedia

When you simplify it to the two coin example it does not seem all that weird.

I had no idea it was 'based' on something real, thanks for the info! (Guess I should've expected it to be, sci-fi usually is)

 

[Subduction Zone]

And now one of my favorite physics puzzles.

If you had a globe of uniform density rho ( I can't do a Greek "p"). With the exception of a hollow within the sphere where the density is zero. The hollow is not concentric with the rest of the sphere. Describe the force of gravity throughout the hollow part of the sphere.

Call the radius of the sphere Rs, the radius of the hollow Rh and the vector that describes the distance between the center of the solid and the hollow D.

It should be obvious that the answer I want for the gravity within the hollow must be described using both amount of force and direction.

I am bumping my physics puzzle along with a clarification. Make sure that you realize D is a distance vector and not a diameter. In fact if anything it is another radius.

 

[Zippy the Wonderslug]

I received this response from another online forum.

I have a vague rememberance of the show of which you speak.
The analogy of the tuning fork caught my attention.
If I am remembering correctly, the theory for the communications was based on generating gravity waves at a set frequency. It was assumed that only the more advanced cultures would recognise these waves and would be capable of responding to them.
The use of quantum entanglement had not, at that time, been widely put forward and would require the use of particles from a single source to be moved from one location to others in order to operate properly. This could take several years before implimentation and would almost defeat the idea of instant communications.

Are there any clues in there that I can use to help me search for this TV episode better?

 

[essentialsaltes]

I am bumping my physics puzzle along with a clarification. Make sure that you realize D is a distance vector and not a diameter. In fact if anything it is another radius.

Gravity is additive, in the sense that the total force of the Earth Moon system on you is the sum of the force from the Earth and the force from the Moon.

If you're inside a solid sphere, the result is well-known - the force points to the center of the sphere, with a magnitude as if a mass equal to all the mass closer to the center than you are were concentrated at the center.

If gravity is additive... it's also subtractive, so the answer would be (I think) the force from the larger sphere treated as whole, minus the force from the hole (treated as if it were a solid). I have not had enough coffee to try to put all the vectors in the right place to get the right radii for calculating the different masses and distances.

Roughly, you'd be mainly attracted to the center of the big sphere, but also repelled from the center of the hole, if you weren't at the center.

[In the limiting case where they are concentric, the 'mass closer to the center than you are' is the same for both spheres, so the two forces cancel out when you subtract them, regardless of your position inside the shell, which is the surprising, but correct, result.]

 

[Subduction Zone]

Yes, you are on your way essentialsaltes.

Don't give up quite yet.

 

[mzungu]

Yes, you are on your way essentialsaltes.

Don't give up quite yet.

At the exact centre of the core of the sphere you will experience zero gravity as all axis will be equally pulling you. If you move off centre then you will experience a stronger gravitational force in that direction and be pulled towards that direction. Now if you were to stand in a hollow sphere situated smack in the core of the larger sphere then basically you will be able to perpetually walk around inside the sphere with your head pointed at the core since your legs would be off centre. It would be like walking on the surface of the sphere but in an inverted one. Me thinks

 

[Subduction Zone]

At the exact centre of the core of the sphere you will experience zero gravity as all axis will be equally pulling you. If you move off centre then you will experience a stronger gravitational force in that direction and be pulled towards that direction. Now if you were to stand in a hollow sphere situated smack in the core of the larger sphere then basically you will be able to perpetually walk around inside the sphere with your head pointed at the core since your legs would be off centre. It would be like walking on the surface of the sphere but in an inverted one. Me thinks

Umm, no. Too early for answers yet. essentialsaltes had the right answer for concentric spheres. If they share the same center the gravity in the hollow is zero.

In this case the center of the two spheres is not concentric.

 

[essentialsaltes]

Yes, you are on your way essentialsaltes.

Wow, that's weird. I thought the vector addition would be nasty, but all sorts of stuff 'cancels out'.

I believe the answer is -4/3πρG D

A constant force directed not toward the center of the sphere, but 'parallel' to the vector connecting the centers of the two spheres.

 

[Subduction Zone]

Wow, that's weird. I thought the vector addition would be nasty, but all sorts of stuff 'cancels out'.

I believe the answer is -4/3πρG D

A constant force directed not toward the center of the sphere, but 'parallel' to the vector connecting the centers of the two spheres.

Yup. You've got it right.

An amazingly neat and clean answer. The diameter of the two spheres is extra information. At first it looks necessary but as you said, it all cancels very nicely.