If you had a giant cutting disc 60 miles diameter and rotated it 1000 rps, would the edge be traveling faster than light?
If you had a giant cutting disc 60 miles diameter and rotated it 1000 rps, would the edge be traveling faster than light?
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If you had a giant cutting disc 60 miles diameter and rotated it 1000 rps, would the edge be traveling faster than light?
$begingroup$
As if there was a giant angle-grinder in space that slowly increased its speed. The question assumes that material exists to make this super-disk that doesn't rip apart. What happens as the edges approach light-speed and if it can't, where would the resistance be felt? Could the angle-grinder not produce the torque?
Trying to envisage a giant, planet slicing machine. Perhaps the disc could be a lot wider and rotate more slowly.
space time-travel faster-than-light macroengineering
asked 9 hours ago
Philip ThomasPhilip Thomas
16426
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Philip Thomas is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
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add a comment |
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As if there was a giant angle-grinder in space that slowly increased its speed. The question assumes that material exists to make this super-disk that doesn't rip apart. What happens as the edges approach light-speed and if it can't, where would the resistance be felt? Could the angle-grinder not produce the torque?
Trying to envisage a giant, planet slicing machine. Perhaps the disc could be a lot wider and rotate more slowly.
space time-travel faster-than-light macroengineering
asked 9 hours ago
Philip ThomasPhilip Thomas
16426
New contributor
Philip Thomas is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
$endgroup$
$begingroup$
Downvotes without comment are unhelpful and unproductive.
$endgroup$
– Starfish Prime
9 hours ago
$begingroup$
This seems like a question better suited for another site, but suffice to say: relativity will probably give you all the answers you need. Lack of torque isn't precisely the problem you face, but relativistic mass gain certainly won't help.
$endgroup$
– Starfish Prime
9 hours ago
4
$begingroup$
On physics.stackexchange: Rotate a long bar in space and get close to (or even beyond) the speed of light 𝑐
$endgroup$
– Alexander
8 hours ago
$begingroup$
@StarfishPrime Yes. I'm beginning to see that the physics for mass gain is the same whether for rotation or linear. It wasn't obvious to me at first.
$endgroup$
– Philip Thomas
8 hours ago
add a comment |
$begingroup$
As if there was a giant angle-grinder in space that slowly increased its speed. The question assumes that material exists to make this super-disk that doesn't rip apart. What happens as the edges approach light-speed and if it can't, where would the resistance be felt? Could the angle-grinder not produce the torque?
Trying to envisage a giant, planet slicing machine. Perhaps the disc could be a lot wider and rotate more slowly.
space time-travel faster-than-light macroengineering
asked 9 hours ago
Philip ThomasPhilip Thomas
16426
New contributor
Philip Thomas is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
$endgroup$
As if there was a giant angle-grinder in space that slowly increased its speed. The question assumes that material exists to make this super-disk that doesn't rip apart. What happens as the edges approach light-speed and if it can't, where would the resistance be felt? Could the angle-grinder not produce the torque?
Trying to envisage a giant, planet slicing machine. Perhaps the disc could be a lot wider and rotate more slowly.
space time-travel faster-than-light macroengineering
space time-travel faster-than-light macroengineering
asked 9 hours ago
Philip ThomasPhilip Thomas
16426
New contributor
Philip Thomas is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
asked 9 hours ago
Philip ThomasPhilip Thomas
16426
New contributor
Philip Thomas is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
edited 8 hours ago
Philip Thomas
asked 9 hours ago
Philip ThomasPhilip Thomas
16426
New contributor
Philip Thomas is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
asked 9 hours ago
Philip ThomasPhilip Thomas
16426
asked 9 hours ago
Philip ThomasPhilip Thomas
16426
16426
New contributor
Philip Thomas is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
New contributor
Philip Thomas is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
$begingroup$
Downvotes without comment are unhelpful and unproductive.
$endgroup$
– Starfish Prime
9 hours ago
$begingroup$
This seems like a question better suited for another site, but suffice to say: relativity will probably give you all the answers you need. Lack of torque isn't precisely the problem you face, but relativistic mass gain certainly won't help.
$endgroup$
– Starfish Prime
9 hours ago
4
$begingroup$
On physics.stackexchange: Rotate a long bar in space and get close to (or even beyond) the speed of light 𝑐
$endgroup$
– Alexander
8 hours ago
$begingroup$
@StarfishPrime Yes. I'm beginning to see that the physics for mass gain is the same whether for rotation or linear. It wasn't obvious to me at first.
$endgroup$
– Philip Thomas
8 hours ago
add a comment |
$begingroup$
Downvotes without comment are unhelpful and unproductive.
$endgroup$
– Starfish Prime
9 hours ago
$begingroup$
This seems like a question better suited for another site, but suffice to say: relativity will probably give you all the answers you need. Lack of torque isn't precisely the problem you face, but relativistic mass gain certainly won't help.
$endgroup$
– Starfish Prime
9 hours ago
4
$begingroup$
On physics.stackexchange: Rotate a long bar in space and get close to (or even beyond) the speed of light 𝑐
$endgroup$
– Alexander
8 hours ago
$begingroup$
@StarfishPrime Yes. I'm beginning to see that the physics for mass gain is the same whether for rotation or linear. It wasn't obvious to me at first.
$endgroup$
– Philip Thomas
8 hours ago
$begingroup$
Downvotes without comment are unhelpful and unproductive.
$endgroup$
– Starfish Prime
9 hours ago
$begingroup$
Downvotes without comment are unhelpful and unproductive.
$endgroup$
– Starfish Prime
9 hours ago
$begingroup$
This seems like a question better suited for another site, but suffice to say: relativity will probably give you all the answers you need. Lack of torque isn't precisely the problem you face, but relativistic mass gain certainly won't help.
$endgroup$
– Starfish Prime
9 hours ago
$begingroup$
This seems like a question better suited for another site, but suffice to say: relativity will probably give you all the answers you need. Lack of torque isn't precisely the problem you face, but relativistic mass gain certainly won't help.
$endgroup$
– Starfish Prime
9 hours ago
4
4
$begingroup$
On physics.stackexchange: Rotate a long bar in space and get close to (or even beyond) the speed of light 𝑐
$endgroup$
– Alexander
8 hours ago
$begingroup$
On physics.stackexchange: Rotate a long bar in space and get close to (or even beyond) the speed of light 𝑐
$endgroup$
– Alexander
8 hours ago
$begingroup$
@StarfishPrime Yes. I'm beginning to see that the physics for mass gain is the same whether for rotation or linear. It wasn't obvious to me at first.
$endgroup$
– Philip Thomas
8 hours ago
$begingroup$
@StarfishPrime Yes. I'm beginning to see that the physics for mass gain is the same whether for rotation or linear. It wasn't obvious to me at first.
$endgroup$
– Philip Thomas
8 hours ago
add a comment |
3 Answers
3
active
oldest
votes
$begingroup$
I won't dare sticking my finger into the relativistic theory of rotating bodies, I will just go with the approximation of linear motion, which is valid for infinitesimal rotations.
We know that, by relativity, the mass of an object moving at velocity v is increased according to Lorentz factor $gamma=$$1 over sqrt1-v^2/c^2$.
Therefore, the more the tangential velocity of the disc increases, the more its mass increases, the more becomes difficult to increase its velocity. Moreover, being a rotating body, we also need to take into account the increase in centripetal force, which would sooner or later overcome the resistance of the material.
My guess is that the disc will break way before any relativistic effect can be sensed (ask any turbine manufacturer).
answered 8 hours ago
L.Dutch♦L.Dutch
97.9k31230473
$endgroup$
4
$begingroup$
I've a sneaking suspicion that any material with infinite tensile strength is itself a violation of relativity (in the same way that a magical incompressible rod is). I'm not sure how the untearable disc causes physics to break... maybe you get Weirdness when you try to feed it into a black hole, so the OP is probably doubly out of luck.
$endgroup$
– Starfish Prime
8 hours ago
5
$begingroup$
@StarfishPrime yeah it would take an infinite amount of bonding energy to have infinite tensile strength. Energy=mass so the object would have infinite mass. So the universe would collapse in on it long before we are at infinite
$endgroup$
– Andrey
7 hours ago
$begingroup$
@Andrey ta, that's a nice, straightforward explanation. I'll remember that for future use!
$endgroup$
– Starfish Prime
7 hours ago
add a comment |
$begingroup$
I was once where you are.
I wondered if it was possible to create a rotating mirrored propeller capable of spinning fast enough to separate particle pairs in the quantum foam in a manner reminiscent of a Quantum Vacuum plasma thruster.
The answer is no. The reason is material stress.
Basically the maximum stress on a rotating solid disc (or arm) scales as the square of both disc radius and orbital velocity. This means that long before the edge of your disc is moving anywhere near C the disc itself is being put under stresses usually reserved for... erm... supernovae? Possibly freshly expanding galaxies.
Either way: it was a while back when I ran the numbers, but suffice it to say that your disc will have broken apart looong before you get up to these kinds of speeds.
answered 7 hours ago
Joe BloggsJoe Bloggs
38k20106190
$endgroup$
add a comment |
$begingroup$
Millisecond pulsars! Gravity waves! Imperial to metric conversions!
60 mile diameter disc.
188 mile circumference.
1000 rotations per second = 188 * 1000 miles / second = 188,000 miles/second
Speed of light = 299 792 458 m / s = 186282 miles / second.
The edge would be going faster than the speed of light; not allowed.
Here is a fine and relevant answer lifted from the astronomy stack, which asks about neutron stars. The one is question rotates at 25% of the speed of light. Go visit and upvote!
https://astronomy.stackexchange.com/questions/1291/what-is-the-fastest-spinning-rotation-of-a-neutron-star
The answer cites this wikipedia article
https://en.wikipedia.org/wiki/Millisecond_pulsar
with this text
Current theories of neutron star structure and evolution predict that
pulsars would break apart if they spun at a rate of c. 1500 rotations
per second or more, and that at a rate of above about 1000
rotations per second they would lose energy by gravitational radiation
faster than the accretion process would speed them up.
The cool thing for me here "lose energy by gravitational radiation". Huh?? I knew about gravity waves but did not realize that the production of gravity waves would allow a thing to slough energy! https://en.wikipedia.org/wiki/Gravitational_wave
There is the solution for how dark matter sheds accumulated energy on descending into a gravity well - as gravity waves!
OK; the saw blade. It will need to go slower. But you can make it out of a handy millisecond pulsar and still have it go plenty fast.
answered 3 hours ago
WillkWillk
125k29232518
$endgroup$
add a comment |
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3 Answers
3
active
oldest
votes
3 Answers
3
active
oldest
votes
active
oldest
votes
active
oldest
votes
$begingroup$
I won't dare sticking my finger into the relativistic theory of rotating bodies, I will just go with the approximation of linear motion, which is valid for infinitesimal rotations.
We know that, by relativity, the mass of an object moving at velocity v is increased according to Lorentz factor $gamma=$$1 over sqrt1-v^2/c^2$.
Therefore, the more the tangential velocity of the disc increases, the more its mass increases, the more becomes difficult to increase its velocity. Moreover, being a rotating body, we also need to take into account the increase in centripetal force, which would sooner or later overcome the resistance of the material.
My guess is that the disc will break way before any relativistic effect can be sensed (ask any turbine manufacturer).
answered 8 hours ago
L.Dutch♦L.Dutch
97.9k31230473
$endgroup$
4
$begingroup$
I've a sneaking suspicion that any material with infinite tensile strength is itself a violation of relativity (in the same way that a magical incompressible rod is). I'm not sure how the untearable disc causes physics to break... maybe you get Weirdness when you try to feed it into a black hole, so the OP is probably doubly out of luck.
$endgroup$
– Starfish Prime
8 hours ago
5
$begingroup$
@StarfishPrime yeah it would take an infinite amount of bonding energy to have infinite tensile strength. Energy=mass so the object would have infinite mass. So the universe would collapse in on it long before we are at infinite
$endgroup$
– Andrey
7 hours ago
$begingroup$
@Andrey ta, that's a nice, straightforward explanation. I'll remember that for future use!
$endgroup$
– Starfish Prime
7 hours ago
add a comment |
$begingroup$
I won't dare sticking my finger into the relativistic theory of rotating bodies, I will just go with the approximation of linear motion, which is valid for infinitesimal rotations.
We know that, by relativity, the mass of an object moving at velocity v is increased according to Lorentz factor $gamma=$$1 over sqrt1-v^2/c^2$.
Therefore, the more the tangential velocity of the disc increases, the more its mass increases, the more becomes difficult to increase its velocity. Moreover, being a rotating body, we also need to take into account the increase in centripetal force, which would sooner or later overcome the resistance of the material.
My guess is that the disc will break way before any relativistic effect can be sensed (ask any turbine manufacturer).
answered 8 hours ago
L.Dutch♦L.Dutch
97.9k31230473
$endgroup$
4
$begingroup$
I've a sneaking suspicion that any material with infinite tensile strength is itself a violation of relativity (in the same way that a magical incompressible rod is). I'm not sure how the untearable disc causes physics to break... maybe you get Weirdness when you try to feed it into a black hole, so the OP is probably doubly out of luck.
$endgroup$
– Starfish Prime
8 hours ago
5
$begingroup$
@StarfishPrime yeah it would take an infinite amount of bonding energy to have infinite tensile strength. Energy=mass so the object would have infinite mass. So the universe would collapse in on it long before we are at infinite
$endgroup$
– Andrey
7 hours ago
$begingroup$
@Andrey ta, that's a nice, straightforward explanation. I'll remember that for future use!
$endgroup$
– Starfish Prime
7 hours ago
add a comment |
$begingroup$
I won't dare sticking my finger into the relativistic theory of rotating bodies, I will just go with the approximation of linear motion, which is valid for infinitesimal rotations.
We know that, by relativity, the mass of an object moving at velocity v is increased according to Lorentz factor $gamma=$$1 over sqrt1-v^2/c^2$.
Therefore, the more the tangential velocity of the disc increases, the more its mass increases, the more becomes difficult to increase its velocity. Moreover, being a rotating body, we also need to take into account the increase in centripetal force, which would sooner or later overcome the resistance of the material.
My guess is that the disc will break way before any relativistic effect can be sensed (ask any turbine manufacturer).
answered 8 hours ago
L.Dutch♦L.Dutch
97.9k31230473
$endgroup$
I won't dare sticking my finger into the relativistic theory of rotating bodies, I will just go with the approximation of linear motion, which is valid for infinitesimal rotations.
We know that, by relativity, the mass of an object moving at velocity v is increased according to Lorentz factor $gamma=$$1 over sqrt1-v^2/c^2$.
Therefore, the more the tangential velocity of the disc increases, the more its mass increases, the more becomes difficult to increase its velocity. Moreover, being a rotating body, we also need to take into account the increase in centripetal force, which would sooner or later overcome the resistance of the material.
My guess is that the disc will break way before any relativistic effect can be sensed (ask any turbine manufacturer).
answered 8 hours ago
L.Dutch♦L.Dutch
97.9k31230473
edited 7 hours ago
answered 8 hours ago
L.Dutch♦L.Dutch
97.9k31230473
answered 8 hours ago
L.Dutch♦L.Dutch
97.9k31230473
answered 8 hours ago
L.Dutch♦L.Dutch
97.9k31230473
97.9k31230473
4
$begingroup$
I've a sneaking suspicion that any material with infinite tensile strength is itself a violation of relativity (in the same way that a magical incompressible rod is). I'm not sure how the untearable disc causes physics to break... maybe you get Weirdness when you try to feed it into a black hole, so the OP is probably doubly out of luck.
$endgroup$
– Starfish Prime
8 hours ago
5
$begingroup$
@StarfishPrime yeah it would take an infinite amount of bonding energy to have infinite tensile strength. Energy=mass so the object would have infinite mass. So the universe would collapse in on it long before we are at infinite
$endgroup$
– Andrey
7 hours ago
$begingroup$
@Andrey ta, that's a nice, straightforward explanation. I'll remember that for future use!
$endgroup$
– Starfish Prime
7 hours ago
add a comment |
4
$begingroup$
I've a sneaking suspicion that any material with infinite tensile strength is itself a violation of relativity (in the same way that a magical incompressible rod is). I'm not sure how the untearable disc causes physics to break... maybe you get Weirdness when you try to feed it into a black hole, so the OP is probably doubly out of luck.
$endgroup$
– Starfish Prime
8 hours ago
5
$begingroup$
@StarfishPrime yeah it would take an infinite amount of bonding energy to have infinite tensile strength. Energy=mass so the object would have infinite mass. So the universe would collapse in on it long before we are at infinite
$endgroup$
– Andrey
7 hours ago
$begingroup$
@Andrey ta, that's a nice, straightforward explanation. I'll remember that for future use!
$endgroup$
– Starfish Prime
7 hours ago
4
4
$begingroup$
I've a sneaking suspicion that any material with infinite tensile strength is itself a violation of relativity (in the same way that a magical incompressible rod is). I'm not sure how the untearable disc causes physics to break... maybe you get Weirdness when you try to feed it into a black hole, so the OP is probably doubly out of luck.
$endgroup$
– Starfish Prime
8 hours ago
$begingroup$
I've a sneaking suspicion that any material with infinite tensile strength is itself a violation of relativity (in the same way that a magical incompressible rod is). I'm not sure how the untearable disc causes physics to break... maybe you get Weirdness when you try to feed it into a black hole, so the OP is probably doubly out of luck.
$endgroup$
– Starfish Prime
8 hours ago
5
5
$begingroup$
@StarfishPrime yeah it would take an infinite amount of bonding energy to have infinite tensile strength. Energy=mass so the object would have infinite mass. So the universe would collapse in on it long before we are at infinite
$endgroup$
– Andrey
7 hours ago
$begingroup$
@StarfishPrime yeah it would take an infinite amount of bonding energy to have infinite tensile strength. Energy=mass so the object would have infinite mass. So the universe would collapse in on it long before we are at infinite
$endgroup$
– Andrey
7 hours ago
$begingroup$
@Andrey ta, that's a nice, straightforward explanation. I'll remember that for future use!
$endgroup$
– Starfish Prime
7 hours ago
$begingroup$
@Andrey ta, that's a nice, straightforward explanation. I'll remember that for future use!
$endgroup$
– Starfish Prime
7 hours ago
add a comment |
$begingroup$
I was once where you are.
I wondered if it was possible to create a rotating mirrored propeller capable of spinning fast enough to separate particle pairs in the quantum foam in a manner reminiscent of a Quantum Vacuum plasma thruster.
The answer is no. The reason is material stress.
Basically the maximum stress on a rotating solid disc (or arm) scales as the square of both disc radius and orbital velocity. This means that long before the edge of your disc is moving anywhere near C the disc itself is being put under stresses usually reserved for... erm... supernovae? Possibly freshly expanding galaxies.
Either way: it was a while back when I ran the numbers, but suffice it to say that your disc will have broken apart looong before you get up to these kinds of speeds.
answered 7 hours ago
Joe BloggsJoe Bloggs
38k20106190
$endgroup$
add a comment |
$begingroup$
I was once where you are.
I wondered if it was possible to create a rotating mirrored propeller capable of spinning fast enough to separate particle pairs in the quantum foam in a manner reminiscent of a Quantum Vacuum plasma thruster.
The answer is no. The reason is material stress.
Basically the maximum stress on a rotating solid disc (or arm) scales as the square of both disc radius and orbital velocity. This means that long before the edge of your disc is moving anywhere near C the disc itself is being put under stresses usually reserved for... erm... supernovae? Possibly freshly expanding galaxies.
Either way: it was a while back when I ran the numbers, but suffice it to say that your disc will have broken apart looong before you get up to these kinds of speeds.
answered 7 hours ago
Joe BloggsJoe Bloggs
38k20106190
$endgroup$
add a comment |
$begingroup$
I was once where you are.
I wondered if it was possible to create a rotating mirrored propeller capable of spinning fast enough to separate particle pairs in the quantum foam in a manner reminiscent of a Quantum Vacuum plasma thruster.
The answer is no. The reason is material stress.
Basically the maximum stress on a rotating solid disc (or arm) scales as the square of both disc radius and orbital velocity. This means that long before the edge of your disc is moving anywhere near C the disc itself is being put under stresses usually reserved for... erm... supernovae? Possibly freshly expanding galaxies.
Either way: it was a while back when I ran the numbers, but suffice it to say that your disc will have broken apart looong before you get up to these kinds of speeds.
answered 7 hours ago
Joe BloggsJoe Bloggs
38k20106190
$endgroup$
I was once where you are.
I wondered if it was possible to create a rotating mirrored propeller capable of spinning fast enough to separate particle pairs in the quantum foam in a manner reminiscent of a Quantum Vacuum plasma thruster.
The answer is no. The reason is material stress.
Basically the maximum stress on a rotating solid disc (or arm) scales as the square of both disc radius and orbital velocity. This means that long before the edge of your disc is moving anywhere near C the disc itself is being put under stresses usually reserved for... erm... supernovae? Possibly freshly expanding galaxies.
Either way: it was a while back when I ran the numbers, but suffice it to say that your disc will have broken apart looong before you get up to these kinds of speeds.
answered 7 hours ago
Joe BloggsJoe Bloggs
38k20106190
answered 7 hours ago
Joe BloggsJoe Bloggs
38k20106190
answered 7 hours ago
Joe BloggsJoe Bloggs
38k20106190
answered 7 hours ago
Joe BloggsJoe Bloggs
38k20106190
38k20106190
add a comment |
add a comment |
$begingroup$
Millisecond pulsars! Gravity waves! Imperial to metric conversions!
60 mile diameter disc.
188 mile circumference.
1000 rotations per second = 188 * 1000 miles / second = 188,000 miles/second
Speed of light = 299 792 458 m / s = 186282 miles / second.
The edge would be going faster than the speed of light; not allowed.
Here is a fine and relevant answer lifted from the astronomy stack, which asks about neutron stars. The one is question rotates at 25% of the speed of light. Go visit and upvote!
https://astronomy.stackexchange.com/questions/1291/what-is-the-fastest-spinning-rotation-of-a-neutron-star
The answer cites this wikipedia article
https://en.wikipedia.org/wiki/Millisecond_pulsar
with this text
Current theories of neutron star structure and evolution predict that
pulsars would break apart if they spun at a rate of c. 1500 rotations
per second or more, and that at a rate of above about 1000
rotations per second they would lose energy by gravitational radiation
faster than the accretion process would speed them up.
The cool thing for me here "lose energy by gravitational radiation". Huh?? I knew about gravity waves but did not realize that the production of gravity waves would allow a thing to slough energy! https://en.wikipedia.org/wiki/Gravitational_wave
There is the solution for how dark matter sheds accumulated energy on descending into a gravity well - as gravity waves!
OK; the saw blade. It will need to go slower. But you can make it out of a handy millisecond pulsar and still have it go plenty fast.
answered 3 hours ago
WillkWillk
125k29232518
$endgroup$
add a comment |
$begingroup$
Millisecond pulsars! Gravity waves! Imperial to metric conversions!
60 mile diameter disc.
188 mile circumference.
1000 rotations per second = 188 * 1000 miles / second = 188,000 miles/second
Speed of light = 299 792 458 m / s = 186282 miles / second.
The edge would be going faster than the speed of light; not allowed.
Here is a fine and relevant answer lifted from the astronomy stack, which asks about neutron stars. The one is question rotates at 25% of the speed of light. Go visit and upvote!
https://astronomy.stackexchange.com/questions/1291/what-is-the-fastest-spinning-rotation-of-a-neutron-star
The answer cites this wikipedia article
https://en.wikipedia.org/wiki/Millisecond_pulsar
with this text
Current theories of neutron star structure and evolution predict that
pulsars would break apart if they spun at a rate of c. 1500 rotations
per second or more, and that at a rate of above about 1000
rotations per second they would lose energy by gravitational radiation
faster than the accretion process would speed them up.
The cool thing for me here "lose energy by gravitational radiation". Huh?? I knew about gravity waves but did not realize that the production of gravity waves would allow a thing to slough energy! https://en.wikipedia.org/wiki/Gravitational_wave
There is the solution for how dark matter sheds accumulated energy on descending into a gravity well - as gravity waves!
OK; the saw blade. It will need to go slower. But you can make it out of a handy millisecond pulsar and still have it go plenty fast.
answered 3 hours ago
WillkWillk
125k29232518
$endgroup$
add a comment |
$begingroup$
Millisecond pulsars! Gravity waves! Imperial to metric conversions!
60 mile diameter disc.
188 mile circumference.
1000 rotations per second = 188 * 1000 miles / second = 188,000 miles/second
Speed of light = 299 792 458 m / s = 186282 miles / second.
The edge would be going faster than the speed of light; not allowed.
Here is a fine and relevant answer lifted from the astronomy stack, which asks about neutron stars. The one is question rotates at 25% of the speed of light. Go visit and upvote!
https://astronomy.stackexchange.com/questions/1291/what-is-the-fastest-spinning-rotation-of-a-neutron-star
The answer cites this wikipedia article
https://en.wikipedia.org/wiki/Millisecond_pulsar
with this text
Current theories of neutron star structure and evolution predict that
pulsars would break apart if they spun at a rate of c. 1500 rotations
per second or more, and that at a rate of above about 1000
rotations per second they would lose energy by gravitational radiation
faster than the accretion process would speed them up.
The cool thing for me here "lose energy by gravitational radiation". Huh?? I knew about gravity waves but did not realize that the production of gravity waves would allow a thing to slough energy! https://en.wikipedia.org/wiki/Gravitational_wave
There is the solution for how dark matter sheds accumulated energy on descending into a gravity well - as gravity waves!
OK; the saw blade. It will need to go slower. But you can make it out of a handy millisecond pulsar and still have it go plenty fast.
answered 3 hours ago
WillkWillk
125k29232518
$endgroup$
Millisecond pulsars! Gravity waves! Imperial to metric conversions!
60 mile diameter disc.
188 mile circumference.
1000 rotations per second = 188 * 1000 miles / second = 188,000 miles/second
Speed of light = 299 792 458 m / s = 186282 miles / second.
The edge would be going faster than the speed of light; not allowed.
Here is a fine and relevant answer lifted from the astronomy stack, which asks about neutron stars. The one is question rotates at 25% of the speed of light. Go visit and upvote!
https://astronomy.stackexchange.com/questions/1291/what-is-the-fastest-spinning-rotation-of-a-neutron-star
The answer cites this wikipedia article
https://en.wikipedia.org/wiki/Millisecond_pulsar
with this text
Current theories of neutron star structure and evolution predict that
pulsars would break apart if they spun at a rate of c. 1500 rotations
per second or more, and that at a rate of above about 1000
rotations per second they would lose energy by gravitational radiation
faster than the accretion process would speed them up.
The cool thing for me here "lose energy by gravitational radiation". Huh?? I knew about gravity waves but did not realize that the production of gravity waves would allow a thing to slough energy! https://en.wikipedia.org/wiki/Gravitational_wave
There is the solution for how dark matter sheds accumulated energy on descending into a gravity well - as gravity waves!
OK; the saw blade. It will need to go slower. But you can make it out of a handy millisecond pulsar and still have it go plenty fast.
answered 3 hours ago
WillkWillk
125k29232518
answered 3 hours ago
WillkWillk
125k29232518
answered 3 hours ago
WillkWillk
125k29232518
answered 3 hours ago
WillkWillk
125k29232518
125k29232518
add a comment |
add a comment |
Philip Thomas is a new contributor. Be nice, and check out our Code of Conduct.
Philip Thomas is a new contributor. Be nice, and check out our Code of Conduct.
Philip Thomas is a new contributor. Be nice, and check out our Code of Conduct.
Philip Thomas is a new contributor. Be nice, and check out our Code of Conduct.
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Downvotes without comment are unhelpful and unproductive.
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– Starfish Prime
9 hours ago
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This seems like a question better suited for another site, but suffice to say: relativity will probably give you all the answers you need. Lack of torque isn't precisely the problem you face, but relativistic mass gain certainly won't help.
$endgroup$
– Starfish Prime
9 hours ago
4
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On physics.stackexchange: Rotate a long bar in space and get close to (or even beyond) the speed of light 𝑐
$endgroup$
– Alexander
8 hours ago
$begingroup$
@StarfishPrime Yes. I'm beginning to see that the physics for mass gain is the same whether for rotation or linear. It wasn't obvious to me at first.
$endgroup$
– Philip Thomas
8 hours ago