Gravitational time dilation compensated by acceleration
$begingroup$
I would like to compare the time indicated by two clocks: clock A is located at the top of a mountain, the clock B is in an helicopter flying stationnary at the same altitude than the clock A.
Clock A and B are at rest with each other and located at the same altitude. Clock A has a 0 proper acceleration, and clock B has a non zero proper acceleration (is it correct ?).
If we neglect the Earth rotation/tidal effects, does the general relativity predicts that both clocks will be equivalent thanks to the clock hypothesis ?
Why this simple experiment has never been done, instead of sending 2 planes in opposite directions with complex trajectories ?
Thank you!
general-relativity time-dilation
asked 11 hours ago
François RitterFrançois Ritter
606
$endgroup$
add a comment |
$begingroup$
I would like to compare the time indicated by two clocks: clock A is located at the top of a mountain, the clock B is in an helicopter flying stationnary at the same altitude than the clock A.
Clock A and B are at rest with each other and located at the same altitude. Clock A has a 0 proper acceleration, and clock B has a non zero proper acceleration (is it correct ?).
If we neglect the Earth rotation/tidal effects, does the general relativity predicts that both clocks will be equivalent thanks to the clock hypothesis ?
Why this simple experiment has never been done, instead of sending 2 planes in opposite directions with complex trajectories ?
Thank you!
general-relativity time-dilation
asked 11 hours ago
François RitterFrançois Ritter
606
$endgroup$
$begingroup$
I am curious why you come to your original assumption: There are two close-by objects which are not moving relative to each other. How could one be accelerated while the the other one is not? Is it that the one on the mountain is suspended by solid matter while the one in the helicopter is (at least indirectly) suspended by gaseous matter? That should not, well, matter. Is it that the helicopter must burn fuel in order to stay aloft? It is a bit unintuitive, but there is no energy transferred to or from the object; it is all wasted by heating the air.
$endgroup$
– Peter A. Schneider
41 mins ago
add a comment |
$begingroup$
I would like to compare the time indicated by two clocks: clock A is located at the top of a mountain, the clock B is in an helicopter flying stationnary at the same altitude than the clock A.
Clock A and B are at rest with each other and located at the same altitude. Clock A has a 0 proper acceleration, and clock B has a non zero proper acceleration (is it correct ?).
If we neglect the Earth rotation/tidal effects, does the general relativity predicts that both clocks will be equivalent thanks to the clock hypothesis ?
Why this simple experiment has never been done, instead of sending 2 planes in opposite directions with complex trajectories ?
Thank you!
general-relativity time-dilation
asked 11 hours ago
François RitterFrançois Ritter
606
$endgroup$
I would like to compare the time indicated by two clocks: clock A is located at the top of a mountain, the clock B is in an helicopter flying stationnary at the same altitude than the clock A.
Clock A and B are at rest with each other and located at the same altitude. Clock A has a 0 proper acceleration, and clock B has a non zero proper acceleration (is it correct ?).
If we neglect the Earth rotation/tidal effects, does the general relativity predicts that both clocks will be equivalent thanks to the clock hypothesis ?
Why this simple experiment has never been done, instead of sending 2 planes in opposite directions with complex trajectories ?
Thank you!
general-relativity time-dilation
general-relativity time-dilation
asked 11 hours ago
François RitterFrançois Ritter
606
asked 11 hours ago
François RitterFrançois Ritter
606
asked 11 hours ago
François RitterFrançois Ritter
606
asked 11 hours ago
François RitterFrançois Ritter
606
asked 11 hours ago
François RitterFrançois Ritter
606
606
$begingroup$
I am curious why you come to your original assumption: There are two close-by objects which are not moving relative to each other. How could one be accelerated while the the other one is not? Is it that the one on the mountain is suspended by solid matter while the one in the helicopter is (at least indirectly) suspended by gaseous matter? That should not, well, matter. Is it that the helicopter must burn fuel in order to stay aloft? It is a bit unintuitive, but there is no energy transferred to or from the object; it is all wasted by heating the air.
$endgroup$
– Peter A. Schneider
41 mins ago
add a comment |
$begingroup$
I am curious why you come to your original assumption: There are two close-by objects which are not moving relative to each other. How could one be accelerated while the the other one is not? Is it that the one on the mountain is suspended by solid matter while the one in the helicopter is (at least indirectly) suspended by gaseous matter? That should not, well, matter. Is it that the helicopter must burn fuel in order to stay aloft? It is a bit unintuitive, but there is no energy transferred to or from the object; it is all wasted by heating the air.
$endgroup$
– Peter A. Schneider
41 mins ago
$begingroup$
I am curious why you come to your original assumption: There are two close-by objects which are not moving relative to each other. How could one be accelerated while the the other one is not? Is it that the one on the mountain is suspended by solid matter while the one in the helicopter is (at least indirectly) suspended by gaseous matter? That should not, well, matter. Is it that the helicopter must burn fuel in order to stay aloft? It is a bit unintuitive, but there is no energy transferred to or from the object; it is all wasted by heating the air.
$endgroup$
– Peter A. Schneider
41 mins ago
$begingroup$
I am curious why you come to your original assumption: There are two close-by objects which are not moving relative to each other. How could one be accelerated while the the other one is not? Is it that the one on the mountain is suspended by solid matter while the one in the helicopter is (at least indirectly) suspended by gaseous matter? That should not, well, matter. Is it that the helicopter must burn fuel in order to stay aloft? It is a bit unintuitive, but there is no energy transferred to or from the object; it is all wasted by heating the air.
$endgroup$
– Peter A. Schneider
41 mins ago
add a comment |
2 Answers
2
active
oldest
votes
$begingroup$
Both clocks have the same proper acceleration. The calculation of the proper acceleration is described in What is the weight equation through general relativity? The proper acceleration for an object stationary at a distance $r$ from the centre of the Earth turns out to be:
$$ A = frac{GM}{r^2}frac{1}{sqrt{1-frac{2GM}{c^2r}}} $$
It makes no difference that one clock is stationary on a mountain at the distance $r$ from the centre of the Earth while the other is stationary in a helicopter at the distance $r$ from the centre of the Earth.
answered 10 hours ago
John RennieJohn Rennie
275k43546791
$endgroup$
$begingroup$
Wikipedia " Gravitation therefore does not cause proper acceleration, since gravity acts upon the inertial observer that any proper acceleration must depart from. A corollary is that all inertial observers always have a proper acceleration of zero."... so gravitation causes a proper acceleration and this wikipedia page is wrong ?
$endgroup$
– François Ritter
10 hours ago
2
$begingroup$
@FrançoisRitter that means an object falling freely under gravity has a zero proper acceleration. The objects in your question are being held stationary not falling freely.
$endgroup$
– John Rennie
10 hours ago
$begingroup$
Thank you so much !
$endgroup$
– François Ritter
10 hours ago
add a comment |
$begingroup$
The reference frames of clock $A$ and clock $B$ are equivalent. They are stationary with respect to the spacetime given by the earth mass/energy at the same radial coordinate. They measure a proper acceleration as the frames are not along a geodesic.
The time of clock $A$ and clock $B$ runs with the same rate.
answered 10 hours ago
Michele GrossoMichele Grosso
1,830212
$endgroup$
add a comment |
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2 Answers
2
active
oldest
votes
2 Answers
2
active
oldest
votes
active
oldest
votes
active
oldest
votes
$begingroup$
Both clocks have the same proper acceleration. The calculation of the proper acceleration is described in What is the weight equation through general relativity? The proper acceleration for an object stationary at a distance $r$ from the centre of the Earth turns out to be:
$$ A = frac{GM}{r^2}frac{1}{sqrt{1-frac{2GM}{c^2r}}} $$
It makes no difference that one clock is stationary on a mountain at the distance $r$ from the centre of the Earth while the other is stationary in a helicopter at the distance $r$ from the centre of the Earth.
answered 10 hours ago
John RennieJohn Rennie
275k43546791
$endgroup$
$begingroup$
Wikipedia " Gravitation therefore does not cause proper acceleration, since gravity acts upon the inertial observer that any proper acceleration must depart from. A corollary is that all inertial observers always have a proper acceleration of zero."... so gravitation causes a proper acceleration and this wikipedia page is wrong ?
$endgroup$
– François Ritter
10 hours ago
2
$begingroup$
@FrançoisRitter that means an object falling freely under gravity has a zero proper acceleration. The objects in your question are being held stationary not falling freely.
$endgroup$
– John Rennie
10 hours ago
$begingroup$
Thank you so much !
$endgroup$
– François Ritter
10 hours ago
add a comment |
$begingroup$
Both clocks have the same proper acceleration. The calculation of the proper acceleration is described in What is the weight equation through general relativity? The proper acceleration for an object stationary at a distance $r$ from the centre of the Earth turns out to be:
$$ A = frac{GM}{r^2}frac{1}{sqrt{1-frac{2GM}{c^2r}}} $$
It makes no difference that one clock is stationary on a mountain at the distance $r$ from the centre of the Earth while the other is stationary in a helicopter at the distance $r$ from the centre of the Earth.
answered 10 hours ago
John RennieJohn Rennie
275k43546791
$endgroup$
$begingroup$
Wikipedia " Gravitation therefore does not cause proper acceleration, since gravity acts upon the inertial observer that any proper acceleration must depart from. A corollary is that all inertial observers always have a proper acceleration of zero."... so gravitation causes a proper acceleration and this wikipedia page is wrong ?
$endgroup$
– François Ritter
10 hours ago
2
$begingroup$
@FrançoisRitter that means an object falling freely under gravity has a zero proper acceleration. The objects in your question are being held stationary not falling freely.
$endgroup$
– John Rennie
10 hours ago
$begingroup$
Thank you so much !
$endgroup$
– François Ritter
10 hours ago
add a comment |
$begingroup$
Both clocks have the same proper acceleration. The calculation of the proper acceleration is described in What is the weight equation through general relativity? The proper acceleration for an object stationary at a distance $r$ from the centre of the Earth turns out to be:
$$ A = frac{GM}{r^2}frac{1}{sqrt{1-frac{2GM}{c^2r}}} $$
It makes no difference that one clock is stationary on a mountain at the distance $r$ from the centre of the Earth while the other is stationary in a helicopter at the distance $r$ from the centre of the Earth.
answered 10 hours ago
John RennieJohn Rennie
275k43546791
$endgroup$
Both clocks have the same proper acceleration. The calculation of the proper acceleration is described in What is the weight equation through general relativity? The proper acceleration for an object stationary at a distance $r$ from the centre of the Earth turns out to be:
$$ A = frac{GM}{r^2}frac{1}{sqrt{1-frac{2GM}{c^2r}}} $$
It makes no difference that one clock is stationary on a mountain at the distance $r$ from the centre of the Earth while the other is stationary in a helicopter at the distance $r$ from the centre of the Earth.
answered 10 hours ago
John RennieJohn Rennie
275k43546791
answered 10 hours ago
John RennieJohn Rennie
275k43546791
answered 10 hours ago
John RennieJohn Rennie
275k43546791
answered 10 hours ago
John RennieJohn Rennie
275k43546791
275k43546791
$begingroup$
Wikipedia " Gravitation therefore does not cause proper acceleration, since gravity acts upon the inertial observer that any proper acceleration must depart from. A corollary is that all inertial observers always have a proper acceleration of zero."... so gravitation causes a proper acceleration and this wikipedia page is wrong ?
$endgroup$
– François Ritter
10 hours ago
2
$begingroup$
@FrançoisRitter that means an object falling freely under gravity has a zero proper acceleration. The objects in your question are being held stationary not falling freely.
$endgroup$
– John Rennie
10 hours ago
$begingroup$
Thank you so much !
$endgroup$
– François Ritter
10 hours ago
add a comment |
$begingroup$
Wikipedia " Gravitation therefore does not cause proper acceleration, since gravity acts upon the inertial observer that any proper acceleration must depart from. A corollary is that all inertial observers always have a proper acceleration of zero."... so gravitation causes a proper acceleration and this wikipedia page is wrong ?
$endgroup$
– François Ritter
10 hours ago
2
$begingroup$
@FrançoisRitter that means an object falling freely under gravity has a zero proper acceleration. The objects in your question are being held stationary not falling freely.
$endgroup$
– John Rennie
10 hours ago
$begingroup$
Thank you so much !
$endgroup$
– François Ritter
10 hours ago
$begingroup$
Wikipedia " Gravitation therefore does not cause proper acceleration, since gravity acts upon the inertial observer that any proper acceleration must depart from. A corollary is that all inertial observers always have a proper acceleration of zero."... so gravitation causes a proper acceleration and this wikipedia page is wrong ?
$endgroup$
– François Ritter
10 hours ago
$begingroup$
Wikipedia " Gravitation therefore does not cause proper acceleration, since gravity acts upon the inertial observer that any proper acceleration must depart from. A corollary is that all inertial observers always have a proper acceleration of zero."... so gravitation causes a proper acceleration and this wikipedia page is wrong ?
$endgroup$
– François Ritter
10 hours ago
2
2
$begingroup$
@FrançoisRitter that means an object falling freely under gravity has a zero proper acceleration. The objects in your question are being held stationary not falling freely.
$endgroup$
– John Rennie
10 hours ago
$begingroup$
@FrançoisRitter that means an object falling freely under gravity has a zero proper acceleration. The objects in your question are being held stationary not falling freely.
$endgroup$
– John Rennie
10 hours ago
$begingroup$
Thank you so much !
$endgroup$
– François Ritter
10 hours ago
$begingroup$
Thank you so much !
$endgroup$
– François Ritter
10 hours ago
add a comment |
$begingroup$
The reference frames of clock $A$ and clock $B$ are equivalent. They are stationary with respect to the spacetime given by the earth mass/energy at the same radial coordinate. They measure a proper acceleration as the frames are not along a geodesic.
The time of clock $A$ and clock $B$ runs with the same rate.
answered 10 hours ago
Michele GrossoMichele Grosso
1,830212
$endgroup$
add a comment |
$begingroup$
The reference frames of clock $A$ and clock $B$ are equivalent. They are stationary with respect to the spacetime given by the earth mass/energy at the same radial coordinate. They measure a proper acceleration as the frames are not along a geodesic.
The time of clock $A$ and clock $B$ runs with the same rate.
answered 10 hours ago
Michele GrossoMichele Grosso
1,830212
$endgroup$
add a comment |
$begingroup$
The reference frames of clock $A$ and clock $B$ are equivalent. They are stationary with respect to the spacetime given by the earth mass/energy at the same radial coordinate. They measure a proper acceleration as the frames are not along a geodesic.
The time of clock $A$ and clock $B$ runs with the same rate.
answered 10 hours ago
Michele GrossoMichele Grosso
1,830212
$endgroup$
The reference frames of clock $A$ and clock $B$ are equivalent. They are stationary with respect to the spacetime given by the earth mass/energy at the same radial coordinate. They measure a proper acceleration as the frames are not along a geodesic.
The time of clock $A$ and clock $B$ runs with the same rate.
answered 10 hours ago
Michele GrossoMichele Grosso
1,830212
answered 10 hours ago
Michele GrossoMichele Grosso
1,830212
answered 10 hours ago
Michele GrossoMichele Grosso
1,830212
answered 10 hours ago
Michele GrossoMichele Grosso
1,830212
1,830212
add a comment |
add a comment |
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$begingroup$
I am curious why you come to your original assumption: There are two close-by objects which are not moving relative to each other. How could one be accelerated while the the other one is not? Is it that the one on the mountain is suspended by solid matter while the one in the helicopter is (at least indirectly) suspended by gaseous matter? That should not, well, matter. Is it that the helicopter must burn fuel in order to stay aloft? It is a bit unintuitive, but there is no energy transferred to or from the object; it is all wasted by heating the air.
$endgroup$
– Peter A. Schneider
41 mins ago