Guido
A mass moving at a constant velocity does not emit gravity waves. Only when the velocity changes are gravity waves emitted.
Gotcha! In this case doesn't an abject in a non-circular orbit travel at a non-constant speed - such as a planet with an elliptical orbit? Shouldn't this planet emit gravity waves? And if these waves are measurable on the surface of said planet then wouldn't the weight of an object on the planet change depending on where in the orbit it is?
Guido
A mass moving at a constant velocity does not emit gravity waves. Only when the velocity changes are gravity waves emitted.
Gotcha! In this case doesn't an abject in a non-circular orbit travel at a non-constant speed - such as a planet with an elliptical orbit? Shouldn't this planet emit gravity waves? And if these waves are measurable on the surface of said planet then wouldn't the weight of an object on the planet change depending on where in the orbit it is?
Maybe EatH should be EonPluto haha
Guido,
Any object traveling at anything other than a linear path (vector) at a linear rate of motion is accelerating, therefore any orbit involves acceleration, because it's vector is continually changing.
microcraft
"The arc of history is long, but it bends toward justice" - MLK
Gotcha! In this case doesn't an abject in a non-circular orbit travel at a non-constant speed - such as a planet with an elliptical orbit? Shouldn't this planet emit gravity waves? And if these waves are measurable on the surface of said planet then wouldn't the weight of an object on the planet change depending on where in the orbit it is?
You are correct about objects emitted gravity waves at different rates if the orbits are elliptical and you are further correct that a third mass passing near the original pair of masses would be less strongly attracted. This is in part what Bruce Allen was talking about in his post.
But this trend would be consistently toward weaker attraction not weaker at some points and stronger at others.
Any object traveling at anything other than a linear path (vector) at a linear rate of motion is accelerating, therefore any orbit involves acceleration, because it's vector is continually changing.
Oh, I didn't know that. But it makes sense because the X and Y vectors are constantly changing (accelerating, both positive and negative).
But I assume the gravity waves emited from a perfect circular orbit would be constant (and difficult to measure because there is no change).
Would my "gravity meter" on Pluto experiment work? I think it would, only if you can measure gravity waves from the surface of a planet.
Any object traveling at anything other than a linear path (vector) at a linear rate of motion is accelerating, therefore any orbit involves acceleration, because it's vector is continually changing.
Oh, I didn't know that. But it makes sense because the X and Y vectors are constantly changing (accelerating, both positive and negative).
But I assume the gravity waves emited from a perfect circular orbit would be constant (and difficult to measure because there is no change).
Would my "gravity meter" on Pluto experiment work? I think it would, only if you can measure gravity waves from the surface of a planet.
Guido,
Here and now is the time and place for me to admit to my extreme ignorance regarding gravity waves and their propagation/detection. Physics was only my third subject path in college, behind Math and Chemistry, and all that happened in the early 1970s, so it's pretty much atrophied over the years, due to not being used on any regular basis.
microcraft
"The arc of history is long, but it bends toward justice" - MLK
But I assume the gravity waves emited from a perfect circular orbit would be constant
Right again at least initially. But then the masses would begin to spiral in toward each other. The GW emissions would get stronger as the inspiral continued.
Another point is that the GW's field not emitted equally in all directions. Rather they would be strongest along the line connecting the two masses.
Quote:
Would my "gravity meter" on Pluto experiment work? I think it would, only if you can measure gravity waves from the surface of a planet.
Yes, probably better than it would on earth. At least as long as you are looking for the same signal LIGO, GEO etc are. Signals from the earth/moon or earth/sun would be to weak.
The best non technical book on GR I"ve come across is "The riddle of gravitation" by Peter G.Bergmann, a coworker of Einstein, 1968, but I don't know if is still available and not out of print.I edited its Italian edition in 1969 for Edizioni Scientifiche Mondadori.
Tullio
I can look for this book, but even if I find it could it be out of date? Maybe our understanding has changed somewhat since 1968?
Anyway, it looks like there's more reading I need to do. (The hard part is remembering everything I read!)
Basic laws of nature do not change. I have been following GR and GW research since the Sixties and they are always based on Einstein's thinking.Gravity is still a riddle because it cannot be quantized, as opposed to the other three fundamental interactions.Why?
Tullio
Right again at least initially. But then the masses would begin to spiral in toward each other. The GW emissions would get stronger as the inspiral continued.
Another point is that the GW's field not emitted equally in all directions. Rather they would be strongest along the line connecting the two masses.
Let's see if I got this straight:
To objects are orbiting each other.
The constant acceleration (because it's not a straight-line, constant speed motion) creates gravity waves.
These waves are energy converted from mass.
As mass diminishes, the objects orbit closer together (and I think they accelerate too).
The cycle continues until they merge.
Do we know of any objects that we believe have merged from two orbiting objects? I imagine it would be spinning very fast and possibly very bright if it were two stars.
Anyone know where I can find Newton's fomula where I can input mass and distance of an orbiting object and it tells me velocity?
Quote:
Yes, probably better than it would on earth. At least as long as you are looking for the same signal LIGO, GEO etc are. Signals from the earth/moon or earth/sun would be to weak.
I'm right again... but by mistake. I picked pluto (instead of earth) because I thought the higher eccentricity would make it easier to detect the change in gravity wave strangth as the planet speeds up and slows down at the end of its major axis.
But since you mentioned the waves would be strongest along the sun to pluto line, then from our vantage point we should see a change in strength regardless if the orbit is circular or not .
Basic laws of nature do not change. I have been following GR and GW research since the Sixties and they are always based on Einstein's thinking.Gravity is still a riddle because it cannot be quantized, as opposed to the other three fundamental interactions.Why?
Tullio
Thanks, I'm going to the library tonight to look for it.
I'm right again... but by mistake. I picked pluto (instead of earth) because I thought the higher eccentricity would make it easier to detect the change in gravity wave strangth as the planet speeds up and slows down at the end of its major axis.
Guido, while you're at the library, you might be interested also in learning about LISA
RE: Guido A mass moving at
)
Gotcha! In this case doesn't an abject in a non-circular orbit travel at a non-constant speed - such as a planet with an elliptical orbit? Shouldn't this planet emit gravity waves? And if these waves are measurable on the surface of said planet then wouldn't the weight of an object on the planet change depending on where in the orbit it is?
Maybe EatH should be EonPluto haha
RE: RE: Guido A mass
)
Guido,
Any object traveling at anything other than a linear path (vector) at a linear rate of motion is accelerating, therefore any orbit involves acceleration, because it's vector is continually changing.
microcraft
"The arc of history is long, but it bends toward justice" - MLK
RE: Gotcha! In this case
)
You are correct about objects emitted gravity waves at different rates if the orbits are elliptical and you are further correct that a third mass passing near the original pair of masses would be less strongly attracted. This is in part what Bruce Allen was talking about in his post.
But this trend would be consistently toward weaker attraction not weaker at some points and stronger at others.
RE: Guido, Any object
)
Oh, I didn't know that. But it makes sense because the X and Y vectors are constantly changing (accelerating, both positive and negative).
But I assume the gravity waves emited from a perfect circular orbit would be constant (and difficult to measure because there is no change).
Would my "gravity meter" on Pluto experiment work? I think it would, only if you can measure gravity waves from the surface of a planet.
RE: RE: Guido, Any
)
Guido,
Here and now is the time and place for me to admit to my extreme ignorance regarding gravity waves and their propagation/detection. Physics was only my third subject path in college, behind Math and Chemistry, and all that happened in the early 1970s, so it's pretty much atrophied over the years, due to not being used on any regular basis.
microcraft
"The arc of history is long, but it bends toward justice" - MLK
RE: But I assume the
)
Right again at least initially. But then the masses would begin to spiral in toward each other. The GW emissions would get stronger as the inspiral continued.
Another point is that the GW's field not emitted equally in all directions. Rather they would be strongest along the line connecting the two masses.
Yes, probably better than it would on earth. At least as long as you are looking for the same signal LIGO, GEO etc are. Signals from the earth/moon or earth/sun would be to weak.
RE: RE: The best non
)
Basic laws of nature do not change. I have been following GR and GW research since the Sixties and they are always based on Einstein's thinking.Gravity is still a riddle because it cannot be quantized, as opposed to the other three fundamental interactions.Why?
Tullio
RE: Right again at least
)
Let's see if I got this straight:
To objects are orbiting each other.
The constant acceleration (because it's not a straight-line, constant speed motion) creates gravity waves.
These waves are energy converted from mass.
As mass diminishes, the objects orbit closer together (and I think they accelerate too).
The cycle continues until they merge.
Do we know of any objects that we believe have merged from two orbiting objects? I imagine it would be spinning very fast and possibly very bright if it were two stars.
Anyone know where I can find Newton's fomula where I can input mass and distance of an orbiting object and it tells me velocity?
I'm right again... but by mistake. I picked pluto (instead of earth) because I thought the higher eccentricity would make it easier to detect the change in gravity wave strangth as the planet speeds up and slows down at the end of its major axis.
But since you mentioned the waves would be strongest along the sun to pluto line, then from our vantage point we should see a change in strength regardless if the orbit is circular or not .
RE: Basic laws of nature
)
Thanks, I'm going to the library tonight to look for it.
RE: I'm right again... but
)
Guido, while you're at the library, you might be interested also in learning about LISA