Warping Space, Time, and Distance

We agree that the International Space Station is in orbit around the Earth, right? If we were to move the ISS half-way between the Earth and Moon, if its velocity / speed remained the same as it is now, it would quickly leave orbit: it must slow down in order to maintain a relatively stable orbit. If the Moon were closer to the Earth, it would have to speed up to remain in orbit.

The gravitaional effect the Sun has on any planet, or any other thing in the solar system for that matter, is going to depend upon the mass of the Sun, the mass of the object and the object's vector of motion: how fast and what direction the object is moving.

Jupiter has a mass roughly 318 times that of the Earth and an orbital period of roughly 11.9 "Earth years".
Saturn has a mass roughly 95.1 times that of the Earth and an orbital period of roughly 29.5 "Earth years".
Saturn's lower mass (compared to Jupiter) bombined with its greater distance from the Sun means it must travel more slowly than Jupiter to maintain a stable orbit.

Similar applies to Neptune and every other body in the solar system.

reply to post by jiggerj


is this the image you were looking for?


nasaimages.org...

Taken from 3.7 billion miles away

Also shows Venus and Earth as too little specks, you gotta zoom in to see it

reply to post by jiggerj


The gravitational pull of the planets is very small compared to the Sun. They do have an effect (it's one of the reasons orbits aren't perfectly circular), but it's nothing spectacular since the planets are far enough apart.

Originally posted by Kr0nZ
reply to post by jiggerj

 

is this the image you were looking for?


nasaimages.org...

Taken from 3.7 billion miles away

Also shows Venus and Earth as too little specks, you gotta zoom in to see it

That's it! Thanks, but of course, now I don't need it.

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Just to interject this...I recall some NASA report of time dilation's measured at the poles using precision time pieces and a balloon .. ?

So the event horizon of our planet displays time dilation's like a mini black hole ...


found it ..

www.youtube.com...

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reply to post by R0CR13


That was an experiment demonstrating frame dragging (not time dilation) at the poles caused by the Earth's rotation. The Earth has no event horizon...frame dragging is caused by any rotating (or otherwise moving) mass.

Originally posted by CLPrime
reply to post by jiggerj

 

The gravitational pull of the planets is very small compared to the Sun. They do have an effect (it's one of the reasons orbits aren't perfectly circular), but it's nothing spectacular since the planets are far enough apart.

I wasn't thinking so much as each planet's gravitational pull but as each planet blocking the sun's hold on Neptune. Seems with a mass as great as a planet it shouldn't take much to knock it out of its orbit. If it's velocity remains constant, with the sun's pull even slightly diminished it should be So Long Neptune! Send us a postcard!

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reply to post by CLPrime



Did you watch the video it explains it better than I .

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reply to post by jiggerj


Gravity is the warping of spacetime. There's nothing to block.
If you put a bowling ball in the middle of a mattress, will putting a second bowling ball next to it block the depression of the mattress caused by the first bowling bal?

reply to post by R0CR13


I don't have to watch the video, I know what it's talking about. And it does explain it better than you, but not everyone will watch the video...so I explained it better than you too. Most importantly, there is no event horizon around the Earth.

Originally posted by R0CR13
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Just to interject this...I recall some NASA report of time dilation's measured at the poles using precision time pieces and a balloon .. ?

So the event horizon of our planet displays time dilation's like a mini black hole ...


found it ..

www.youtube.com...

Thanks for the clip. In the first minute I think it was saying that planets don't roll around on the curvature of space-time, but that the curvature moves, taking the planet along for the ride. Is this right?

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Originally posted by CLPrime
reply to post by jiggerj

 

Gravity is the warping of spacetime. There's nothing to block.
If you put a bowling ball in the middle of a mattress, will putting a second bowling ball next to it block the depression of the mattress caused by the first bowling bal?

No, it would widen the depression, causing a THIRD ball placed further away to roll into the center, when it wouldn't have with just the one ball in the middle of the mattress.

Originally posted by CLPrime
reply to post by jiggerj

 

Gravity is the warping of spacetime.

Please explain how the warping of space-time works on keeping everything down on this planet? Or, are there two different types of gravity?

reply to post by jiggerj


That's right.
In the case of the Sun and planets, the Sun is a bowling ball in the middle and the planets are marbles. Compared to the warping caused by the Sun, the warping caused by the planets amount to very little. As I said before, the only thing they do, really, is cause the orbits of the planets to not be perfectly circular.

reply to post by jiggerj


You got to remeber that 3 billion miles only seems far to are human perspectives, but really 3 billion miles is very small on the cosmic scale of things.

reply to post by jiggerj


Nope, there's one kind of gravity. This is where the standard image of gravity (a ball causing a well in some material) doesn't work, because it's a 2-dimensional visualization when gravity acts in all 4 dimensions. Things don't "roll" around in depressions. If you think about it for a moment, you should realize why. In the 'bowling ball-matress' example, what's causing the marble to roll down the depression caused by the bowling ball? Gravity, of course. But there is no external force of gravity causing planets to roll down into the gravity wells formed by stars. That's why the 2-dimensional picture tends to eventually fail.

Correctly modelling the gravity well requires Calculus and and an understanding of the curvature of tensor fields, not to mention an understanding Einstein's field equations. These are hard, if not impossible, to visualize, which is why we usually stick with the 'bowling ball on a mattress' scenario.

Essentially: objects stay on the surface of the Earth because the 4-dimensional curvature of the spacetime surrounding the Earth is a tensor field that translates to an acceleration sufficient to literally force objects into the surface of the Earth. We are constantly being accelerated into the ground by this curvature, it just happens that the ground is strong enough to restrain that constant acceleration. This restraining force is called the Normal force, and it's mostly found in high school physics.

reply to post by CLPrime


about your last post.... is this an accurate description of earths gravity; do you know the carnival ride "the gravitron? if the gravitron was rotating as it does, and moving it self at a decent speed,

Einsteins theory of relativity involved that very premise of gravity bending light. A huge effort was undertaken to capture that effect during succeeding eclipses. They were ultimately successful and the proof was determined with just the distance from the earth to the sun. About 92 million miles. I don't have a link for all that just now... if someone already mentioned it please forgive me. The light traveling throughout the Universe has been bent around so many times I wonder if the actual size of it is much smaller. We just think that is a different part of space but really we are just seeing ourselves from a different angle? Dunno...

Einstein Ring

So many answers relating to Gravity seem to expect the reader to understand Gravity, when it seems science itself doesnt understand gravity.

Why is gravity so week, why does gravity only pull ( it doesnt seem to have an anti mechanism), What is the instantaneous action at distance, what mediates gravity- is there a Graviton??? etc etc

Look up Quantum Space Time for a neat explanation of how Quantised Space explains the TS question without haviing to invent magic particles or expect you to believe that objects "roll" around space....as if space is a 2d surface....

BTW I;d be interested to hear from the resident Gravity experts on exactly which dimension the (Already 3 Dimenisonal) Planet seems to sag in to create the "gravity well " in the Euclidian geometery expalantion as shown in jiggerj's pic...we seem to have a 3d object with its own x,y,z coordinates moving through another dimension whilst alos affecting another 3d object ??

Originally posted by intrptr
Einsteins theory of relativity involved that very premise of gravity bending light. A huge effort was undertaken to capture that effect during succeeding eclipses. They were ultimately successful and the proof was determined with just the distance from the earth to the sun. About 92 million miles. I don't have a link for all that just now... if someone already mentioned it please forgive me. The light traveling throughout the Universe has been bent around so many times I wonder if the actual size of it is much smaller. We just think that is a different part of space but really we are just seeing ourselves from a different angle? Dunno...

Einstein Ring

Thanks for link - Also there is the Einstein Cross
This is created when one distant galaxy or quasar aligns behind another causing 5 light sources to appear - One central light and 4 on quadrants

en.wikipedia.org...