Gravity speed experiment

chat · 2005-11-30 04:08:11

I was up late last night looking at Jupiter in the night sky when an interesting experiment to measure the speed of gravity came to mind.
Jupiter causing tides on earth should tell us where the tide bulge points to in relation to Jupiter, an exact measure of the speed of gravity.
If the Jupiter tide points to where Jupiter was 90ish minutes ago then the speed of gravity is light speed, if it points anywhere else then the speed is slower or faster than light speed.

With a few simple calculations we should be able to accurately measure the speed of gravity.
Anyone have Jupiter tide and actual Jupiter position data for the calculations, and a good calculator?

The same experiment could be done with the Moon, Mars or Venus and the same corresponding position data .

Rxke · 2005-11-30 04:36:00

Jupiter causing tides on earth

How would you measure that? Given the distance, the tidal effects would be pretty small, and probably be lost in the tidal forces exerted by Luna?

SpaceNut · 2005-11-30 06:34:50

In addition you would also need a time when Jupiter did not exert any tidal forces as well as for the moon or mars to prove out the speed or force amounts.

Rxke · 2005-11-30 06:38:47

In addition you would also need a time when Jupiter did not exert any tidal forces...

I don't understand, Jupiter is there, so it will *always* exert some force, what do you mean?

chat · 2005-11-30 07:30:51

SpaceNut,

We should be able to cancel out all other effects from all other gravitational influences and get a result one day to another.
Then simply look at where the bulge was pointing and true positions vs light positions.

Might make for an interesting result.

Still requires lots of data and a good calculator, more math than i would be involved in

Rxke,

The moon is always there, but where does the gravitational influence come from?
The current position of the moon, or where it was 8/10th of a second ago or some other time point?

With Jupiter we get a 90 minute delay on this gravitational influence, so an easy way to see if gravity tide bulge is influenced by the real position of Jupiter or where it was 90ish minutes ago. (light speed)

If the bulge is pointing to where we see Jupiter then gravity is light speed.
If it points to the real position of Jupiter, then gravity speed is instantaneous.
Or some other result might happen.

SpaceNut · 2005-11-30 09:14:20

My thought was to take the jupiter measurement when the earth is oposite of the sun of jupiter rather than on the same side for the initial low value of influence and then to take the same measurement once we are inline on the same side again.
Yes chat cancellation by lots of measurements at given conditions.

chat · 2005-11-30 15:14:52

SpaceNut,

Good idea for the minimum maximum influences, that would certainly allow for very precise measurements.

Probably stuck with the same sort of cancelation measurements for Mercury Venus, Mars etc as well.

Now the math gets tough.

I'm so curious to see if gravity is C speed now that i wish i had all the data.
Anything other than C for gravity speed is going to make gravity very hard to explain.

SpaceNut · 2005-11-30 15:25:07

The math maybe tough to process but the data collection would probably take about a century to get all the combinations for measurements.

chat · 2005-12-01 04:40:09

SpaceNut,

I wonder if we could get a crude measurement from the moon tide.
8/10th of a second isn't much to play with, but it at least would tell us if its worth the effort to measure the rest.

It shouldn't be to tough to locate exact high points on the moon tide and true and light positions of the moon.

Other than that i will have to clone myself a few times if i expect to live see a result

SpaceNut · 2005-12-01 06:13:19

I wonder if a large enough area of water that is waveless is available to make such measurements. This assumes that the gravity wave is some what focused and not disfused or spread out over a large area.

chat · 2005-12-02 04:20:39

SpaceNut,

Not sure if a sufficient sized body of water exists for a good measurement.
Even the great lakes on a calm windless night are only quiet in an area of maybe 50km.

Another way we might get a measure is any gravity assist spacecraft flyby of one of the planets.
Knowing at what time point for them and we should be able to get the same sort of true and light positions also.

Geo satellites might also be able to measure the gravitational tug as each body passes by in each earth day.

Got to be an easy measure somewhere.

chat · 2005-12-06 04:39:23

SpaceNut,

I've been doing a few calculations on flyby positions and actual planet positions.
Although the data isn't really precise enough, it seems to show that spacecraft are not getting a L speed gravity assist in a flyby.

From the data i looked at it looks like the true position is the true assist.
Gravity FTL. ?

To verify it we would need an atomic clock on a flyby vehicle and exact center locations and light positions of the flyby object.

Anyone have an easier idea to make a precise gravity speed measure?

SpaceNut · 2005-12-06 06:44:24

Well not sure but it appears very possible that it can be done as indicated by this article. While it is not quite the same the techniques of measurement does not change all that much.

Antarctic tide gravity map is produced

Another thought would be to monitor geo sat orbit by laser ranging its distance when forces are not present. Then measure when gravity should be in alignment for its orbit being alongated towards the induced force.

edit
Here is the Nasa link:
NASA Satellites Yield Best-Ever Antarctic Maps

chat · 2005-12-06 19:19:43

SpaceNut,

Very interesting info on Antarctic tide gravity map.
I will have to bug some people there and see if they are interested in sharing info

Wonder if we could measure the radio signal delay on most of the geo satellites when no influences are present, and when they are?

That could be done on any TV or communications sat.
Then just correlate the when and where on small differences in reception times.

reddragon · 2006-01-03 16:37:36

Does Jupiter have any measurable affect on the tides that can be distinguished from the rest of the tide? I believe the moon is the main cause of tides on Earth. Also, is the speed of gravitational interaction not known? I'd always kind of assumed it was lightspeed I guess, but I'm not sure I had any reason for that. I wouldn't be surprised if there's already been some experiment to measue it, though.

SpaceNut · 2006-01-04 06:15:23

I came across this yesterday and wondered if we could infer from some additional data collection the speed of gravity from this articles quote. More outrageous waste

A three-stage Atlas rocket will accelerate New Horizons to 8 miles per second making it the fastest spacecraft ever. But even with that speed record, it will take New Horizons a decade to reach Pluto. If New Horizons launches between Jan. 17 and Feb. 1, it will pass Jupiter in 2007 – using that giant planet's gravitational field to pick up extra speed – and encounter Pluto in 2015.
But if the spacecraft launches between Feb. 2 and Feb. 14, it will have to take a slower route to Pluto without the Jupiter flyby, arriving between 2016 and 2020. After mid-February it will not be possible to launch New Horizons for another year.
New Horizons will be racing Pluto's winter, when the temperature drops to minus 380 degrees.

If we turn hubble and other space telescope into the first speed trap to capture the times and placement of the probe before and after the slingshot menuever. Plus gots some real distance measurtements to the planet from the probe to the probe from its surface could we then calculate based on the arc what force and speed gravity does exert.

chat · 2006-01-04 07:03:33

reddragon,

It was the same for me about assuming the speed of gravity until i got this notion about measuring it.

Even the moon tide seems to be pointing at the moon and not at the moons position at L speed.

I've stumbled across 2 locations that could help with detailed data since i started searching, but neither will or can respond for my request for the detailed data needed to place a time on things.

Little to no work i can find seems to have been done on gravitation influence speed calculations.
It might be an idea so simple no one has given it a thought.

Jupiter does have a gravitational effect on us, but a small one that requires very precise measurements to pin down.
The moon is almost to close to get a reliable measure even with very precise measure, earth and moon both move so calculating from it would be very difficult.

Measuring a moving body like Spacenut suggests might be a key to getting some details of what is pulling from where at what time.

Very precise measures of a few geo satellites, measuring the time shift in signal return could probably pin down a speed measure.
Then just add the true and Lspeed planetary location data to get a result.
Keep in mind though that a geo sattelite might move no more than 1/10" on a full gravitation tug of a few aligned planets, a few geo sattelites will be needed to be precise.

SpaceNut · 2007-07-31 20:53:47

In addition you would also need a time when Jupiter did not exert any tidal forces as well as for the moon or mars to prove out the speed or force amounts.

Wow even surprized myself that I remembered the thread was about gravity speed measurement.

Measuring sea level rise from space

Melvin · 2007-08-22 23:25:11

The math maybe tough to process but the data collection would probably take about a century to get all the combinations for measurements.

Yeah thats true indeed.Well Online Math tutor at

Mental Math adds to mathematics basics

which support the combinations for measurements.

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#1 2005-11-30 04:08:11

Re: Gravity speed experiment

#2 2005-11-30 04:36:00

Re: Gravity speed experiment

#3 2005-11-30 06:34:50

Re: Gravity speed experiment

#4 2005-11-30 06:38:47

Re: Gravity speed experiment

#5 2005-11-30 07:30:51

Re: Gravity speed experiment

#6 2005-11-30 09:14:20

Re: Gravity speed experiment

#7 2005-11-30 15:14:52

Re: Gravity speed experiment

#8 2005-11-30 15:25:07

Re: Gravity speed experiment

#9 2005-12-01 04:40:09

Re: Gravity speed experiment

#10 2005-12-01 06:13:19

Re: Gravity speed experiment

#11 2005-12-02 04:20:39

Re: Gravity speed experiment

#12 2005-12-06 04:39:23

Re: Gravity speed experiment

#13 2005-12-06 06:44:24

Re: Gravity speed experiment

#14 2005-12-06 19:19:43

Re: Gravity speed experiment

#15 2006-01-03 16:37:36

Re: Gravity speed experiment

#16 2006-01-04 06:15:23

Re: Gravity speed experiment

#17 2006-01-04 07:03:33

Re: Gravity speed experiment

#18 2007-07-31 20:53:47

Re: Gravity speed experiment

#19 2007-08-22 23:25:11

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