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Groups > sci.physics > #592893
| From | bartekltg <bartekltg@gmail.com> |
|---|---|
| Newsgroups | sci.physics |
| Subject | Re: Gravity Force Has No Speed |
| Date | 2016-08-12 14:01 +0200 |
| Organization | ATMAN - ATM S.A. |
| Message-ID | <nokdr1$dof$1@node2.news.atman.pl> (permalink) |
| References | (1 earlier) <fd20b3bf-1cb2-4f9f-8b9f-9ea8ed185b06@googlegroups.com> <bf6efea1-8241-4792-bc74-7181b333bae2@googlegroups.com> <bksnqbpl9j0f0jmlk5utup80o8q522es96@4ax.com> <noht3d$89l$1@node1.news.atman.pl> <st5rqbp2u9mr7uqabugj7ip7isladq05su@4ax.com> |
On 12.08.2016 11:48, Michael J. Strickland wrote: > On Thu, 11 Aug 2016 15:03:40 +0200, bartekltg <bartekltg@gmail.com> > wrote: > >> On 11.08.2016 10:30, Michael J. Strickland wrote: >>> On Wed, 10 Aug 2016 12:57:53 -0700 (PDT), "reber g=emc^2" >>> <herbertglazier0@gmail.com> wrote: >>> >>>> On Wednesday, July 27, 2016 at 10:44:07 AM UTC-7, reber g=emc^2 wrote: >>>>> On Wednesday, July 20, 2016 at 12:16:49 PM UTC-7, reber g=emc^2 wrote: >>>>>> No lab is trying to measure the speed of gravity for that reason.Einstein said it was at c.He had no reason to think that.I have a reason to think its force is always there,and I have two good reasons as I type this for this thinking.Might think of more ways to back up this claim too.Treb I know will help. TreBert >>> >>> I've thought of an experiment to test the speed of gravity. When Venus >>> transits the sun, we can assume the sun is a fixed background and the >>> light travel time from Venus is about 140 seconds so the reduced >>> gravitational force at the earth's surface from Venus should occur >>> about 140 seconds before we observe the actual alignment if gravity is >>> instantaneous but in sync with the apparent alignment if it propagates >>> at the speed of light. >>> >>> Venus (in perfect alignment) should reduce earth's measured surface >>> gravity (at noon) by -1.841e-7 Newtons (or 0.184 micro Newtons). I >> >> Why? > > Why is the earth's gravity reduced when Venus is aligned with us? Yes. More precisely, why you expect a big difference between the two situation: gravity is instant and gravity propagate as light. > Venus's gravity pulling us off the surface of the earth reaches its > maximum when it is most nearly overhead at its zenith (highpoint in > the sky). This gravity reduces the amount of the downward pull of > earth's gravity on us. Agree. > This is the reason ocean (and land) tidal bulges are maximum when the > moon is most nearly aligned with us at its zenith. We could use the > moon but it only gives us a 1.28 second delta between the time it > reaches its zenith and its gravitational effect on us maximizes. > I just did the math (again) last night and the numbers may be off but > the effect, while miniscule, should be measurable these days. OK. I was afraid you have in mind "shielding" or some other undetected effects. You want to observe gravitational acceleration during Venus transit and check, if the extreme of the force is shifted relative to the centre of transit (when Sun and Venus are pulling together)? Is sound quite difficult (other celestial bodies effect us too, during two minutes Earth will rotate, so Zenith is not the best reference point), but on the first look doable... But on the closer look I see three major problems with this:/ - "trigonometry". We do not have to compare "there is gravitational Influenfe from Venus" to "there is not" but "Venus is Here" to "Venus is where is should be in 140s". Sun's angular diameter is ~32arc minutes, transit took 6.5hours, so 140seconds give us displacement of 0.19 arc minutes or 5.6 *10^-5 radians. Venus do not "appear". Is slightly moves. The whole Venus influence is http://www.wolframalpha.com/input/?i=grawitation+constant+*+Venus++mass++%2F+(AU-Venus+orbital+radius+)%5E2 1.9 *10^-7 N/kg (you have wrote 1.841e-7, so it is the same) And chenge in the force is: 1.9 *10^-7 = 1.9 *10^-7 N/kg we get only 1 *10 ^ -11 N/kg (or m/s^2) I not sure we can measure this. But this is perpendicular (to the line Earth-Sun) force. If you want to measure drop in the force in zenith direction, it drop like cos(alpha) ~= 1- alpha^2/2 3 *10^-16 Newtons/kg. It will do not work. Still, we can try to attack the 'perpendicular' part of the change in force, and do some tricks to get rid of influence of other bodies. Then there is the second problem: -"free-falling". Earth is not fixed in spaces. It flies like gravity tells it. The same gravity we want to measure. If you are on very small planet, or (better) a spaceship, and you flight on low Earth orbit, gravitational force acting on you and your ship is still almost like on earth 8.95 m/s^2 on 300km orbit. But you and your instruments do not detect anything. Earth gravitation is compensated by inertial forces. (this is the whole idea of space stations;-)) (I do not try to say hare that acceleration and gravitation is the same. Only that we can detect the difference:) The same works with Earth when it travel in other bodies' gravitation. In the centre of Earth (luckily to our example it is both geometric centre and centre of mass) you will not detect influence of other bodies. Sun acts 0.00593m/s^2 on you, but also on the Earth as a whole, and Earth is accelerating 0.00593m/s^2, so in your room in Earth core there is no effect. Accelerometers displays 0. Tides are "second order" effects. On an ocean closer to the Moon(or Sun), Moon acts with stronger force. The difference between this force and mean acceleration of whole planet is a net force that cause tides. So our detectors do not feel G * Venus mass / distance^2 = 1.9 *10^-7 N/kg If feels G * Venus mass / (distance-earth radius)^2 - G * Venus mass / distance^2 = 2 (G Venus mass) earth radius / distance^3 + O (lesser terms) http://www.wolframalpha.com/input/?i=gravitation+constant+*+Venus++mass++%2F+(AU-Venus+orbital+radius+)%5E3+*+2+earth+radius 5.8 *10^-11. 3250 times less. From every results from the first "problem" we have to cut three and a half of digits. It will do not work:( We do not have means to measure that weak changes in forces. - The last problem is more theoretical. We want compare two hipotesis, graviti is instant and it is slow (like c). But we do not compare it to every possible theory with slow gravity. We do not even compare it to the better ones! We construct something like 'fuid gravity' Laplace considered... and proved it have to be instant:) https://en.wikipedia.org/wiki/Speed_of_gravity#Laplace But this mean nothing. We know that slow gravitation do not work like Laplace assumed. We should take for example general relativity and use it as a model of 'slow gravity' case. Ant there https://en.wikipedia.org/wiki/Einstein%E2%80%93Infeld%E2%80%93Hoffmann_equations all but one parts of the force act in tke lines between _current_ positions of the bodies. So like in the instant gravity. The last term describe force acting in the line of acceleration of the second body, not the velocity. So even if you can perform that experiment, and get results, still instant gravitiation and GR give us almost the same predictions. WOW, it was long. TLDR: -Venus do not appears suddenly. Is only slightly moves. The force change during the 140s period is not 1.9 *10^-7 but this number multiply by (in the best scenerio) sinus of quite small angle. -Earth is not fixed in space. If something attract us (an accelerometer) it attract whole Earth (and base of the accelerometer is fixed to it). Accelerometer (and water in tides) on the surface do not feel GM/r^2 (relatively to Earth) it feels 2GM earth_radius /r^3 (r=distance, M = Venus mass. ) That is 5.8 *10^-11 (and this have to be multiply by sinus of mentioned before small angle) -To get prediction of how delayed gravity works you have used very simple toy theory. Theory that we know do not works. If we get better one (General Relativity) this sort of differences between both models disappear. This kind of experiment can't distinct between GR and instant Newtonian gravity. bartekltg
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Gravity Force Has No Speed "reber g=emc^2" <herbertglazier0@gmail.com> - 2016-07-20 12:16 -0700
Re: Gravity Force Has No Speed mapou001@gmail.com - 2016-07-20 13:52 -0700
Re: Gravity Force Has No Speed Odd Bodkin <bodkinodd@gmail.com> - 2016-07-20 16:47 -0500
Re: Gravity Force Has No Speed HVAC <mr.hvac@gmail.com> - 2016-07-20 15:08 -0700
Re: Gravity Force Has No Speed benj <benj@nobody.net> - 2016-07-20 20:34 -0400
Re: Gravity Force Has No Speed HVAC <mr.hvac@gmail.com> - 2016-07-21 05:58 -0700
Re: Gravity Force Has No Speed mapou001@gmail.com - 2016-07-20 17:57 -0700
Re: Re: Gravity Force Has No Speed Michael J. Strickland <michael06582@comcast.net> - 2016-07-21 02:52 -0400
Re: Re: Gravity Force Has No Speed mapou001@gmail.com - 2016-07-21 09:04 -0700
Re: Gravity Force Has No Speed Odd Bodkin <bodkinodd@gmail.com> - 2016-07-21 11:34 -0500
Re: Gravity Force Has No Speed mapou001@gmail.com - 2016-07-21 10:00 -0700
Re: Gravity Force Has No Speed Odd Bodkin <bodkinodd@gmail.com> - 2016-07-21 12:09 -0500
Re: Re: Re: Gravity Force Has No Speed Michael J. Strickland <michael06582@comcast.net> - 2016-07-22 02:05 -0400
Re: Re: Re: Gravity Force Has No Speed mapou001@gmail.com - 2016-07-22 07:50 -0700
Re: Gravity Force Has No Speed Odd Bodkin <bodkinodd@gmail.com> - 2016-07-22 10:03 -0500
Re: Gravity Force Has No Speed mapou001@gmail.com - 2016-07-22 08:07 -0700
Re: Gravity Force Has No Speed Odd Bodkin <bodkinodd@gmail.com> - 2016-07-22 10:53 -0500
Re: Gravity Force Has No Speed mapou001@gmail.com - 2016-07-22 09:03 -0700
Re: Re: Re: Re: Gravity Force Has No Speed Michael J. Strickland <michael06582@comcast.net> - 2016-07-23 04:52 -0400
Re: Re: Re: Re: Gravity Force Has No Speed mapou001@gmail.com - 2016-07-23 14:48 -0700
Re: Re: Re: Re: Re: Gravity Force Has No Speed Michael J. Strickland <michael06582@comcast.net> - 2016-08-08 15:43 -0400
Re: Re: Gravity Force Has No Speed Michael J. Strickland <michael06582@comcast.net> - 2016-07-21 02:56 -0400
Re: Re: Gravity Force Has No Speed mapou001@gmail.com - 2016-07-21 09:19 -0700
Re: Gravity Force Has No Speed Odd Bodkin <bodkinodd@gmail.com> - 2016-07-21 11:37 -0500
Re: Gravity Force Has No Speed mapou001@gmail.com - 2016-07-21 10:01 -0700
Re: Gravity Force Has No Speed Odd Bodkin <bodkinodd@gmail.com> - 2016-07-21 12:11 -0500
Re: Gravity Force Has No Speed mapou001@gmail.com - 2016-07-21 11:33 -0700
Re: Re: Re: Gravity Force Has No Speed Michael J. Strickland <michael06582@comcast.net> - 2016-07-22 01:55 -0400
Re: Re: Re: Gravity Force Has No Speed mapou001@gmail.com - 2016-07-22 09:01 -0700
Re: Re: Re: Gravity Force Has No Speed john <johnsefton288@gmail.com> - 2016-07-22 09:15 -0700
Re: Re: Re: Gravity Force Has No Speed mapou001@gmail.com - 2016-07-22 09:37 -0700
Re: Gravity Force Has No Speed Odd Bodkin <bodkinodd@gmail.com> - 2016-07-22 12:18 -0500
Re: Gravity Force Has No Speed mapou001@gmail.com - 2016-07-22 10:50 -0700
Re: Gravity Force Has No Speed Odd Bodkin <bodkinodd@gmail.com> - 2016-07-22 13:42 -0500
Re: Gravity Force Has No Speed mapou001@gmail.com - 2016-07-22 11:44 -0700
Re: Gravity Force Has No Speed Odd Bodkin <bodkinodd@gmail.com> - 2016-07-22 13:52 -0500
Re: Gravity Force Has No Speed mapou001@gmail.com - 2016-07-22 11:57 -0700
Re: Gravity Force Has No Speed Odd Bodkin <bodkinodd@gmail.com> - 2016-07-22 14:14 -0500
Re: Gravity Force Has No Speed Odd Bodkin <bodkinodd@gmail.com> - 2016-07-22 14:32 -0500
Re: Gravity Force Has No Speed mapou001@gmail.com - 2016-07-22 13:00 -0700
Re: Gravity Force Has No Speed Odd Bodkin <bodkinodd@gmail.com> - 2016-07-22 17:02 -0500
Re: Gravity Force Has No Speed mapou001@gmail.com - 2016-07-22 15:30 -0700
Re: Gravity Force Has No Speed Odd Bodkin <bodkinodd@gmail.com> - 2016-07-23 10:49 -0500
Re: Gravity Force Has No Speed mapou001@gmail.com - 2016-07-23 09:31 -0700
Re: Gravity Force Has No Speed Odd Bodkin <bodkinodd@gmail.com> - 2016-07-23 11:39 -0500
Re: Gravity Force Has No Speed mapou001@gmail.com - 2016-07-23 16:53 -0700
Re: Gravity Force Has No Speed Odd Bodkin <bodkinodd@gmail.com> - 2016-07-24 15:13 -0500
Re: Gravity Force Has No Speed mapou001@gmail.com - 2016-07-24 14:19 -0700
Re: Gravity Force Has No Speed Odd Bodkin <bodkinodd@gmail.com> - 2016-07-25 07:58 -0500
Re: Gravity Force Has No Speed mapou001@gmail.com - 2016-07-25 13:08 -0700
Re: Gravity Force Has No Speed Odd Bodkin <bodkinodd@gmail.com> - 2016-07-25 15:56 -0500
Re: Gravity Force Has No Speed mapou001@gmail.com - 2016-07-25 14:14 -0700
Re: Gravity Force Has No Speed benj <benj@nobody.net> - 2016-07-22 17:01 -0400
Re: Gravity Force Has No Speed Odd Bodkin <bodkinodd@gmail.com> - 2016-07-22 12:15 -0500
Re: Gravity Force Has No Speed mapou001@gmail.com - 2016-07-22 10:48 -0700
Re: Gravity Force Has No Speed Odd Bodkin <bodkinodd@gmail.com> - 2016-07-22 13:36 -0500
Re: Gravity Force Has No Speed mapou001@gmail.com - 2016-07-22 11:37 -0700
Re: Gravity Force Has No Speed Odd Bodkin <bodkinodd@gmail.com> - 2016-07-22 13:51 -0500
Re: Re: Re: Re: Gravity Force Has No Speed Michael J. Strickland <michael06582@comcast.net> - 2016-07-23 05:09 -0400
Electric field (was: Re: Re: Gravity Force Has No Speed) Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2016-07-25 07:43 +0200
Re: Electric field (was: Re: Re: Gravity Force Has No Speed) mapou001@gmail.com - 2016-07-24 23:12 -0700
Re: Electric field Odd Bodkin <bodkinodd@gmail.com> - 2016-07-25 08:26 -0500
Re: Electric field mapou001@gmail.com - 2016-07-25 13:08 -0700
Re: Electric field Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2016-07-25 18:43 +0200
Re: Electric field mapou001@gmail.com - 2016-07-25 12:16 -0700
Re: Electric field Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2016-07-25 22:27 +0200
Re: Electric field mapou001@gmail.com - 2016-07-25 18:02 -0700
Re: Electric field Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2016-07-26 07:14 +0200
Re: Electric field Odd Bodkin <bodkinodd@gmail.com> - 2016-07-25 15:51 -0500
Re: Gravity Force Has No Speed "reber g=emc^2" <herbertglazier0@gmail.com> - 2016-07-21 09:36 -0700
Re: Gravity Force Has No Speed "reber g=emc^2" <herbertglazier0@gmail.com> - 2016-07-22 17:59 -0700
Re: Gravity Force Has No Speed benj <benj@nobody.net> - 2016-07-23 17:37 -0400
Re: Gravity Force Has No Speed "reber g=emc^2" <herbertglazier0@gmail.com> - 2016-07-27 10:44 -0700
Re: Gravity Force Has No Speed "reber g=emc^2" <herbertglazier0@gmail.com> - 2016-08-10 12:57 -0700
Re: Gravity Force Has No Speed "hanson" <hanson@quick.net> - 2016-08-10 16:38 -0700
Re: Re: Gravity Force Has No Speed Michael J. Strickland <michael06582@comcast.net> - 2016-08-11 04:30 -0400
Re: Gravity Force Has No Speed bartekltg <bartekltg@gmail.com> - 2016-08-11 15:03 +0200
Re: Re: Gravity Force Has No Speed Michael J. Strickland <michael06582@comcast.net> - 2016-08-12 05:48 -0400
Re: Gravity Force Has No Speed bartekltg <bartekltg@gmail.com> - 2016-08-12 14:01 +0200
Re: Gravity Force Has No Speed LIGO Fraud Investigator <mapou001@gmail.com> - 2016-08-12 09:16 -0700
Re: Gravity Force Has No Speed bartekltg <bartekltg@gmail.com> - 2016-08-13 12:40 +0200
Re: Gravity Force Has No Speed LIGO Fraud Investigator <mapou001@gmail.com> - 2016-08-14 12:30 -0700
Re: Gravity Force Has No Speed bartekltg <bartekltg@gmail.com> - 2016-08-10 23:11 +0200
Re: Gravity Force Has No Speed LIGO Fraud Investigator <mapou001@gmail.com> - 2016-08-10 15:47 -0700
Re: Gravity Force Has No Speed bartekltg <bartekltg@gmail.com> - 2016-08-11 15:28 +0200
Re: Gravity Force Has No Speed LIGO Fraud Investigator <mapou001@gmail.com> - 2016-08-14 12:23 -0700
Re: Gravity Force Has No Speed Odd Bodkin <bodkinodd@gmail.com> - 2016-08-15 08:27 -0500
Re: Gravity Force Has No Speed Odd Bodkin <bodkinodd@gmail.com> - 2016-08-11 09:17 -0500
Re: Gravity Force Has No Speed LIGO Fraud Investigator <mapou001@gmail.com> - 2016-08-12 12:53 -0700
Re: Gravity Force Has No Speed bartekltg <bartekltg@gmail.com> - 2016-08-13 11:23 +0200
Re: Gravity Force Has No Speed LIGO Fraud Investigator <mapou001@gmail.com> - 2016-08-14 12:24 -0700
Re: Gravity Force Has No Speed Odd Bodkin <bodkinodd@gmail.com> - 2016-08-15 08:28 -0500
Re: Gravity Force Has No Speed LIGO Fraud Investigator <mapou001@gmail.com> - 2016-08-15 11:38 -0700
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