Path: ...!3.eu.feeder.erje.net!feeder.erje.net!eternal-september.org!feeder3.eternal-september.org!news.eternal-september.org!.POSTED!not-for-mail From: Bill Sloman Newsgroups: sci.electronics.design Subject: Re: anti-gravity? [OT] Date: Tue, 23 Apr 2024 18:59:21 +1000 Organization: A noiseless patient Spider Lines: 97 Message-ID: References: <1qsepmy.1igbph81ebujn0N%liz@poppyrecords.invalid.invalid> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Injection-Date: Tue, 23 Apr 2024 10:59:25 +0200 (CEST) Injection-Info: dont-email.me; posting-host="056ab92a209c73825bfec3fc22a8b391"; logging-data="1622404"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX1+nTRhzs3ZhAT7v5GxsLe2r+VpVWM4t2tE=" User-Agent: Mozilla Thunderbird Cancel-Lock: sha1:p1k/ku7+QeL4I9dEyOrp/dovrCc= In-Reply-To: Content-Language: en-US Bytes: 5376 On 23/04/2024 2:11 am, John Larkin wrote: > On Mon, 22 Apr 2024 15:00:21 -0000 (UTC), Phil Hobbs > wrote: > >> Liz Tuddenham wrote: >>> jim whitby wrote: >>> >>>> Looking for opinion of persons better educatrd than myself. >>>> >>>> >>> that-physics-says-shouldnt-work-just-produced-enough-thrust-to-defeat- >>>> earths-gravity/> >>> >>> Has anyone come across the alternative theory of gravity which I first >>> heard of from P.G.A.H. Voigt? >>> >>> It suggests that the current theory of gravity is rather like the idea >>> we used to have that there was force 'due to vacuum', rather than air >>> pressure. It proposes that the real cause of the gravitational effects >>> we observe is not an attraction but a pressure. >>> >>> The concept is that a force acts on all bodies equally in all dirctions. >>> When two bodies with mass approach each other, each shields the other >>> from some of this force and the remaining forces propel the bodies >>> towards each other. >>> >>> I don't know how it would be possible to test whether this was in fact >>> how 'gravity' worked and whether it was possible to differentiate it >>> from the current theory, as the two would appear to have identical >>> observed effects. >>> >>> >> >> Of course little things like the equality of inertial and gravitational >> mass (so that objects of different density fall at the same speed) don’t >> fit easily into such a picture. >> >> Also, the rate at which the hypothetical particles collide with matter has >> to be extremely large in order to work with very dense matter, such as free >> neutrons. >> >> Neutrons have been observed to follow Newtonian gravity to very high >> accuracy in the lab. >> >> And then there’s the complete absence of Brownian motion in free particles. >> With some huge flux of particles carrying the sort of momentum that would >> be required to account for the gravitational motion of free neutrons, the >> resulting fluctuations would be very visible. >> >> Besides, if the particles bounce off the gravitating objects, their >> velocity distribution will change as a consequence. (Some of them will >> rattle around between them, going faster and faster as the objects get >> closer.) Thus there will be a wake effect, like a small plane taking off >> right after an A380. No such effects are observed. >> >> Not to pile on, or at least not as much as the notion deserves, but if >> relativity is completely wrong, then there is only one velocity in a given >> reference frame for which the drag force of such a particle ensemble is >> zero. >> >> And, of course, there’s the question of the origin, distribution, and >> regulation of the momentum-carrying particles. >> >> To have any chance of avoiding even these purely classical effects, the >> particles would have to have infinite speed, zero mass, perfectly uniform >> and isotropic distribution in both position and direction, perfectly timed >> arrival at each object to make the fluctuations cancel out, and on an on. >> >> This is the luminiferous ether, on stilts. >> >> And then there are matter-wave interferometers, which work not only on >> electrons, but on neutrons and even buckyballs. They set far tighter >> limits on most of these classical effects. >> >> So no, these sorts of theories are not good candidates to explain gravity >> or other relativistic effects. >> >> Cheers >> >> Phil Hobbs > > Is there any deeper explanation for conservation of energy, and for > Newton's laws, other than that's just the way things are? No. That's what science is about. > (That gets philosophical, namely why does mathematics define the world?) The world was there first, so it defines mathematics. Mathematics is a way of describing a simpler world that is close enough to the real world to be useful. It evolved in the same way as language, and for exactly the same reason - it makes organising stuff easier. -- Bill Sloman, Sydney