Path: ...!news-out.netnews.com!postmaster.netnews.com!us13.netnews.com!not-for-mail X-Trace: DXC==el6jZNOVhjRM5UmN4`aS\N``?HA18h:n8`>X\Y[G[2@2nSQ\GNh[D=\jXKD5`g3Edei>Ca2o_^63Ia X-Complaints-To: support@frugalusenet.com Date: Mon, 22 Apr 2024 16:44:35 -0400 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: anti-gravity? [OT] Newsgroups: sci.electronics.design References: <1qsepmy.1igbph81ebujn0N%liz@poppyrecords.invalid.invalid> Content-Language: en-US From: bitrex In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Lines: 96 Message-ID: <6626cc33$0$2422125$882e4bbb@reader.netnews.com> NNTP-Posting-Host: 127.0.0.1 X-Trace: 1713818675 reader.netnews.com 2422125 127.0.0.1:37449 Bytes: 5357 On 4/22/2024 12:11 PM, 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? > > (That gets philosophical, namely why does mathematics define the > world?) > I don't think we know for sure that conservation of energy holds on a cosmological scale, since we don't know for sure the global topology of the Universe. In a hypothetical Universe that's topologically flat and unbounded there's still the boundary condition at infinity to be considered, which I think could in principle be a singularity sort of like a "white hole", anything could come flying in and conservation of energy can't hold exactly.