That damn gravity measurement... - Page 1
Forum section: electronics / general

author: GlennSprigg
author_rank: Super Contributor
timestamp: August 30, 2020, 01:51:42 pm
content: 'MY' theory is that 'Gravity' is like the Kinetic/Potential energy of the proverbial 'Big-Bang'!!We agonize over where it all started. Let's look at a 'Simple' physical construction, where there are two boards, held at adistance between them. To all intensive purposes, between those two boards, there are two springs attached between them.ONE has NO spring tension, and the OTHER has a 'force' trying to pull them together. All this seems perfectly feasible, BUT imaginesome external device/meter that you 'point' at it, or wave it around, that can measure/detect these forces?? You can't.It's at(within) an atomic/molecular level. Your 'sensors' need to be within the atomic structure!! To my mind, it's LIKE that, whenpeople keep trying to 'measure/detect' Gravity Waves. It's a lost cause. I 'think' that possibly Gravity can only exist, as we knowit & imagine it, is because originally, ALL matter/energy was initially emanating from that single point at creation...Imagine the Conundrum of 2 objects/matter 'materializing' in Space. Would the 'force' between them be instantaneous??, ormaybe have to travel at the "speed of light" or something first? Hang on, it's said that energy can not be created or destroyed, butonly transformed from one form to another or from one object to another... Yep. I propose also that matter is but a 'form' of energy!'Matter' has been converted to energy as in E = MC2 in nuclear explosions. And vast amounts of Energy have, in particle acceleratorsor atomic 'splitters' resulted in the re-creation of matter (Protons) as well as other 'particles'. So if matter is a form of energy, then it'snot a big leap to imagine the 'Big-Bang' (the source of it all!) to change how we 'try' to compartmentalize 'Gravity'. OK I'm done...

author: ChristofferB
author_rank: Frequent Contributor
timestamp: August 30, 2020, 02:12:39 pm
content: Expressing matter in terms of energy and vice versa is completely physically justified and has been routinely exploited for a century. I have no idea what you're trying to say about gravity however, I'm afraid.

author: Domagoj T
author_rank: Frequent Contributor
timestamp: August 30, 2020, 02:12:47 pm
content: Why do you capitalize and put random words between apostrophes? What is the meaning of that?Anyway...QuoteIntents and purposes...What do you need the first spring for, then? As for the second one, crude and not quite accurate analogy, but ok for lay discussion. Anyway, we can point or wave around a device that will measurethat force (well, maybe not a gravitational pull of a board, but something larger). Gravimeters are devices that measure gravitational pull directly.QuoteGo to your bathroom scale. Is that subatomic device? No. Effects of gravity are most certainly evident on scales much larger than subatomic.QuoteGravity waves have been detected and measured repeatedly. Measurements are in line with theoretical calculations. Far from lost cause.QuoteAny reason why you think that?QuoteIt would travel at the speed of light. This was also measured and observed.QuoteI don't see how is this related to your previous sentence, but in any case, you're not the first to propose that. Energy is routinely transformed into matter (actually matter + as much antimatter) in particle accelerators.QuoteThat is a non sequitur.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: August 30, 2020, 03:12:54 pm
content: Quote from: GlennSprigg on August 30, 2020, 01:51:42 pmThis will require quite a lot of explanation (on your part). For my part, let me explain why:There's no energy associated with the Big Bang; or rather it's not so meaningful to speak of, I think. The apparent expansion or contraction of the universe over time, is simply a side effect of a universe having a more-or-less uniform mass-energy distribution:https://en.wikipedia.org/wiki/Friedmann%E2%80%93Lema%C3%AEtre%E2%80%93Robertson%E2%80%93Walker_metricEnergy is conserved for objects in space, but space-time as a whole doesn't need to conserve it.So, something being "like" the kinetic or potential energy of a spacetime, is at best analogous. One must define those terms, because they don't apply in the normal way to a spacetime.QuoteWell no, these forces* can be measured as surely as any other acceleration can be. We even carry around accelerometers in our pockets these days!*A gravitational field is an acceleration field. Force is only meaningful when a mass is given (F = ma).If you're trying to measure the gravitational field of a "board" and are having bad luck just because your boards aren't the size of minor asteroids, well, that's your problem -- that's experimental error, not fundamental physics! (These measurements have indeed been done, with economically sized masses; the error bars aren't fantastic, but the confidence level is quite good nonetheless.)Tim

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: August 30, 2020, 04:20:27 pm
content: page 22https://apps.dtic.mil/dtic/tr/fulltext/u2/a093780.pdfI always wanted to build one since the concept seems simple enough.... but it isn't. I don't have the money or skills to pull it off either. At one point I thought I could get all the precision parts needed from old hard drives but even then the measurement itself seems tricky at best.

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: August 30, 2020, 09:01:56 pm
content: Quote from: Domagoj T on August 30, 2020, 02:12:47 pmThat's "his" Style, man.

author: TimFox
author_rank: Super Contributor
timestamp: August 30, 2020, 10:00:29 pm
content: Here's a modern example of the classic Cavendish measurement of the force between two masses:https://sciencedemonstrations.fas.harvard.edu/presentations/cavendish-experiment

author: bson
author_rank: Unknown
timestamp: August 31, 2020, 12:42:01 am
content: Gravitational waves have already been detected by LIGO. They see one on average every two months, a total of 11 right now.

author: GlennSprigg
author_rank: Super Contributor
timestamp: September 02, 2020, 12:52:49 pm
content: Quote from: Alex Eisenhut on August 30, 2020, 09:01:56 pmYep.Again, the only intention is emphasis on certain key words, unrelated to specific Grammar, for brief text.Eg. If I said, "People think of 'Gravity' in different ways", it's suggestive (my opinion) that we don't know what it really is.Regarding other responses though, I understand the known processes & maths used to measure what we call Gravity as we know it,however, what I was really talking about is the actualsubstance(for the want of a better word) that encompasses it!Domagoj Tsaid in answer to my proposition about two masses materializing in space, and the Force being instantaneous or not...He said, "It would travel at the speed of light". So, is he saying that if the two masses appeared in space at the distance from our Sunto Earth, then for 499 Seconds nothing would happen, andthensuddenly start moving together?But my pondering, (with limited time/space/place for a better analogy), was simply about the actualstuffof Gravity!It was not to cause multiple side issues of offense. Have a good day/night to all !!

author: Rick Law
author_rank: Super Contributor
timestamp: September 05, 2020, 12:56:47 am
content: Quote from: GlennSprigg on August 30, 2020, 01:51:42 pmExpressing it as "'Gravity'is likethe Kinetic/Potential energy" is incorrect. One should think of mass as the total energy content.Kinetic/Potential energyisMass, and Mass makes Gravity. So Kinetic/Potential energy make (additional) Gravity.To clarify the point, I will use a mechanical music box. A mechanical music box will have greater mass after it was wounded up as compared to before it was wounded up - The wound up spring has greater mass due to its greater energy.I don't know how to prove that without a million dollar mass/weight scale, so I will just quote Einstein, "...we are led to the more general conclusion that- The mass of a body is a measure of its energy-content; if the energy changes by L, the mass changes in the same sense by L/9×1020, the energy being measured in ergs, and the mass in grammes.- (other points not quoted - they are not pertinent to the discussion here)..."Quoted from the English translation of Einstein's Sep 27, 1905 paper "DOES THE INERTIA OF A BODY DEPEND UPON ITS ENERGY-CONTENT?"https://www.fourmilab.ch/etexts/einstein/E_mc2/e_mc2.pdfQuote from: Domagoj T on August 30, 2020, 02:12:47 pmActually working out Gravity at the subatomic level is a problem. Relativity doesn't work with Quantum Mechanics, so we will have a hard time designing any sensor in the sub-atomic level and have the sensor being gravity related.

author: Brumby
author_rank: Unknown
timestamp: September 05, 2020, 04:37:57 am
content: Quote from: GlennSprigg on September 02, 2020, 12:52:49 pmHe has become a little more subdued since first posting, but it's just how he rolls. Indeed, it is his style.

author: GlennSprigg
author_rank: Super Contributor
timestamp: September 05, 2020, 12:36:57 pm
content: Quote from: Brumby on September 05, 2020, 04:37:57 amHi Brumby. Yea, I think I've mellowed it a bit, haha... BTW I don't have a problem with Alex saying... "That's "his" Style, man", in fact I likeit! However, notice how he used quotes around the word "his". Maybe he was taking the piss, but that's alright.Lately, I've been putting some key word or questionable word in italics, but it has the same intention!