Asimov Pupil Posted June 28, 2005 Share Posted June 28, 2005 i have a book that discusses lunar geology and states about craters "frequently shows negative gravitational anomalies due, probably, to the subterranean pressence of the meteorite" please explain Link to comment Share on other sites More sharing options...
ydoaPs Posted June 28, 2005 Share Posted June 28, 2005 hmm, gravity is always negative. hence, -9.81m/s/s. unless you change ur orientation. Link to comment Share on other sites More sharing options...
Asimov Pupil Posted June 28, 2005 Author Share Posted June 28, 2005 ah but it says NEGATIVE GRAVATATIONAL phenomena so if their both negative it is a positive phenomena no? Link to comment Share on other sites More sharing options...
ydoaPs Posted June 28, 2005 Share Posted June 28, 2005 or not Link to comment Share on other sites More sharing options...
Asimov Pupil Posted June 28, 2005 Author Share Posted June 28, 2005 as an after thought it isn't [math]-9.81m/s^2[/math] on the moon. i forget what it is though. but you get what i mean? Link to comment Share on other sites More sharing options...
ydoaPs Posted June 28, 2005 Share Posted June 28, 2005 that was just an example. g for the moon is [imath]g=-G{\frac{M}{r^2}}[/imath] where G is the gravitational constant, M is the mass of the moon, and r is the average radius of the moon Link to comment Share on other sites More sharing options...
Asimov Pupil Posted June 28, 2005 Author Share Posted June 28, 2005 i understand and maybe they messed up their words but lets not pick apart words here. a negative gravitational phenomena sounds to me like a mass that repels instead of pulls. and the reason i say that is because they mention the meteiorite. Link to comment Share on other sites More sharing options...
ydoaPs Posted June 28, 2005 Share Posted June 28, 2005 a meteroite would make it stronger edit: 2000th post for me! Link to comment Share on other sites More sharing options...
[Tycho?] Posted June 28, 2005 Share Posted June 28, 2005 i understand and maybe they messed up their words but lets not pick apart words here. a negative gravitational phenomena sounds to me like a mass that repels instead of pulls. and the reason i say that is because they mention the meteiorite. No natural mass (actually, nothing known, and nothing theorized that I know of) can make gravity push instead of pull. Either it was written in an odd way that you just didn't get it, or your source is incorrect. Anti-gravity is totally unknown (although I'd like someone to prove me wrong on this, it would be neat even to just have the inklings of a theory) Link to comment Share on other sites More sharing options...
Asimov Pupil Posted June 28, 2005 Author Share Posted June 28, 2005 ok i will research more into this matter thank you Link to comment Share on other sites More sharing options...
ydoaPs Posted June 28, 2005 Share Posted June 28, 2005 ']No natural mass (actually' date=' nothing known, and nothing theorized that I know of) can make gravity push instead of pull. Either it was written in an odd way that you just didn't get it, or your source is incorrect. Anti-gravity is totally unknown (although I'd like someone to prove me wrong on this, it would be neat even to just have the inklings of a theory)[/quote'] higgs fields can do it if there is the right level of energy. Link to comment Share on other sites More sharing options...
Asimov Pupil Posted June 28, 2005 Author Share Posted June 28, 2005 what are higgs fields? Link to comment Share on other sites More sharing options...
ydoaPs Posted June 28, 2005 Share Posted June 28, 2005 they (theoretically) give particles their mass. Link to comment Share on other sites More sharing options...
ydoaPs Posted June 28, 2005 Share Posted June 28, 2005 http://www.sciam.com/article.cfm?chanID=sa006&articleID=000005FC-2927-12B3-A92783414B7F0000&pageNumber=1&catID=2 Link to comment Share on other sites More sharing options...
DQW Posted June 28, 2005 Share Posted June 28, 2005 i have a book that discusses lunar geology and states about craters "frequently shows negative gravitational anomalies due' date=' probably, to the subterranean pressence of the meteorite" please explain[/quote']Wow ! What a lot of idle speculation on a question that is so poorly defined. Could you please post the title and author of this book, along with more than just a part of a sentence as a quotation. The entire passage that is relevant to this statement, if posted, will allow this thread to possibly develop into something that is not a general, disordered, speculative exchange. Link to comment Share on other sites More sharing options...
DQW Posted June 28, 2005 Share Posted June 28, 2005 hmm, gravity is always negative. hence, -9.81m/s/s. unless you change ur orientation.This has nothing to do with one's orientation. It has only to do with the orientation of a co-ordinate axis along which you wish to project the gravitational field vector. And any orientation is acceptable. Link to comment Share on other sites More sharing options...
DQW Posted June 28, 2005 Share Posted June 28, 2005 higgs fields can do it if there is the right level of energy.I know little of high-energy physics. So could you please show me where in the provided link (or elsewhere), it explains this particular concept ? I am honestly curious. Link to comment Share on other sites More sharing options...
DQW Posted June 28, 2005 Share Posted June 28, 2005 I suspect that the "anomaly" (in the OP) may simply be that while the gravitational field might be expected to fall away as you climb down a giant crater, it is seen to actually increase...and perhaps this increase is, in fact, due to a large, high-density meteorite embedded beneath it. Link to comment Share on other sites More sharing options...
ydoaPs Posted June 28, 2005 Share Posted June 28, 2005 This has nothing to do with one's orientation. It has only to do with the orientation of a co-ordinate axis along which you wish to project the gravitational field vector. And any orientation is acceptable. what i meant was the direction of the gravitational field is usually "down" so it is the y axis and is negative. i did give a link for the higgs field. Link to comment Share on other sites More sharing options...
J.C.MacSwell Posted June 28, 2005 Share Posted June 28, 2005 I suspect that the "anomaly" (in the OP) may simply be that while the gravitational field might be expected to fall away as you climb down a giant crater, it is seen to actually increase...and perhaps this increase is, in fact, due to a large, high-density meteorite embedded beneath it. Or oppositely (albeit lacking gravity not antigravity) the crater itself would create an anomaly at the projected "surface" (average radius) compared to what it would be if the crater didn't exist or was filled with moon dust. Link to comment Share on other sites More sharing options...
DQW Posted June 28, 2005 Share Posted June 28, 2005 what i meant was the direction of the gravitational field is usually "down" so it is the y axis and is negative. It is negative (strictly speaking, it's component along the y-axis is negative) only if you choose the positive direction of the y-axis to point upwards. There is absolutely no reason why this is required. i did give a link for the higgs field.I did read through it . . . but did not find the part that says that the Higgs Field "can make gravity push instead of pull". But I didn't read very carefully, so I could easily have missed it. Link to comment Share on other sites More sharing options...
ydoaPs Posted June 28, 2005 Share Posted June 28, 2005 o, that was in either The Elegant Universe or The Fabric of the Cosmos, both by Brian Greene Link to comment Share on other sites More sharing options...
ydoaPs Posted June 28, 2005 Share Posted June 28, 2005 A Higgs field that has gotten caught on a plateau not only suffuses space with energy, but, of crucial importance, Guth realized that it also contributes a uniform negative pressure. In fact, he found that as far as energy and pressure are concerned, a Higgs field that's caught on a plateau has the same properties as a cosmological constant: it suffuses space with energy and negative pressure, and in exactly the same proportions as a cosmological onstant. So Guth discovered that a supercooled Higgs field does have an important effect on the expansion of space: like a cosmological constant, it exerts a repulsive gravitational force that drives space to expand.[sup']9[/sup] there you go. Link to comment Share on other sites More sharing options...
DQW Posted June 28, 2005 Share Posted June 28, 2005 Thanks yourdadonapogos ! (psst : may I just call you 'pogo', for short ?) Link to comment Share on other sites More sharing options...
ydoaPs Posted June 28, 2005 Share Posted June 28, 2005 sure, why not? i do get a lot of 'yourdad', but whatever you want. Link to comment Share on other sites More sharing options...
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