Antigravity phenomena

[Asimov Pupil]

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

[ydoaPs]

hmm, gravity is always negative. hence, -9.81m/s/s. unless you change ur orientation.

[Asimov Pupil]

ah but it says NEGATIVE GRAVATATIONAL phenomena so if their both negative it is a positive phenomena no?

[ydoaPs]

or not

[Asimov Pupil]

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?

[ydoaPs]

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

[Asimov Pupil]

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.

[ydoaPs]

a meteroite would make it stronger

 

edit: 2000th post for me!

[[Tycho?]]

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)

[Asimov Pupil]

ok i will research more into this matter

 

thank you

[ydoaPs]

']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.

[Asimov Pupil]

what are higgs fields?

[ydoaPs]

they (theoretically) give particles their mass.

[ydoaPs]

http://www.sciam.com/article.cfm?chanID=sa006&articleID=000005FC-2927-12B3-A92783414B7F0000&pageNumber=1&catID=2

[DQW]

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.

[DQW]

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.

[DQW]

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.

[DQW]

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.

[ydoaPs]

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.

[J.C.MacSwell]

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.

[DQW]

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.

[ydoaPs]

o, that was in either The Elegant Universe or The Fabric of the Cosmos, both by Brian Greene

[ydoaPs]

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.

[DQW]

Thanks yourdadonapogos ! (psst : may I just call you 'pogo', for short ?)

[ydoaPs]

sure, why not? i do get a lot of 'yourdad', but whatever you want.