Do you believe in gravity?

[Dr.Who]

That would be the FORCE DUE TO GRAVITY -- not GRAVITY.

If that is the most technically correct answer then we could say that we have never really observed gravity at all. We have just surmised it's existence based on our observations of the force due to gravity.

 

[revolution4PAUL]

Hmm, interesting discussion. My uneducated statement on the subject is that gravity is like the wind before we knew air had mass/molecules. We can't see it but we know its there and see its effects.

We are in the infant stage of our technological advances, just think about the computers that we owned 15 years ago. There will be many more revolutionary breakthroughs, but, all in good time and at Gods speed(whomever God is)!

 

[dahermit]

Re: Not current

Says who? You?

Don't make me laugh.

No, not me. It was so reported on the Nova Series, "The Elegant Universe", where they discussed Einstein's theory of gravity, quantum mechanics, and string theory.

With your usual rudeness you must be trying to provoke a flame war.

You will have to excuse numinus folks, he has a social maladjustment that manifests itself in a desperate need to be viewed as an intellectual (the sharpest tack in the box syndrome). You will observe that he frequently will insult posters by suffixing his statements with: "Duh."

 

[Here We Go]

Of course gravity exists. If it weren't for "gravity" the plastic surgeons would go bankrupt.

 

[Chip]

Yes, I believe in gravity, and more so now in my middle-age than when I was younger, as I can attest that gravity's strength increases in direct proportion to my decay.

Perhaps the new European supercollider or laser interferometer labs will soon confirm the existence of the graviton, a theoretical elementary particle sensibly hypothesized as the mediator of gravity based on the quantum theory confirmation that the other three forces are indeed mediated similarly by actually detected quantum particles (electromagnetism via photons, the strong nuclear force via gluons, and the weak nuclear force by W and Z bosons).

Detection of gravitons has heretofore remained elusive, as not only is the graviton theorized to be massless (arising from gravity's unlimited range), but there is an extremely low cross section (likelihood of interaction between particles) for the interaction of gravitons with matter.

The quantum microcosmos is absolutely fascinating.

 

[numinus]

Yes, I believe in gravity, and more so now in my middle-age than when I was younger, as I can attest that gravity's strength increases in direct proportion to my decay.

Perhaps the new European supercollider or laser interferometer labs will soon confirm the existence of the graviton, a theoretical elementary particle sensibly hypothesized as the mediator of gravity based on the quantum theory confirmation that the other three forces are indeed mediated similarly by actually detected quantum particles (electromagnetism via photons, the strong nuclear force via gluons, and the weak nuclear force by W and Z bosons).

Detection of gravitons has heretofore remained elusive, as not only is the graviton theorized to be massless (arising from gravity's unlimited range), but there is an extremely low cross section (likelihood of interaction between particles) for the interaction of gravitons with matter.

The quantum microcosmos is absolutely fascinating.

Einstein already demonstrated that gravity is merely the geometry or curvature of spacetime, or that spacetime is, itself, an effect of gravity.

The problem with elementary particles of gravity, or gravitons is that it must travel at a finite speed, like photons of light. We know that gravity acts instantaneously, that is, at infinite speed.

That is what prompted the question of the thread-starter, I think.

 

[Hobo1]

Einstein already demonstrated that gravity is merely the geometry or curvature of spacetime, or that spacetime is, itself, an effect of gravity.

The problem with elementary particles of gravity, or gravitons is that it must travel at a finite speed, like photons of light. We know that gravity acts instantaneously, that is, at infinite speed.

That is what prompted the question of the thread-starter, I think.

Unless something has been discovered recently, there is no reason to assume gravity travels at "infinite speed", nor is their a reason why it must. If gravity is caused by some yet undiscovered particle or quantum of energy, such as the photon, then one could possibly argue it obeys the sames laws as light and travels at a finite speed.

In fact, the fairly recent discovery that the universe is expanding at an ever accelerating rate defies all scientific logic about gravity. So we may discover that gravity has different rules at a micro level (say, at the level of our galaxy) than it does on a macro level (ie, the universe). This would be a logical presumption if gravity proves to be similar to other sub-atomic particles.

As far as the question "do you believe in gravity", it can be answered the same way Descartes answered the question about whether man exists, "I think, therefore I am." Only in this case "I feel gravity, therefore it exists."

 

[Dawkinsrocks]

Numinuis frequently gets all pseudo-scientific and usually trips himself up.

I believe in gravity because the theory makes perfect sense, every relevant observation I have made supports the theory and neither I nor anyone I have heard of has witnessed a counter-example.

Now, let's just compare/contrast that with the theory of god.

The theory makes no sense, I have never made an observation that supports the theory and I have seen plenty of counter examples.

I think that gravity just wins by a whisker.

A whisker of infinte length and thickness.

 

[numinus]

Unless something has been discovered recently, there is no reason to assume gravity travels at "infinite speed", nor is their a reason why it must. If gravity is caused by some yet undiscovered particle or quantum of energy, such as the photon, then one could possibly argue it obeys the sames laws as light and travels at a finite speed.

http://en.wikipedia.org/wiki/Speed_of_gravity

Isaac Newton's formulation of a gravitational force law requires that each particle respond instantaneously to every other massive particle irrespective of the distance between them. In modern terms, Newtonian gravitation is described by the Poisson equation, according to which, when the mass distribution of a system changes, its gravitational field instantaneously adjusts. Therefore the theory requires the speed of gravity to be infinite.

Without going into a debate on whether there is such a thing as a finite 'speed of gravity', a question the answers for which leave more room for speculation than fact, -- is that enough proof that the true nature of gravity isn't fully known yet at this point in time?

Do not worry yourself too much, though. I hold your highschool physics teacher wholly responsible for the above slip.

In fact, the fairly recent discovery that the universe is expanding at an ever accelerating rate defies all scientific logic about gravity.

Ah, at least someone seems to grasp what I've been saying all along. Yes, the universe couldn't be expanding if gravity is the only tendency governing physical cosmology. We would have experienced the big crunch ages ago, certainly well before the estimated age of 13 billion years. Therefore, it is only logical to postulate something that counter-acts gravity, which is called lambda.

However, postulating lambda gives rise to more questions than it actually solves. In fact, lambda itself, is an enduring cosmological riddle that has found no acceptable solution to this day.

So we may discover that gravity has different rules at a micro level (say, at the level of our galaxy) than it does on a macro level (ie, the universe). This would be a logical presumption if gravity proves to be similar to other sub-atomic particles.

Hmmm?

Im not even sure what you are trying to say here.

http://physics.wustl.edu/cmw/SpeedofGravity.html

How can we really measure the speed of propagation of gravity?

If we could measure the effects on the Shapiro delay to order (v/c)^2, then we could test the speed of gravity. But these effects would be at the thousandths of a picosecond level, hopelessly small.

The real way to measure the speed of gravity is to detect and study gravitational waves. By comparing the arrival of a gravitational-wave signal with that of an electromagnetic signal from an astrophysical source, one could compare the speed of gravity to that of light to parts in 10^(17).

As far as the question "do you believe in gravity", it can be answered the same way Descartes answered the question about whether man exists, "I think, therefore I am." Only in this case "I feel gravity, therefore it exists."

Of course, if you put it that way, then we all know gravity exists. The difficult part is holding this 'existence' to a standard of scientific scrutiny.

And, as I have previously stated, the thread starter was entirely in the correct rational frame of mind to have asked the question.

 

[numinus]

Numinuis frequently gets all pseudo-scientific and usually trips himself up.

I believe in gravity because the theory makes perfect sense, every relevant observation I have made supports the theory and neither I nor anyone I have heard of has witnessed a counter-example.

Now, let's just compare/contrast that with the theory of god.

The theory makes no sense, I have never made an observation that supports the theory and I have seen plenty of counter examples.

I think that gravity just wins by a whisker.

A whisker of infinte length and thickness.

Now you pretend to debate physics with me????

You were hardly coherent in metaphysics, I am still wondering what exactly you are talking about. Now you ignorantly think you can improve your chances in this one.

 

[Dawkinsrocks]

Is that the best you've got?

Clue: Yes

 

[numinus]

Is that the best you've got?

Clue: Yes

I see you are as pretentious in your ignorance as ever.

So tell me, what theory of gravity do you think 'makes perfect sense', hmmm? And what observations have you personally made that supports this particular theory?

 

[Dawkinsrocks]

When I drop something it falls to the ground.

When I look for examples of a benevolent god I see your posts which display anti-benevolence and zero gravity.

See, 1-0 to gravity.

 

[Segep]

when i drop something it falls to the ground.

When i look for examples of a benevolent god i see your posts which display anti-benevolence and zero gravity.

See, 1-0 to gravity.

goooooooooaaaaaaallllllllll!

 

[numinus]

When I drop something it falls to the ground.

When I look for examples of a benevolent god I see your posts which display anti-benevolence and zero gravity.

See, 1-0 to gravity.

Wow, that's so 1st-grader enlightening.

Care to point out the gravitational theory that stupid observation of yours support?