Velocity Reviews > Gravity

# Gravity

Plato
Guest
Posts: n/a

 02-16-2008
OK I understand the below....

Gravity is the other common force. Newton was the first person to study
it seriously, and he came up with the law of universal gravitation:

Each particle of matter attracts every other particle with a force which
is directly proportional to the product of their masses and inversely
proportional to the square of the distance between them.

The standard formula for gravity is:

Gravitational force = (G * m1 * m2) / (d2)

where G is the gravitational constant, m1 and m2 are the masses of the
two objects for which you are calculating the force, and d is the
distance between the centers of gravity of the two masses.

.....OK, Einstein was the second brain to study it seriously........

But my question is:

Are both those dudes correct? Or is gravity just "space" pushing us
inwards to fill the hole a hole in space???

Mike Easter
Guest
Posts: n/a

 02-16-2008
Plato wrote:
> OK I understand the below....
>
>
> Gravity is the other common force. Newton was the first person to
> study it seriously, and he came up with the law of universal
> gravitation:

Okay, so we're going to talk about theoretical physics and how the

philosophers centuries before the common era (BC/AD or BCE/CE) and don't
forget about Galileo at Pisa. The scientific revolution arrived with
Newtonian physics and his 'laws' (theory) about gravity...

> Gravitational force = (G * m1 * m2) / (d2)

.... to explain all kinds of things including planetary behaviors, except
that the math just didn't quite work out right. Those silly planets
just weren't quite doing exactly the right thing.

> ....OK, Einstein was the second brain to study it seriously........

Yep, old Alfred got all involved with a much better theory which was
that of general relativity. Objects can accelerate toward each other
based on the curvature of spacetime caused by their matter which created
a set of field equations named for him and some other dudes.

Under the Einsteinian general relativity theory and equations, various
cosmological behaviors including those of the planets are doing what
those theories and equations say they should be doing much better than
'simple' older Newtonian physical equations.

> But my question is:
>
> Are both those dudes correct? Or is gravity just "space" pushing us
> inwards to fill the hole a hole in space???

Einsteinian gravity theories don't like to get into bed with quantum
mechanics. So the gravity related theory/ies continue to evolve into
quantum gravity, string theory, the theory of everything TOE, and
recently all of the brouhaha about the so-called 'An Exceptionally
Simple Theory of Everything'.

--
Mike Easter

Pennywise@DerryMaine.Gov
Guest
Posts: n/a

 02-16-2008
Plato <|@|.|> wrote:

>OK I understand the below....
>
>
>Gravity is the other common force. Newton was the first person to study
>it seriously, and he came up with the law of universal gravitation:
>
>Each particle of matter attracts every other particle with a force which
>is directly proportional to the product of their masses and inversely
>proportional to the square of the distance between them.
>
>The standard formula for gravity is:
>
>Gravitational force = (G * m1 * m2) / (d2)
>
>where G is the gravitational constant, m1 and m2 are the masses of the
>two objects for which you are calculating the force, and d is the
>distance between the centers of gravity of the two masses.
>
>....OK, Einstein was the second brain to study it seriously........
>
>
>But my question is:
>
>Are both those dudes correct? Or is gravity just "space" pushing us
>inwards to fill the hole a hole in space???

Newton and Einstein were correct in their observations, their math
works and everybody happy, specially NASA.

But at the quantum level it's believed that gravitons flow to and from
particles; the more gravitons a particle attracts the more mass it
will have. http://en.wikipedia.org/wiki/Graviton

--

Bette Davis Eyes

Pennywise@DerryMaine.Gov
Guest
Posts: n/a

 02-16-2008
http://www.velocityreviews.com/forums/(E-Mail Removed) wrote:

>But at the quantum level it's believed that gravitons flow to and from
>particles; the more gravitons a particle attracts the more mass it
>will have. http://en.wikipedia.org/wiki/Graviton

Watch The Elegant Universe
http://www.pbs.org/wgbh/nova/elegant/program.html
--

Bette Davis Eyes

Dan Drake
Guest
Posts: n/a

 02-18-2008
On Sat, 16 Feb 2008 07:33:02 UTC, Plato <|@|.|> wrote:

> OK I understand the below....
>
>
> Gravity is the other common force. Newton was the first person to study
> it seriously,

Well, actually, you could say the first was Galileo, who got the right law
for how things fall, after thousands of years of everybody being wrong.
(And before him some clever Medieval guys did things with the mathematics
of changing speeds, but they never really studied gravity.) But that was
just falling bodies here on Earth, and he never made a universal law of
it.

> and he came up with the law of universal gravitation:
>
> Each particle of matter attracts every other particle with a force which
> is directly proportional to the product of their masses and inversely
> proportional to the square of the distance between them.
>
> The standard formula for gravity is:
>
> Gravitational force = (G * m1 * m2) / (d2)
>
> where G is the gravitational constant, m1 and m2 are the masses of the
> two objects for which you are calculating the force, and d is the
> distance between the centers of gravity of the two masses.
>
> ....OK, Einstein was the second brain to study it seriously........
>
>
> But my question is:
>
> Are both those dudes correct? Or is gravity just "space" pushing us
> inwards to fill the hole a hole in space???

On the physical law, Newton was quite correct so long as you didn't have
to deal with very high speeds or very strong fields, which were impossible
to observe in his day. Einstein's version covered a lot wider range of
conditions. Under "normal" conditions, Einstein's version simplifies to be
the same as Newton's. If it hadn't, he'd have dismissed as crank; in fact,
he *would* have been a crank.

But in the way one *talks* about it, which is more or less a matter of
philosophy, the universal attractive force turns out not to work
universally; or you could say it doesn't even make sense universally.
Einstein's bent space-time does work, so far, provided you don't have to
make it work closely with quantum mechanics.

But but, "pushing us inwards" isn't really what it's about. It's about
taking the shortest course in space-time between two points in space-time.
An orbit really *looks* curved when you look at it, not like a shortest
path at all, but that's just because you're looking at it in 3 dimensions
and then looking at your watch, which is not the right way to compute the
path in the 4 dimensions. I hope this is perfectly clear to you, in which
case there will be *one* person to whom it is clear.

--
Dan Drake
(E-Mail Removed)
http://www.dandrake.com/
porlockjr.blogspot.com

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