Gravity

[ckissick]

Astronauts orbiting earth are weightless because they are in free-fall while orbiting earth. The spaceship is also weightless for the same reason. Earth is orbiting the sun, just as a spaceship orbits earth. Therefore, Earth is weightless. So if you can be at the exact center of Earth's mass, you are weightless. I'm ignoring other gravitational "forces" - gravity is not a force - like the pull between Earth and Moon, and the fact that orbits decay.

Is this correct? I just came up with this theory. But it makes sense to me.

[stevej37]

Originally Posted by Crowbob

Any further questions or observations?

Isn't it kinda hot down there?

[island911]

Originally Posted by Bill Verburg

mass is a property of matter

gravity is a force that interacts w/ mass ..

Gravity is not a force. Gravity is an acceleration that can produce a force. F_g=mg

[island911]

Not this guy's best vid, but, fwiw.

[GH85Carrera]

We understand the gravity from acceleration, but still don't know just how two objects actually apply forces to each other through a vacuum at millions of miles distance. Think of our sun, 92 million miles distance, and it keeps us in orbit. Otherwise we would fly off into space and all die from cold.

https://en.wikipedia.org/wiki/Graviton

Gravitons are one possibility, but we can't yet figure out how. Yet one thing for certain, gravity always works, and it is nice to know that in the morning when you put your foot out of bed it will go down, and not up to the ceiling 100% of the time.

[hcoles]

Many good YouTube videos on this subject. Maybe slightly OT - but gravity travels at the speed of light.

[The Synergizer]

Kola Superdeep Borehole. 7.6 miles deep.
You wouldn't want to fall in.

https://en.wikipedia.org/wiki/Kola_Superdeep_Borehole#:~:text=In%20terms%20of%20 depth%20below,deepest%20artificial%20point%20on%20 Earth.

[GH85Carrera]

Originally Posted by The Synergizer

Kola Superdeep Borehole. 7.6 miles deep.
You wouldn't want to fall in.

https://en.wikipedia.org/wiki/Kola_Superdeep_Borehole#:~:text=In%20terms%20of%20 depth%20below,deepest%20artificial%20point%20on%20 Earth.

And it is just 3,959 on average to the center of the Earth. Just 3,951.4 miles to go!

The the tunnel that goes through the Earth is going to be just under 8,000 miles of tunnels. Not anytime soon.

[island911]

Originally Posted by GH85Carrera

And it is just 3,959 on average to the center of the Earth. Just 3,951.4 miles to go!

The the tunnel that goes through the Earth is going to be just under 8,000 miles of tunnels. Not anytime soon.

IDK, maybe if CA wants a high-speed rail system to that location. (shrug)

oops, sorry for the dig.

[GH85Carrera]

Originally Posted by island911

IDK, maybe if CA wants a high-speed rail system to that location. (shrug)

oops, sorry for the dig.

I think the opposite of Earth from California is the ocean out close to Madagascar. Not a big demand to travel to and from there.

[Bill Verburg]

Originally Posted by island911

Gravity is not a force. Gravity is an acceleration that can produce a force. F_g=mg

you have that backward

the only way to produce an acceleration on a mass is to apply a force

per the current version of the Standard Model
there are only 4 forces all are mediated by their respective Bosons

not counting dark mass and dark energy

there are only 2 broad categories which make up the universe
Fermions which make up all the mass and Bosons which mediate all the forces

mass is a scaler property which arises from the Higgs particle which is a scaler Boson arising from a scaler field permeating the Universe, all other Bosons are gauge Bosons

gravity effective at large distances per the inverse square law, things become muddled at the ultra short distance like inside an atom, a more inclusive model is needed, only an attractive force, mediated by the not yet detected but hypothesized Graviton, strength scale wrt electro-magnetism 10exp-61

electro/magnetic also effective at large distances per the inverse square law, both attractive and repulsive, mediated by the zero mass gauge Boson called a Photon, strength scale 1


weak nuclear only effective at very short ranges, responsible for radioactive decay, mediated by massive gauge Bosons , W+, W- and Z, strength scale 10exp -4

strong nuclear hold atom together, mediated by the Bosons called Gluons, strength scale x60, has asymptotic freedom, ie can never exist outside the nucleus(in the current universe, at one time immediately after the big bang everything was like the nucleus ie a quark-gluon soup)

[island911]

Originally Posted by Bill Verburg

you have that backward

Do I?

Newton was right, Einstein was wrong?

Your explanation of how F_g=mg=ma (g=a) "is backwards" seems a bit non sequitur and does not flip these relationships. Not even in Newtonian physics.

And I'm fairly certain that the Higgs particle got squished down the drain buy Higgins.

So, the unified theory will have to wait.

[KFC911]

Gravity sucks!

Destroyed my dream of dunking a basketball

[Bill Verburg]

Originally Posted by island911

Do I?

Newton was right, Einstein was wrong?

Your explanation of how F_g=mg=ma (g=a) "is backwards" seems a bit non sequitur and does not flip these relationships. Not even in Newtonian physics.

And I'm fairly certain that the Higgs particle got squished down the drain buy Higgins.

So, the unified theory will have to wait.

excuse me,

Perhaps you need to go back to school for a refresher

basic Physics 101 a force is what causes a change in motion(aka acceleration)

both Newton and Einstein are right w/i certain restrictive domains

Newton was right for large objects moving relatively slowly in relatively weak gravitational fields

Einstein merely refined Newton to explain and describe mathematically w/ fewer restrictions

neither was totally right for all possible scenarios

a major failing of Newton was his ability to describe the orbit of mercury accurately enough, mercury is in a gravitational field just strong enough and is moving just fast enough that Newtons math failed, Einstein corrected that to an exquisite degree that has not been seen to err

Einstein's math fails at very small scales, approaching the Plank distance, here Quantum Theory is necessary to describe what is going on, which it also does exquisitely.

The conundrum of modern Physics lies in reconciling Einstein and Quantum Theory

String Theory and Quantum Gravity being the most promising paths

That is totally incidental and not really relevant to basic forces and accelerations in the usual realms of earth, moon planetary or even large scale Galactic motion

[Steve Carlton]

Gravity puts a curve in space, right? Straight as the Crowbob flies, basically.

[3rd_gear_Ted]

@ which point did they park the J Webb Telescope?

[Bill Verburg]

Originally Posted by Steve Carlton

Gravity puts a curve in space, right? Straight as the Crowbob flies, basically.

There are several ways to look at and describe how gravity works and mass causing a geometric deformation of space-time is one of them


similarly there are different ways to look at how photons work
one is to think of them as particles and the other as waves, each is able to describe certain events that the other can't

That is why Quantum Theory is so powerful because it combine wave/particle duality in a way that as perfectly as we can determine describes reality

[911_Dude]

This is all so very interdastink.

[stevej37]

Nobody answered my question in post 22
I'm really wondering because I have to dig a hole this summer.

[Bill Verburg]

Originally Posted by 3rd_gear_Ted

@ which point did they park the J Webb Telescope?

There many different Lagrange points, described by various mass doublets,

For the Earth-Moon system the Webb is parked at L2 beyond the far side of the moon

keep in mind that there are still other perturbations from other bodies, mainly the Sun and Jupiter