Gravity vs Mass

[Thief]

The moon falls in a stable orbit around the Earth

I hear that.... a lot

I never bought into it

the moon is not...... 'falling'....anywhere

it's trying to get away

and gravity is a chain that binds it

 

[Thief]

If Matter did not exist what would be the relevance of gravity?

and THAT leads us to the big bang

gravity made it happen?

or was that just the will of God?

 

[Thief]

Gravity is a function of time.

time does not exist
it is only a cognitive device.....measurement

divisions of length.....
divided by divisions of movement
both measures created by Man to serve Man

Time is not a force or a substance
it's an illusion

and Albert E. has been credited for having said so

I suspect he realized his 'greatest blunder'
and then said so

He used an illusion in his equation to describe reality

ooooops

 

[Valjean]

I hear that.... a lot

I never bought into it

the moon is not...... 'falling'....anywhere

it's trying to get away

and gravity is a chain that binds it

No, it's in orbit. An orbit is a circular free-fall around a mass' gravity well. It's continuously falling, but its forward momentum is enough to make it continually miss the mass it's falling toward.

So the moon can be said to be falling.

 

[halbhh]

I hear that.... a lot

I never bought into it

the moon is not...... 'falling'....anywhere

it's trying to get away

and gravity is a chain that binds it

You're right, in that you've said the same thing in different framing. I have no objection to that classic old framing. It's less full, but perfectly adequate as a starting point.

 

[Heyo]

For example, a gravitational wave varies in time.

It has been said that mass bends spacetime in the direction of time. Time flows slower in the presence of mass (and there is a formula for that, q.v. time dilation). But time doesn't appear in the general explanation of gravity.
It should be possible to reformulate the formulas so that gravity literally becomes a function of time.
The questions are: Can that be done so that it corresponds to reality? and Would that model help us to gain new insights?

 

[Terrywoodenpic]

It has been said that mass bends spacetime in the direction of time. Time flows slower in the presence of mass (and there is a formula for that, q.v. time dilation). But time doesn't appear in the general explanation of gravity.
It should be possible to reformulate the formulas so that gravity literally becomes a function of time.
The questions are: Can that be done so that it corresponds to reality? and Would that model help us to gain new insights?

There was a very recent BBC (last two weeks) program on the subject of gravity. And they concluded with the statement on the latest thinking that gravity was a funtion of time.

 

[Native]

Like photons? Yes. We know light comes in particles (and waves) and that those particles move at the speed of light, which forces them to be massless.

This is a contradictory statement. What then if a "photon particle" slows down beyond the speed of light, do it then get mass? This is nonsense.

Nope. Light comes only in EM waves but it affects particles and there is no such thing as a "photon particle" at all.

 

[Native]

No, it's in orbit. An orbit is a circular free-fall around a mass' gravity well. It's continuously falling, but its forward momentum is enough to make it continually miss the mass it's falling toward.

So the moon can be said to be falling.

Of course the canon ball "falls" to the Earth as it travels through the atmosphere. This motion is similar to a space probe entering the Earth atmosphere where it is slowing down because of the atmosphere itself.

 

[Darkforbid]

There was a very recent BBC (last two weeks) program on the subject of gravity. And they concluded with the statement on the latest thinking that gravity was a funtion of time.

Can you find a link for that or just post the name of the show

 

[Polymath257]

This is a contradictory statement. What then if a "photon particle" slows down beyond the speed of light, do it then get mass? This is nonsense.

Photons move at the speed the speed of light. When they go through matter, their progress is slowed by interaction with matter (they are scattered), so the effect is a slowing of light. Photons are still massless.

Nope. Light comes only in EM waves but it affects particles and there is no such thing as a "photon particle" at all.

Directly contradicted by observation. We have detected single photons.

We have also detected the wave properties of electrons, neutrons, and some atoms.

 

[Polymath257]

It has been said that mass bends spacetime in the direction of time. Time flows slower in the presence of mass (and there is a formula for that, q.v. time dilation). But time doesn't appear in the general explanation of gravity.
It should be possible to reformulate the formulas so that gravity literally becomes a function of time.
The questions are: Can that be done so that it corresponds to reality? and Would that model help us to gain new insights?

Gravity curves spacetime: both space and time are affected. The degree of curvature is a function of all three coordinates of space and the time coordinate.

General relativity assumes a 'metric' on spacetime that treats one coordinate differently than the other three: that is then the time coordinate. The coordinate itself can be arbitrarily defined, BUT the 'proper time' along any path in spacetime is the same for all observers.

 

[Polymath257]

I hear that.... a lot

I never bought into it

the moon is not...... 'falling'....anywhere

it's trying to get away

and gravity is a chain that binds it

If, at any point, you draw a stright line in the direction the moon is moving, the actual subsequent movement is closer to the earth than that tangent line. So the moon is accelerating towards the Earth at all points: it is 'falling'.


Think of it like this. Suppose you throw a ball. There is both motion forward and a motion downward. The downward part is said to be the ball falling.

Now, throw the ball faster. it 'falls' at the same rate, but is going faster forward, so it lands farther away.

if you throw that ball fast enough, it 'falls' at the same rate that the curvature of the earth falls. At that point, the ball keeps on falling all the way around the Earth: it is in orbit.

The same is happening with the moon, only farther away. if it were not moving *sideways* from the Earth, it would fall directly to the Earth. But the sideways motion means that, as it falls, it also follows the curvature of its orbit around the Earth.

 

[tas8831]

I have a question of which I will not post
I already know.....no one can answer it

but it does relate to this topic and so.....a redirect and a blindside
right up front

do you THINK you understand gravity?
and WHAT has mass got to do with it?

and if the Creator gets a mention
don't be surprised

I would not at all be

surprised if...

You want to think that a creator has

anything to do with mass or gravity.

That is what those.... unable to grasp

Science do. They tell tall tales.

 

[tas8831]

*sigh*. Yes, that is the equation for a mass that is not moving. The more general equation that even works for massless particles is

E^2 =m^2 c^4 +p^2 c^2

where E is the energy, m is the (rest) mass, and p is the momentum.

So, for photons, m=0, giving E=pc.

For a particle with mass m and velocity v, the momentum is given by

p=(mv)/sqrt(1-(v/c)^2 )

As for 'cosmological explanations' and 'correctness', the correctness is determined via observation. The phrase 'cosmological explanation' is likely to be philosophical rubbish.

I find these videos and articles about 'how everything they taught you was a LIE' (I know the video in question did not, directly, do that, but it is of a similar genre) to be annoying in the least, exasperating at the worst.
Came across one titled something like 'If you believe the moon's gravity affects tides you believe a lie' or some such rot. It was an actual physicist. The gist of his "it's a LIE!" was that gravity does not act on "the oceans", it acts on the water molecules IN the oceans, thus the lie. And he took like 10 minutes to "support" his conclusion.

 

[tas8831]

in eighth grade......sooooooooooo long ago

two classmates were given the assignment.....What if gravity failed
and they assumed all of the large objects....and us.....
would float off into space

at the time I was naïve enough to ask.....
would not the atomic structures fail?
and we simply pop into the nothing from which reality came forth?

kinda dropped a bomb on their science report

but neither did I think I was right
I was just asking

Good thing you didn't think you were right.

Didn't you claim to have won some kind of science award?

 

[Polymath257]

Of course the canon ball "falls" to the Earth as it travels through the atmosphere. This motion is similar to a space probe entering the Earth atmosphere where it is slowing down because of the atmosphere itself.

Are you saying that if there was no atmosphere, the ball would not fall????

Again, we have direct observational evidence contradicting that: both in labs in vacuum containers, and on the moon with a gold ball.

 

[Subduction Zone]

This is a contradictory statement. What then if a "photon particle" slows down beyond the speed of light, do it then get mass? This is nonsense.

Nope. Light comes only in EM waves but it affects particles and there is no such thing as a "photon particle" at all.

Einstein won the Nobel Prize in physics showing that you are wrong:

Photoelectric effect - Wikipedia

 

[Native]

Photons move at the speed the speed of light. When they go through matter, their progress is slowed by interaction with matter (they are scattered), so the effect is a slowing of light. Photons are still massless.

Of course "photons are still massless" as it newer had any mass in the first place, hence it cannot be described as a particle at all.The scattering of EM light waves is a simple diffraction of light waves when it hits particles.

 

[Polymath257]

Of course "photons are still massless" as it newer had any mass in the first place, hence it cannot be described as a particle at all.The scattering of EM light waves is a simple diffraction of light waves when it hits particles.

Yes, you can have a particle without mass. Sorry, but you need to update your conceptual universe.

And no, diffraction is another phenomenon. There are many *different* phenomena associated with the wave properties of light (polarization, for example), but we also can detect individual photons and measure the particle aspects of light as well.