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  1. Naked Science Forum
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  4. What exactly is gravity
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What exactly is gravity

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Offline pasala (OP)

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Re: What exactly is gravity
« Reply #60 on: 02/10/2019 14:46:44 »
Quote from: Kryptid on 28/09/2019 20:44:14
Quote from: pasala on 28/09/2019 18:38:08
In case if it is a gas giant, it is spread in a wide area and more particles are exposed to energy, resulting in curvature.  Though energy is weak particles gets into its grip.

So what you're saying is that it depends on the density of the planet, is that right?
that itself is the answer
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Offline pasala (OP)

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Re: What exactly is gravity
« Reply #61 on: 02/10/2019 15:35:08 »
Collected from KipThorne’s lecture:
“Generalrelativity is Einstein’s law of gravity, his explanation of that fundamental force which holds us to the surface of the Earth. Gravity, Einstein asserted, is caused by a warping of space and time or, in a language we physicists prefer, by a warping of space time. The Earth’s matter produces the warpage, and that warpage in turn is manifest by gravity’s inward tug, toward the Earth’s center. The inward tug is not the only manifestation of space time warpage; the warpage is much richer than that. As we shall see, it curves space, it slows the flow of time, and it drags space into tornado-like motions—at least that is what Einstein’s general relativity predicts”

It’s a great speech indeed. 

However the basic question of “what exactly is warping” and how it is being done is still a big question. 

Ok suppose that it is Earth’s matter then Moon is also having same matter only.  Why only Earth’s matter is warping and why not Moon. 

In case, let us assume that if cylindrical carnival “that accelerated motion” warps the space time.  Both Earth and Moon are spinning against their axis with almost similar speed.

If matter warps the space time, whatever size it may, it must warp similarly.  Here it is not so correct to go “inverse square law”, which was almost ruled out by Einstein.

Science developed a lot, cylindrical carnival ride or matter are only limited arena, there is every need to expand our thinking to different other options.

Yours
Psreddy
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Offline Kryptid

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Re: What exactly is gravity
« Reply #62 on: 02/10/2019 16:31:01 »
Quote from: pasala on 02/10/2019 14:46:44
that itself is the answer

Then what do you propose is the relationship between density and distance from the Sun? Eris is much further from the Sun than Neptune is (67.74 AU vs. 30.11 AU), yet it has a much higher density (2.52 g/cc vs.1.638 g/cc).

Quote from: pasala on 02/10/2019 15:35:08
Ok suppose that it is Earth’s matter then Moon is also having same matter only.  Why only Earth’s matter is warping and why not Moon. 

The Moon is warping space-time.

Quote from: pasala on 02/10/2019 15:35:08
Both Earth and Moon are spinning against their axis with almost similar speed.

No they aren't. The Earth spins much faster than the Moon does.

Quote from: pasala on 02/10/2019 15:35:08
In case, let us assume that if cylindrical carnival “that accelerated motion” warps the space time.

The spin of an object can warp space-time (this is called frame dragging), but a non-spinning object will warp space-time as well.

Quote from: pasala on 02/10/2019 15:35:08
If matter warps the space time, whatever size it may, it must warp similarly.

What does that mean, exactly?
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Offline pasala (OP)

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Re: What exactly is gravity
« Reply #63 on: 02/10/2019 17:27:17 »
Quote from: Kryptid on 02/10/2019 16:31:01
Quote from: pasala on Today at 14:46:44

    that itself is the answer


Then what do you propose is the relationship between density and distance from the Sun? Eris is much further from the Sun than Neptune is (67.74 AU vs. 30.11 AU), yet it has a much higher density (2.52 g/cc vs.1.638 g/cc).
I thought that you are following me.
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Offline pasala (OP)

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Re: What exactly is gravity
« Reply #64 on: 02/10/2019 17:30:48 »
Quote from: Kryptid on 02/10/2019 16:31:01
    Ok suppose that it is Earth’s matter then Moon is also having same matter only.  Why only Earth’s matter is warping and why not Moon.


The Moon is warping space-time.

Quote from: pasala on Today at 15:35:08

    Both Earth and Moon are spinning against their axis with almost similar speed.


No they aren't. The Earth spins much faster than the Moon does.

Quote from: pasala on Today at 15:35:08

    In case, let us assume that if cylindrical carnival “that accelerated motion” warps the space time.


The spin of an object can warp space-time (this is called frame dragging), but a non-spinning object will warp space-time as well.

Quote from: pasala on Today at 15:35:08

    If matter warps the space time, whatever size it may, it must warp similarly.


What does that mean, exactly?
I had used words probable or almost but not exact
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Offline pasala (OP)

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Re: What exactly is gravity
« Reply #65 on: 12/10/2019 18:03:43 »
Quote from: Kryptid on 02/10/2019 16:31:01
Quote from: pasala on 02/10/2019 15:35:08

    In case, let us assume that if cylindrical carnival “that accelerated motion” warps the space time.


The spin of an object can warp space-time (this is called frame dragging), but a non-spinning object will warp space-time as well.
"In space, it is possible to create "artificial gravity" by spinning your spacecraft or space station. When the station spins, centrifugal force acts to pull the inhabitants to the outside. This process could be used to simulate gravity. It wouldn't be exactly the same, though, because large Coriolis forces would also be present, and things would fall in curves instead of straight lines".

Well, it is surprise, how a space station, by spinning on its axis creates Gravity.

I think for this theory, cylindrical carnival ride example of Einstein is base:
 “To extend this further, let’s imagine a cylindrical carnival ride where you and your fellow passengers are pinned to the outer surface. The cylinder is rotated faster and faster until the acceleration eases and the movement stays constant. But even once the speed is constant, you still feel the accelerated motion—you feel yourself being pinned to the outer edge of the ride. cylindrical ride, that accelerated motion can warp space and time. It is here that Einstein connected the dots to suggest that gravity is the warping of space and time”.

First of all we have to remember that things on Earth are different, there is  strong Gravity. 

When a cylindrical carnival is rotated, the passengers are pinned to the edges.  Here we are forgetting one important point that:

“Gravity is equal to acceleration”.

For the person at the center, there is no acceleration at all.  Whereas the person at the edges travels full circumference.  As the carnival picks up, Gravity weakens.  The person, say ‘X’, is now gravity free.  Now he carries only original Mass weight and due to air and other forces, he will be moved to the edges and warped at the edges. 

The  relevance to the carnival ride example is Earth.  It is true that Earth is spinning against its axis with lot of speed.  So, Einstein might have thought that similarly things at the edges of the carnival are being warped.  But he forgot his own theory that “Gravity is equal to acceleration”.

If this is true:

“In 1632, even before Newton published his now-famous work, Galileo Galilei wrote about the relative motion of objects familiar in his time: ships. If you are in a closed room on a ship sailing at a constant speed and the ride is perfectly smooth, objects behave as they would on land. There’s no physical experiment you could conduct to tell whether you’re moving or stationary (assuming you’re not peeking out of a porthole). This is the core idea behind relativity, and is the same reason why we don’t feel our planet’s movement around the sun, or our solar system’s movement through the galaxy.

Is there any physical experiment you could do within the confines of your spaceship to tell whether you really were accelerating through space (assuming there were no windows to look out from), or if, instead, you were inside a spaceship stationary on the surface of Earth? Einstein said no—just as Galileo imagined the in distinguishability between a person inside a smooth-sailing ship (confined without windows) and a person on land, Einstein realised that the effects of acceleration and gravity were indistinguishable too”.

“This is called the equivalence principle”,

If the spinning alone is responsible for warping than Galileo’s idea must be wrong and if you are in a closed room of a ship, one must be free from Gravity.  But there is Gravity.  The person inside a closed room, if the ride is smooth will not be in a position to distinguish in between in a closed room and on Earth.

Einstein extended this to Spaceship.  If you are in a spaceship and if it is accelerating through space, you will not be in a position distinguish, on Earth to cabin of spaceship.

Basic idea is that, in distinguishability, closed room of a ship, cabin of space ship to Earth.  Things continued to be same. 

What this indistinguishability tells us, Gravity can be packed.  In a closed room of a ship Gravity is packed.  Inside the spaceship also Gravity is packed. 

The difference is that travelling from Gravity to Non-gravity area.  When the spaceship started accelerating through space, inside the spaceship gravity is packed.  When the spaceship reaches, non-gravity area, slowly gravity disappears.

Thing that is present on Earth is not there in space.  Even if you pack it, it is moving out. 

So, warped space time is present on the Earth.

This is of course not created due to spinning of Earth,. It is already created and present in the space surrounding Earth, which can be packed or moved. 

Suppose if it is on Moon, weak gravity and thus your spaceship can only pack weak gravity.

The space station or space craft is already in inertial position.  There is strong curvature against the space station.  But it is not being warped. 

If we rotate the space station or space craft, curvature weakens, mass gains weight.  Since gravity is equal to acceleration.

Yours
Psreddy
« Last Edit: 12/10/2019 18:11:59 by pasala »
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Offline pasala (OP)

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Re: What exactly is gravity
« Reply #66 on: 10/11/2019 18:02:56 »
“This, in a nutshell, then, is the General Theory of Relativity, and its central premise is that the curvature of space-time is directly determined by the distribution of matter and energy contained within it. What complicates things, however, is that the distribution of matter and energy is in turn governed by the curvature of space, leading to a feedback loop and a lot of very complex mathematics. Thus, the presence of mass/energy determines the geometry of space, and the geometry of space determines the motion of mass/energy”.

Well, here I need not reiterate that curvature of space time is directly determined by the distribution of matter and energy.   So, curvature of space time is directly determined by the mass/energy.  Since,  mass is equated with energy, I would like to take energy only.  It is true that there is strong curvature against Earth. 

Naturally, in other words there is strong energy base on this Earth which I termed it as Potential Energy which is aiding curvature of space time.   

Gravitation is not an attractive force between masses, but a pressure force exerted by spacetime on closed volumes that tends to bring them closer to each other.

Well, it is proved that all closed volumes such as elementary particles Proton(s), neutron(s) and electron(s) pushes their surroundings and produces convex curvature of spacetime.  In fact, this curvature once again depends on availability of energy in the space.  In a 2d space time no elementary particle can curve the space time around them.

When a uranium-235 atom absorbs a neutron and fissions into two new atoms, it releases three new neutrons and some binding energy.  All the elementary particles that ever is released due to nuclear fission start curving space time around them.  This is of course an instant process. 

Sun is also producing most of its energy through nuclear fusion only.  Suppose in a particular time, ‘T1’ total energy produced/present in the solar system is ‘X’.  On the very next minute of ‘T1’ energy produced by Sun is just additional only.  It only maintaining existing energy base in the solar system.  Each time no energy base is created.  “Energy is neither created nor destroyed, it only transforms from one form to other”.  This additional energy, pushes existing energy and start moving out.

 Suppose, let us presume that if Sun suddenly stops producing additional energy or disappears, what happens.  Additional energy only creates pressure/force against existing energy and energy is having an important quality of moving from high to low.  When there is no pressure/force light weakens instantly and it never takes 8 minutes.  This is like electricity, whatever the distance may, if we switch off, light goes instantly. 

However energy spread in the solar system never disappears instantly.  Flow of energy from high to low continues and it takes lot of period.  Meanwhile mass continues to curve the space time.  As the additional energy is stopped, flow/movement of energy is stopped and thus rotation and revolution.  Slowly planets gets into inertial position.  In the outer region, energy weakens further and thus curvature and mass gains weight and start moving out. 

There is energy base on this Earth which is aiding curvature.  When an atom is split, elementary particles freed there from, curves space time around them.  As chain reaction continues, more particles and energy is released into space. All the elementary particles curves the space time and thus radiation increases.

Energy produced or released due to nuclear fission on Earth is just additional only.  Similarly as is done in Sun’s atmosphere, this additional energy on Earth due to nuclear fusion, creates pressure on existing  energy.

Yours
Psreddy

« Last Edit: 10/11/2019 18:10:27 by pasala »
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