How Strong the Earth's Gravitational Attraction Really Is?

[Sirjon]

“Gravity is the force of attraction that makes things fall straight down.”

That is how we commonly describe or define gravity. As to the song “ what goes up must come down”, due to gravity.

Then, think about this:

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https://www.washingtonpost.com/outlook/everything-you-thought-you-knew-about-gravity-is-wrong/2019/08/01/627f3696-a723-11e9-a3a6-ab670962db05_story.html

“ So: “Gravity is what makes things fall straight down.”

Well, yes — depending on what we mean by “straight down.” The path seems straight only because you’re standing still relative to the Earth. As Galileo realized, if you drop a rock from the mast of a ship traveling on a river, its trajectory will appear to be an angle to an observer on the shore. Similarly, to someone outside the Earth who is observing a rock falling on our spinning planet, the path would appear to be on an angle. But the Earth is also orbiting the Sun, so that angle would actually be swooping, creating the appearance of a curve. And because the Sun is orbiting the center of the galaxy, that curve would be a very long curve. And the galaxy is moving toward other galaxies, and the universe is expanding, and the expansion is accelerating: How long and curlicued the rock’s trajectory appears depends wholly on where you are in relation to it. “

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Now, think about the forces that summed up to the given statement above:

1. First, the rotation of the Earth from it’s axis. Somehow you might say, it should bend into an angle, the fall of a thing, instead of gravity “makes things fall straight down”. Scientists would say, the Earth is very big that gravity is too strong that the rotation of the earth from it’s axis will have no effect and still, things will fall straight down. Okay, I will agree.

2. Second, we know well, that the Earth is traveling (revolving) around the Sun. So, we should also consider that factor. So the force of the Earth’s gravitational attraction would be greater than what we expected.

3. Third, the sun is also moving, revolving around the center of our galaxy. Add more force to counter that effect to keep things to fall straight down here on Earth (due to gravity). .

4th and so on - Our galaxy is moving toward other galaxies and the Universe is expanding, if it is right, in accelerating speed.

So, adding all those factors, what should really be the counter-force to keep or makes things fall straight down due to Earth’s gravitational attraction?

It would then contradict what scientists belief that gravitation. is about a million billion billion billion times weaker than the weak nuclear force.

Think about it. 

I'm just wondering if there someone could answer my speculation. 

Edited December 17, 2020 by Sirjon

[Eise]

14 minutes ago, Sirjon said:

“ So: “Gravity is what makes things fall straight down.”

That is wrong already. Assuming you mean that 'objects you drop from a tower, without pushing them in any direction', due to the earth's rotation, objects will not fall exactly straight. The top of a (high) tower has a higher speed then the surface of the earth. So an object will follow a curve, closing in to a straight line more and more during its fall.

18 minutes ago, Sirjon said:

Now, think about the forces that summed up to the given statement above:

In your citation there is no mentioning of forces, only of movements. The example I gave above might be measurable, but I think that the rest of the movements does not contribute big enough to the deviation of a straight line to be measured. 

[MigL]

Congratulations !
You have discovered that all motion is relative ( I.e. relativity ) several centuries too late,

In a couple of hundred more years, you might realize that our best theory says gravity isn't really a force, but a geometric distortion of space-time.

[swansont]

1 hour ago, Sirjon said:

It would then contradict what scientists belief that gravitation. is about a million billion billion billion times weaker than the weak nuclear force.

We can measure the strength of these interactions, and people have done so. As Eise points out, you discuss movement, not forces, and nothing about quantifying the strength, which is necessary to answer your question.

[Bufofrog]

1 hour ago, Sirjon said:

First, the rotation of the Earth from it’s axis. Somehow you might say, it should bend into an angle, the fall of a thing, instead of gravity “makes things fall straight down”.

It is only straight down from the earths perspective, from a perspective motionless relative to the earths rotation the thing would curve.  Both perspectives are equally valid.

The same is true for points 2, 3 and 4. 

1 hour ago, Sirjon said:

So, adding all those factors, what should really be the counter-force to keep or makes things fall straight down due to Earth’s gravitational attraction?

No counter force is necessary.  If you are moving in a car at 100 km/hr and toss a ball up and catch it you would say it went straight up and straight down.  Someone on the road side would see the ball go up and down, but would also see the ball went laterally about 25 meters.  The only difference between the 2 observers is that they are in different reference frames.  Each perspective is equally valid.

1 hour ago, Sirjon said:

It would then contradict what scientists belief that gravitation. is about a million billion billion billion times weaker than the weak nuclear force.

Hopefully you see now that this is not the case.

[Janus]

3 hours ago, Sirjon said:

“Gravity is the force of attraction that makes things fall straight down.”

That is how we commonly describe or define gravity. As to the song “ what goes up must come down”, due to gravity.

Then, think about this:

- - - - - - - - - - - - - - - - -

https://www.washingtonpost.com/outlook/everything-you-thought-you-knew-about-gravity-is-wrong/2019/08/01/627f3696-a723-11e9-a3a6-ab670962db05_story.html

 

2. Second, we know well, that the Earth is traveling (revolving) around the Sun. So, we should also consider that factor. So the force of the Earth’s gravitational attraction would be greater than what we expected.

3. Third, the sun is also moving, revolving around the center of our galaxy. Add more force to counter that effect to keep things to fall straight down here on Earth (due to gravity). .

4th and so on - Our galaxy is moving toward other galaxies and the Universe is expanding, if it is right, in accelerating speed.

So, adding all those factors, what should really be the counter-force to keep or makes things fall straight down due to Earth’s gravitational attraction?

It would then contradict what scientists belief that gravitation. is about a million billion billion billion times weaker than the weak nuclear force.

Think about it. 

I'm just wondering if there someone could answer my speculation. 

All three of the motions mentioned here are themselves subject to gravity. The Earth is in orbit around the Sun, the Sun orbits our galaxy,  the galaxies in our local group orbit a common center of gravity, etc.

This means that these motions are also examples of free-fall.  The Earth is in a free-fall trajectory around the Sun due to the Gravitational attraction of the Sun.  It undergoes a centripetal acceleration towards the Sun, which, due to its tangential velocity, has it following an orbital path.  The object you drop is also attracted to the Sun, has the same centripetal acceleration, and same velocity relative to the Sun that the Earth does.  So, since the Sun effects both equally, you only need to consider the force acting between them.*  The Earth's force of attraction doesn't have to be any stronger than it would if the Earth were floating free in space far from any other gravitational source.

Motion, in of itself is of no consequence, as the Earth and object are already sharing the same motion, and it would take a force acting on one and not the other to change this,

The same holds for the Sun orbiting the galaxy, and the galaxies moving due to mutual gravitational attraction.

* the caveat here is that if the Sun isn't on the horizon, the object will be slightly closer or further from the Sun than the center of the Earth is, so it will have a slightly different centripetal acceleration.  However, even if the Sun is directly overhead, your object is only 1/23456 closer to the Sun.  This is pretty insignificant.   This difference results in what is known as a "tidal force", and is how the Sun effects tides on the Earth.  The tidal effects due to the galaxy and other galaxies are magnitudes smaller than this.

[Sirjon]

 

22 hours ago, MigL said:

Congratulations !
You have discovered that all motion is relative ( I.e. relativity ) several centuries too late,

In a couple of hundred more years, you might realize that our best theory says gravity isn't really a force, but a geometric distortion of space-time.

I knew it already. But the thing is, if gravity is not some sort of force, what makes a thing hit hard on the ground when fall from a high place, considering a free fall?

[Halc]

1 hour ago, Sirjon said:

if gravity is not some sort of force, what makes a thing hit hard on the ground when fall from a high place, considering a free fall?

The real force is from the ground abruptly accelerating the object that was up until that point in freefall.

[John Cuthber]

On a good day, "straight down" is the direction in which something in free fall accelerates, but it's seldom the direction in which it moves.

[swansont]

2 hours ago, Sirjon said:

 

I knew it already. But the thing is, if gravity is not some sort of force, what makes a thing hit hard on the ground when fall from a high place, considering a free fall?

In a Newtonian world, it’s a force.

But, as with basically all physics, when you dive deeper you find that the simple models aren’t quite true.

[MigL]

3 hours ago, Sirjon said:

I knew it already. But the thing is, if gravity is not some sort of force, what makes a thing hit hard on the ground when fall from a high place, considering a free fall?

As Swansont already pointed out, That is the incomplete Newtonian model.
In the much more ( but still not fully ) complete GR model, it is the ground hitting you, as you innocently travel along a geodesic ( free fall ).

[Phi for All]

4 hours ago, MigL said:

In the much more ( but still not fully ) complete GR model, it is the ground hitting you, as you innocently travel along a geodesic ( free fall ).

"We're so sorry, Uncle Albert, we're so sorry if we caused you any pain!" --Linda & Paul McCartney

[Sirjon]

I'm back. Sorry for the long silence. I was busy for a while but I dearly appreciate you people, who participated in this discussion.

Please allow me, to how we perceive gravity. First, and obviously the most prominent is the effect of gravity on our 'sense' of feeling. We feel how we're being dragged or pulled down by gravity, so for many, as a practical argument, agreed that gravity is a force. But in General Relativity, it is more like a descriptive visual effect of gravitation on planets and other celestial bodies in outerspace that defined gravity. which also agrees, mathematically and theoretically. 

Now, we know it well , if two equal forces interact on an object on two opposite directions, the net force is zero. That is the  basis at which I am curious about. If the Earth is rotating on its axis, revolving around the sun and other external factors in ouerspace that may, (if somehow, there's something that if it isn't really a kind of force), acting upon us to keep our feet on the ground and stand straight, it isn't correct to speculate that the gravity equal to 9.80665 meter per second per second is only the net 'value' of computaion? If, then we able to gather all information that externally affects gravity on Earth, then isn't possible that there could be a different or higher computation, at all?  

Edited January 9, 2021 by Sirjon
included some more statements.Reconstructed due to some error on the first time I posted this reply

[swansont]

47 minutes ago, Sirjon said:

I'm back. Sorry for the long silence. I was busy for a while but I dearly appreciate you people, who participated in this discussion.

Please allow me, to how we perceive gravity. First, and obviously the most prominent is the effect of gravity on our 'sense' of feeling. We feel how we're being dragged or pulled down by gravity, so for many, as a practical argument, agreed that gravity is a force. But in General Relativity, it is more like a descriptive visual effect of gravitation on planets and other celestial bodies in outerspace that defined gravity. which also agrees, mathematically and theoretically. 

Now, we know it well , if two equal forces interact on an object on two opposite directions, the net force is zero. That is the  basis at which I am curious about. If the Earth is rotating on its axis, revolving around the sun and other external factors in ouerspace that may, (if somehow, there's something that if it isn't really a kind of force), acting upon us to keep our feet on the ground and stand straight, it isn't correct to speculate that the gravity equal to 9.80665 meter per second per second is only the net 'value' of computaion? If, then we able to gather all information that externally affects gravity on Earth, then isn't possible that there could be a different or higher computation, at all?  

You have Newton’s gravitation law. You can calculate the size of these other contributions.

The acceleration from the sun is about 0.006 m/s^2, but we’re in freefall around it, so we wouldn’t feel anything even if it were larger.

The moon has a small effect in changing the net value of g; this was measured back ~1931 by Loomis, comparing pendulum clocks with quartz clocks. Pendulum clocks depend on g, and there was a ~25 hour cycle of variation measured.