Why do we feel gravitational acceleration from the Earth and not from the Sun?

  • #1
ejacques
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The acceleration near the earth, due to the force of gravity is g. Now every particle when moving in a curve trajectory had a centripetal acceleration towards the center (say the sun) a=(v^2)/R.
If this is true why we measure weight only with the account of g?
I guess when R is big it might be neglected, but still I wonder 🤔
 
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  • #2
You don't "feel" a gravitational force from the Sun because you feel the same acceleration the Earth does, so you accelerate the same as all your local references. So you just go around the Sun without noticing anything.

You do see variation in gravity due to the presence of the moon and sun, though. This is the cause of tides and spring tides. It's just not a very large effect on a human scale, and depends on the gradient of the gravitational field strength, not the strength itself.
 
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  • #3
ejacques said:
If this is true why we measure weight only with the account of g?
With a scale, we don't measure the Earth's gravitational force directly, just the force that opposes it.

But nothing opposes the Sun's gravitational force.
 
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  • #4
The Earth, and everything on it, is in free fall around the Sun as we move in our orbit. But we are not in free fall around the Earth. Hence you feel the Earth's surface pushing back up on you. If you could stand on a solid surface on the Sun you would absolutely 'feel' the Sun's gravity. Or if we built a giant shell around the Sun and could stand on it without moving in an orbit we would also 'feel' the Sun's gravity.
 
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  • #5
ejacques said:
I guess when R is big it might be neglected, but still I wonder 🤔
If you do the maths, then the gravitational acceleration of the Earth from the Sun is very small:
$$g_{s} = \frac{GM_s}{R^2} = 0.006 m/s^2$$And, using ##T = \frac{2\pi R}{v}## for the period of the Earth's circular orbit, we can rewrite the equation for centripetal acceleration:
$$a_c = \frac{4\pi^2 R}{T^2} = 0.006 m/s^2$$
 
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  • #6
PeroK said:
If you do the maths, then the gravitational acceleration of the Earth from the Sun is very small:
And no matter how large it would be, a scale on Earth would only be affected by its gradient, as @Ibix noted.
 
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FAQ: Why do we feel gravitational acceleration from the Earth and not from the Sun?

Why do we feel gravitational acceleration from the Earth and not from the Sun?

We feel gravitational acceleration from the Earth because we are much closer to the Earth than to the Sun. Gravitational force decreases with the square of the distance, so the Earth's gravitational pull is much stronger on us than the Sun's, despite the Sun's much larger mass.

Is the Sun's gravitational pull on us weaker than the Earth's?

In terms of the force we experience directly, yes, the Sun's gravitational pull on an individual person is weaker than the Earth's because we are so much closer to the Earth. However, the Sun's gravitational pull on the Earth as a whole is what keeps our planet in orbit around it.

How does distance affect gravitational acceleration?

Gravitational acceleration is inversely proportional to the square of the distance between two objects. This means that if you double the distance between two objects, the gravitational force between them becomes one-fourth as strong.

Would we feel the Sun's gravity more if we were closer to it?

Yes, if we were significantly closer to the Sun, its gravitational pull would be much stronger. However, at the current distance of about 93 million miles (150 million kilometers), the Earth's gravity is much more noticeable to us.

Does the Sun's gravity affect us at all on Earth?

Yes, the Sun's gravity affects the entire Earth, keeping it in orbit around the Sun. This gravitational pull is crucial for the Earth's orbit and the stability of our solar system, but it does not affect us individually in a noticeable way compared to the Earth's gravity.

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