2
$\begingroup$

This was a random thought I had, and I can't seem to find any answers. I was thinking that if the Earth shrunk that could possibly cause an increase in distance from the sun resulting in earth having less gravitational pull due to the sun having less effect on it?

$\endgroup$
3
  • $\begingroup$ you seem to be confusing mass, weight and density. Also you are not understanding the concept of 'center of mass' and how it is used as a superposition location point for calculations of forces. $\endgroup$
    – BradV
    Jan 23, 2023 at 22:20
  • 1
    $\begingroup$ If all the mass of Earth was magically reduced to the size of a golf ball the location of its center of mass would remain at its absolute center, same as full size Earth (yeah, I know... Earth is not a perfect sphere but close enough for this discussion). So... the Earth to Sun distance would remain unchanged and gravitational force unchanged. $\endgroup$
    – BradV
    Jan 23, 2023 at 22:27
  • $\begingroup$ Your question is a bit confusing. The gravity you experience on Earth is caused by the mass of the Earth, not by the Sun. Also, the radius of the Earth is tiny relative to the distance from the Earth to the Sun. $\endgroup$
    – PM 2Ring
    Jan 23, 2023 at 23:52

1 Answer 1

5
$\begingroup$

No, gravity is special, because it's pull is related to mass, but acceleration for a given force is inversely proportional to mass.

Galileo noticed this: he observed that two masses, one small and one heavier will fall at the same rate, if air resistance is small.

And orbiting is basically like falling around the sun.

Similarly, but on a much grander scale the orbit of a planet depends only on it's motion around the sun and not on the mass of the planet. If the Earth was magically made lighter, without changing its velocity around the sun, it would continue to move in the same way and at the same distance from the sun, just like Galileo's weights fell at the same rate.

$\endgroup$
1
  • $\begingroup$ This was very interesting thank you, I am new to learning about space, so this is all very new to me. $\endgroup$
    – KaydPepto
    Jan 24, 2023 at 16:01

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .