You are here:

Physics/Gravity from an individual body

Advertisement


Question
Hello,

Is the individual strength of the earth's gravity affected at all by its distance from the sun ?  Like does it increase or decrease according to its proximity to other larger bodies of gravity ?

Answer
Permit me to make something clear RIGHT FROM THE START.
If it doesn't apply to you, all the better.

Over the years, innumerable people have asked questions of me in a completely disingenuous manner -- they pretend to want to know something, when all they just really want is a lead-in to an argument with me. If this is the game you're trying to play, I DON'T WANT TO JOIN. If you plan to reply to my answer with anything along the lines of, "That's not correct" -- in other words, if you already have an opinion on this question and are just searching for my opinion -- my immediate response will be to click on the button stating, "This is one follow-up too many."
I hope this makes myself clear.


The strength of gravity from ONLY one body is not affected by the presence of other bodies. The gravitation pull of ONLY our Earth does not change at either perihelion or aphelion.

The TOTAL gravitational pull from ALL bodies -- including the pull from bodies OTHER than our Earth -- does, of course, depend on the proximity of those other bodies. We see this at the ocean shore twice every day. If our Earth did not have a moon, oceans would remain at pretty much one level all day, all year. But because there IS a pull of gravity from our Moon, the oceans rise and fall relative to the land. These tides also depend on the gravity pull from our Sun.

In the same way, if you measured your weight at noon, with the moon overhead, the pull of these two bodies would cause a slight reducing in the TOTAL pull downwards towards our Earth. Thus, your measured "weight" would be less than if you measured your weight twelve hours later.

Nevertheless, if you calculated the pull of our Sun and our Moon at both times, you'll find that the pull of our Earth has not changed.

Physics

All Answers


Answers by Expert:


Ask Experts

Volunteer


Expert

Expertise

I can help with understanding physics that does not involve eggs. I will NOT help with academic or professional questions, which are NOT limited only to homework. Please do not waste your time by asking a question that comes out of ANY kind of academic, professional, or business matters.

Experience

Have been fascinated by physical laws ever since I learned, at age seven, that magnets work under water. My study continued through college and has not ceased even after I retired.

Education/Credentials
B.A. in Physics (with honors) from University of California at Berkeley.M.A. in Physics (with honors) from University of Texas Austin.

©2016 About.com. All rights reserved.