No Earth, No Gravity: What Would it Be?

  • Context: Undergrad 
  • Thread starter Thread starter cdux
  • Start date Start date
  • Tags Tags
    Earth
Click For Summary

Discussion Overview

The discussion revolves around the hypothetical scenario of the absence of Earth and its implications for gravitational acceleration from the Sun. Participants explore the calculations involved in determining this acceleration, referencing both theoretical and practical approaches.

Discussion Character

  • Exploratory
  • Technical explanation
  • Homework-related

Main Points Raised

  • One participant questions the acceleration of gravity from the Sun in the absence of Earth.
  • Another participant suggests that the question may be related to a homework assignment, prompting a discussion about finding the mass of the Sun.
  • Participants mention the distance to the Sun and the Earth's orbital speed as factors in calculating gravitational acceleration.
  • There is a reference to using Google calculator for quick calculations involving gravitational constants and the mass of the Sun.
  • One participant calculates the gravitational acceleration to be approximately 0.006 m/s² based on the distance to the Sun.
  • Another participant expresses surprise at the low value of gravitational acceleration compared to that of Earth, noting the rapid decrease of Earth's gravity outside low orbit.
  • A later reply introduces a related question about the gravitational acceleration at the distance of the Moon from Earth.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the implications of the calculations or the significance of the results, and multiple viewpoints regarding the methods and interpretations remain present.

Contextual Notes

Participants rely on various assumptions, such as the distance to the Sun and the nature of gravitational acceleration, which may not be fully defined or agreed upon. The discussion also reflects uncertainty regarding the relevance of the calculations to the original question.

cdux
Messages
187
Reaction score
0
If there was no earth, what would be the acceleration of gravity from here from the Sun?
 
Astronomy news on Phys.org
This is a fairly simple thing to figure out. Is this for a homework assignment?

Get on wikipedia find the the mass of the sun and go from there.
 
It's not but I realize it's easy to find out:D Nevermind.
 
Two easy things to remember: distance to sun ≈ 150 million km
earth orbital speed ≈ 30 km/second.

v2/R
=============

of course our distance to sun changes by a few percent during the year. the Earth orbit is not perfectly circular. so the acceleration due to sun gravity at this distance is going to change a little.

=============

I would bet this is not homework, just someone who is curious.

You could use Google calculator too. It knows "mass of sun" and it knowns "G" the Newton gravitational constant and it knows "AU" the astronomical unit (mean distance to sun).

So probably you could type into google window "G*mass of sun/(AU^2)" and get it.

Yeah, when I do that it says 0.006 m/s^2
=================

But if I didn't have google calculator handy I think I would use "v-squared over R"
I wouldn't go looking up the mass of the sun, and Newton's G constant.
I would just say v = 3 x 104 m/s
so then v2 = 9 x 108 m2/s2

And then I would divide by R = 1.5 x 1011 meters
 
Last edited:
I'm surprised it's so low compared to earth's. Then again, the Earth's diminishes rapidly out of low orbit.
 
Well it's good to be surprised, so that's good. But a propos what you said about Earth gravity, and practice using google calculator

what would be the acceleration to the Earth at the distance the moon is?
 

Similar threads

High School Is the Earth falling into the sun from gravity?
  • · Replies 7 ·
Replies
7
Views
2K
Undergrad How our Moon and Sun may affect Earth's equatorial bulge
  • · Replies 3 ·
Replies
3
Views
1K
High School What Are Quasi-Moons and How Do They Orbit Earth and the Sun?
  • · Replies 0 ·
Replies
0
Views
2K
Undergrad Speed of the umbra during eclipse vs rate of the Earth's rotation
  • · Replies 3 ·
Replies
3
Views
2K
Undergrad The gravitational center of the Earth
  • · Replies 3 ·
Replies
3
Views
2K
High School Does matter accumulate in Earth's gravity well?
  • · Replies 38 ·
2
Replies
38
Views
5K
Undergrad Force of gravity on JWST while orbiting L2
  • · Replies 4 ·
Replies
4
Views
2K
High School Sun-Earth Encounter: Acceleration, Roche Limit, Rotation & More
  • · Replies 15 ·
Replies
15
Views
3K
High School Earth & Moon Gravity Gradient: Investigating Its Impact
  • · Replies 33 ·
2
Replies
33
Views
5K
High School 'A Brief History of Time' question on gravity
  • · Replies 4 ·
Replies
4
Views
2K