If the sun was stationary, would the planets still orbit it?

Question

The sun is moving at 217 km/s according to Wikipedia. From what I read gravity is caused by movement, and gravity is what keeps us in orbit. So if the sun stopped moving, and it's gravitational force changed, would the planets stay in orbit or would they fling into space?

Answer 1

Gravity is NOT caused by movement. It is purely a function of mass, modified by distance. Think of a weight resting on a suspended rubber sheet. The weight does not have to move to distort the sheet. That's something like the way gravity works.

If the planets were to stop moving relative to the Sun, they would fall into it. If they were to change their orbital speed, their obital distance would change (slower-closer, faster-farther). If they moved fast enough, they would escape entirely. But the gravity field around the Sun would not change. It's a matter of how close a planet is to its star and how fast it's moving.

Answer 2

The short answer is: yes

Planetary orbital behaviour is determined by the movement of the planets within the sun's gravitational field (and also their mass). The sun's gravity is determined by its mass and not (to any great extent by its movement). If the sun stopped moving, it's gravitational force would not change significantly and the planets would still orbit.

If the gravitational force changed somehow (change in the mass of the sun) then this may change the planets orbits.

Answer 3

Gravity is caused by mass, not by movement. By general relativity, mass increases when you approach very high speeds (approaching the speed of light), but movement in the traditional sense is not a preqequisite for mass.

All particles are moving on a sub-nanoscopic level, and that contributes to mass in a way regarding quantuum theory, but the movement of the sun as a collective has nothing to do with that.

Answer 4

This exchange into proved via Newton. Given an merchandise moving with some speed, and a gravitational tension equivalent to F = GMm/r^2, then there are 3 possible curved paths the article could save on with. It relies upon on how briskly the article is moving. a million) An open direction in the form of a hyperbola. It is presented in from infinity and is going lower back to infinity. it somewhat is an merchandise moving above "escape speed". 2) A closed direction in the form of an ellipse. 3) A parabola, if the article is purely on the boundary of power between the closed and open direction. Newton confirmed that if the strain is proportional to a million/r^2 and the direction is closed, that is going to likely be an ellipse. So it fairly is a effect of the reality that gravity is an "inverse sq." tension.

Answer 5

To be even more technical, you could not prove that the sun is not stationary at the moment and that everything else is moving around it.

Movement is always relative.

And just to emphasise, gravity is certainly not caused by movement - i suggest you read better texts.

Answer 6

The other posters are right. BUT... to get really picky, if the sun were to truly stop moving, that means it would no longer orbit the center of the Milky Way galaxy! So it should then fall into the center of the galaxy, becoming part of the black hole that is supposed to be there.

(And even more technical, even our galaxy is moving in relation to other galaxies... so unless you freeze-frame the entire universe, there is no such thing as "stationary")