# How does centripetal acceleration of Mars around the sun compare to the centripetal acceleration of the Earth?

Feb 2, 2016

1 in 21.6. The proportion is ratio of (mass)X(inverse-square of distance from the Sun).

#### Explanation:

Data used are from NASA planetary Fact sheet.

Feb 2, 2016

The centripetal acceleration of Earth, Mars and the other planets are all the same, zero.

#### Explanation:

There is no such thing as centripetal force or acceleration for objects in orbit. Einstein's general theory of relativity states that gravity is not a force but a distortion of spacetime. The Sun's mass distorts the 4 dimensional fabric of space time. All of the planets follow geodesics, which are the spacetime equivalent of straight lines in the spacetime which has been distorted by the Sun.

The concepts of gravitational force and centripetal force come from Newton's theories. Centripetal force only applies to spinning objects such as a weight on the end of a string. Einstein said that gravity and acceleration are indistinguishable to an observer. Nevertheless, gravitational force and centripetal force keeping an object in orbit do not exist.