# Why would Earth move in straight line without sun's gravity?

If there was no Sun then the Earth would move in a straight line with constant velocity. This is because the space has vacuum and there is no friction in space. This is because if you observe on Earth where there is friction we need to apply force against this friction. But in space there is vacuum and no friction.

Am I right?

## Answers and Replies

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If there was no Sun then the Earth would move in a straight line with constant velocity. This is because the space has vacuum and there is no friction in space. This is because if you observe on Earth where there is friction we need to apply force against this friction. But in space there is vacuum and no friction.

Am I right?
The momentum of the Earth would have to be conserved. The Earth's motion still wouldn't be perfectly straight though, as there are still gravitational effects due to the moon, and the other planets. The Earth would also still continue to orbit the galactic centre. 'Linear' would depend on your scale.

Nugatory
Mentor
Am I right?
Pretty much, yes. This is an application of Newton's first law.

Drakkith
Staff Emeritus