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

In summary, without the Sun, the Earth would move in a straight line with constant velocity due to the absence of friction in space. However, other factors such as gravitational effects from the moon and other planets, as well as the Earth's orbit around the galactic center, would still affect its trajectory. The concept of "linear" motion also depends on scale. The existence of friction does not necessarily impact an object's ability to move in a straight line, but it does require a force to be applied to counteract it.
  • #1
avito009
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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?
 
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  • #2
avito009 said:
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.
 
  • #3
avito009 said:
Am I right?

Pretty much, yes. This is an application of Newton's first law.
 
  • #4
The existence of friction makes us have to apply a force just to keep moving. It has nothing to do with moving in a straight line or not. An object will move in a straight line if there is no force pushing/pulling it in another direction. I can slide a box across a flat piece of concrete and the box will move in a straight line after I let go even though it is slowing down because of friction.

Earth moves with a (near) constant velocity in space because there is (almost) no friction. But it certainly doesn't move in a straight line as it orbits the Sun.
 
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  • #5


Yes, you are correct. In the absence of any external forces, an object in motion will continue to move in a straight line with constant velocity according to Newton's first law of motion. Without the gravitational pull of the Sun, there would be no external force acting on the Earth, thus it would continue moving in a straight line. Additionally, as you mentioned, the lack of friction in space would also allow the Earth to move without any resistance or need for applied force.
 

1. Why does Earth move in a straight line without the Sun's gravity?

Earth moves in a straight line because of its inertia, which is its tendency to resist change in its state of motion. In the absence of any external force, an object in motion will continue to move in a straight line at a constant speed.

2. How does the Sun's gravity affect the motion of Earth?

The Sun's gravity affects the motion of Earth by constantly pulling it towards the Sun. This pull is what keeps Earth in its orbit around the Sun, causing it to move in a circular path rather than a straight line.

3. Can Earth move in a straight line without the Sun's gravity?

No, Earth cannot move in a straight line without the Sun's gravity. The Sun's gravity is the dominant force that keeps Earth in its orbit and prevents it from moving in a straight line.

4. What would happen if the Sun's gravity suddenly disappeared?

If the Sun's gravity suddenly disappeared, Earth would no longer be held in its orbit and would continue to move in a straight line at a constant speed. This would result in Earth moving away from the Sun and eventually drifting off into space.

5. Is Earth's orbit a perfect circle due to the Sun's gravity?

No, Earth's orbit is not a perfect circle due to the Sun's gravity. It is actually an elliptical orbit, meaning that Earth's distance from the Sun varies throughout its orbit. This is because the strength of the Sun's gravity decreases as the distance between Earth and the Sun increases.

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