eli5 : How does the earth not collide with the sun when orbiting
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The movement of objects in space (and in general) are conserved. Basically this means if something is moving in a direction it will continue to do so unless something acts on it to stop it. (See Newton’s Laws of Motion)
An orbiting body such as a planet has a velocity tangent to the surface of the object it is orbiting. To simplify imagine that the sun is at 0X, 0Y on a grid. The Earth is at 0X, 10Y on the grid, but it is moving at a speed along the X axis.
The sun is pulling on the Earth so it will fall towards the sun along the Y axis. But in the time it takes to fall those 10 units Earth will have moved 10 units along the X axis! Now Earth is at 10X, 0Y and the steady pull of gravity has slowed it’s movement along the X axis to zero. But Earth has picked up speed along the Y axis from falling!
Basically you are now right back to where you started; rotate your grid 90 degrees and start again. The result is a continual orbit.
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