When you shoot a cheap lazer toy in the air, where does the light go?

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Does the light stop in the middle of the air when it can’t go any further in the air?

In: Physics
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Eventually, yes. Simply put, light collide with particle in the air. Part of that light get redirected, part of it is absorbed. The redirected part goes in all direction, which is why you can see the light in the air. The absorbed part turn into heat.

The denser the environment, the more it collide, the less goes through. The longer the distance, the more it collide, the less goes through. So most of the time, it can go pretty easily all the way to space, as air itself isn’t too difficult to go through. Once it get in space, it sometime find a few particles to bounce off of, but you’re unlikely to see the laser itself, as it doesn’t have anything to bounce of to go back to your eye.

1) Some will be absorbed (turned into heat) by air.

2) Some will be reflected/scattered back to earth and will mostly be absorbed.

3) Some will reach space and keep going. Lasers are not a perfect straight beam, so the light will disperse over a larger area the further it goes. Eventually it might still hit dust/gasses/….