I read laser beams get wider, like a few feet wide by the time they hit the moon, Is that a manufacturing limit, or just something about the physics of laser light? Is a perfect laser beam that doesn’t get wider possible?

Question

I read laser beams get wider, like a few feet wide by the time they hit the moon, Is that a manufacturing limit, or just something about the physics of laser light? Is a perfect laser beam that doesn’t get wider possible?

In: 5280

Answer 1

NASA frequently fires a laser at the moon. The Apollo astronauts left a reflector at one of the landing sites, and NASA used it to measure the distance between Earth and the Moon. The laser is 2 kilometers across by the time it hits the moon, and *25 kilometers* wide by the time it gets back.