The high directionality of lasers makes them great for communications- your energy is concentrated in a small spot... but that means no one will see it unless you are intentionally targeting them. The divergence of the laser used to communicate from the moon was roughly 20radian- thats like shooting between New York and San Francisco and hitting an 80meter wide target.
Beams for interstellar distances would likely be far more collimated. If you transmitted a 1550nm laser out a 10meter diameter telescope with diffraction limited divergence that would be ~8nano-rad... That beam transmitted from Proxima Centauri would be 644,000 km wide- just 4.5 times the diameter of Jupiter- not a big target, and you need to hit that target where it will be 4.2 years in the future.
Space » What makes lasers great for communications, makes the lousy as beacons
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Written by Arrell on , and edited 2 times since. Newest first.
What makes lasers great for communications, makes the lousy as beacons
What makes lasers great for communications, makes the lousy as beacons
The high directionality of lasers makes them great for communications- your energy is concentrated in a small spot... but that means no one will see it unless you are intentionally targeting them.
What makes laser great for communications, makes the lousy as beacons
The high directionality of lasers makes them great for communications- your energy is concentrated in a small spot... but that means no one will see it unless you are intentionally targeting them.