

Physicists and engineers face off over how to make room for more data - dnetesn
http://nautil.us/issue/11/light/lights-camera-acrimony?utm_source=tss&utm_medium=desktop&utm_campaign=linkfrom

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thisjepisje
_Since the beam spreads out as it travels, the hole is magnified to enormous
proportions over long distances._

Why is focusing the beam before sending it not an option?

edit: I'm guessing the beam would cross itself and go outward again, unless
you start with big antennae.

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beloch
All beams diverge[1]. Try shining a laser pointer on something a few dozen
meters away and compare the spot size to what it is when measured a few
centimeters in front of the laser. You may be able to reduce that size a
little by choosing more optimal focusing parameters (i.e. playing with lenses)
at the laser pointer, but you will not be able to prevent the beam from
diverging.

The _only_ way to obtain a beam of EM radiation that does not diverge is to
place the source an infinite distance away from you. That beam will still
diverge at it's source, but by the time it reaches you the portions you are
able to sample will be perfectly parallel to each other.

[1][http://en.wikipedia.org/wiki/Beam_divergence](http://en.wikipedia.org/wiki/Beam_divergence)

