Earl's Science Essay:

Alien   How to Talk to Aliens, and Stuff 

The SETI (Search for ExtraTerrestrial Intelligence) project is undertaking the interesting task of monitoring radio waves from space to determine if they could be of intelligent origin.  The hope is that somewhere in our galaxy there is an intelligent race of beings who, like we, have harnessed the power of radio for communications.  They may even be sending radio beacons into the cosmos hoping to make contact with a species like ours - someone with the intelligence, curiosity, and drive to search for such radio signals.

The problem is that if we receive a radio signal from a civilization, say, 30,000 light years away, then the signal we receive will be 30,000 years old by the time we get it.  If we send a reply, then they will have waited 60,000 years to get a reply to the message they sent 30,000 years ago.  In that time, their sun could blow up, they could wipe themselves out in global warfare, or they could simply lose interest and stop listening before they ever receive our reply.

There has to be a better way.

Well, there may be.  A clever physicist by the name of Dr. John Cramer is setting up an experiment to determine whether quantum entanglement will work across gaps in time as well as across gaps in space

But I'm getting ahead of myself.  I should explain a couple of things first.  Quantum entanglement is the phenomenon wherein two particles (usually photons) exhibit the ability to react instantaneously to one-another's change in state, regardless of the distance between them. This means that if one photon is, for example, polarized in a particular direction, its entangled twin instantly and simultaneously becomes similarly polarized, no matter where it is in the Universe.  Nobody can really explain how or why this happens, but most dismiss the notion that the two particles are actually communicating with one another, because communication of any kind has a top speed of the speed of light, which precludes anything happening instantaneously at a distance. It's just one of those things (like many in quantum mechanics) that just "is".

But Dr. Cramer thought, "What if they are communicating? And not just instantaneously across space, but through time as well?"  He considered the possibility that if entangled photons can work their magic even though they are separated in space, then perhaps they can work their magic even though they are similarly separated in time.  He had several detractors at first, because such a thing would appear to violate causality.  But quantum entanglement is already something of a violation of causality since it appears to involve the communication of information faster than the speed of light.  And aren't time and space two sides of the same coin after all?  It makes no sense that quantum entanglement would work across a gap in space, yet it does.  So why shouldn't quantum entanglement work across a gap in time as well? 

There's only one way to find out.  Dr. Cramer has proposed and is setting up (as of the time of this writing) an experiment in which pairs of entangled photons are produced, and one of them is sent through a very, very long fiber optic cable, and then polarized a certain direction (which is manually configurable) once it exits the fiber optic cable.  Its entangled twin, meanwhile, is aimed at a nearby detector which determines that photon's direction of polarization.  The entangled photons are emitted at the same time and take paths of different lengths, so the photon in the fiber optic cable is still in transit when its entangled twin hits the detector.

What Dr, Cramer hopes to see is that the photon taking the short path to the detector will indicate the direction of polarization that has yet to be applied to its twin as it is still traveling down the fiber optic cable.  This phenomenon even has a name: retrocausality.


Earl at EarlsTV period net is where to find me.
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