UPDATE:  SOLVED by El at 12:50 CDT

It’s Saturday already.  Have you ever noticed how some weeks seem to speed by so fast, you’re not sure what happened to the individual days?  People tell me it’s a sign of old age to gripe about how fast the days go by.

The riddle this week will require a touch of imagination from you, but nothing too radical.  Your answer is an iconic SciFi event.  Are you ready?  ONE for the money…
TWO for the show…
THREE to get ready… and
FOUR TO GO!

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While today’s answer is an iconic SciFi event, you are aware of down-to-Earth versions of this event occurring all through history.

Quite simply, this must occur.

Everything follows from this.

Image by Dietrich Bartel, all rights reserved

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When used as a SciFi theme or plot device, this iconic event strikes a deep chord.

Without this event, SciFi as we know it pretty much isn’t happening.

This event has been addressed by mainstream scientists as well as SciFi authors.

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There we are; short ‘n sweet.  I’m thinking you don’t need too many clues for this one, so enjoy.  You know where I’m lurking.