The Flip Side — Hiding From Aliens

Recently I wrote about how the best place for finding alien life might be an exoplanet’s moon.

But there is a flip side — what if we decide we don’t want alien life to find us?  Contacting us first means they assuredly have the more-advanced technology.  Maybe much more advanced.  Would they be friendly?  And remember what European exploration of the New World meant for the Native Americans.  What exotic diseases or other threats might they bring?  So if we decide to play it safe, is there a way we could hide?

There may be.  Returning to EarthSky News, two astronomers at Columbia University have recently published a paper in  Monthly Notices of the Royal Astronomical Society suggesting we could use lasers to conceal the Earth from searches by extraterrestrial civilizations.

The idea is actually simple in concept.  To find planets outside our Solar System, we use a technique called the “transit method”.  This is basically a high-tech search for a minute dip in starlight when a planet moves directly in front of the star it orbits, thus betraying the planet’s existence.  If this is the method we use, which has been very successful by the way, wouldn’t other civilizations try the same method?  So all we would have to do to hide Earth is to turn on a laser to mask this dip in light when we move in front of our sun.

Of course, in real life it’s a bit more complicated.  We would have to identify a planet as a likely candidate for alien life, then turn on the laser when we were facing that direction.  That’s not as difficult as it seems, because we’ve already identified some planets as good candidates.

I’m sure this is nothing that’s keeping many people up at night right now, but it’s interesting to think about.

To read the complete discussion, please go to

Image via ESO / G. HüdepohlVLT_Laser_Guide_Star-e1459520608401

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