Sciency Words A to Z: LGM-1

Welcome to a special A to Z Challenge edition of Sciency Words!  Sciency Words is an ongoing series here on Planet Pailly about the definitions and etymologies of science or science-related terms.  In today’s post, L is for:


In the mid-1960’s, Jocelyn Bell (later known as Jocelyn Bell Burnell) was a grad student at Cambridge.  Through Anthony Hewish, her Ph.D. advisor, she became involved with the construction and operation of a brand new radio telescope specially designed to hunt for quasars.  But that telescope ended up finding something more than just quasars.

Bell Burnell recounts the story in this speech, as published by Cosmic Search Magazine.  Part of her job was analyzing data from the telescope, which came in the form of chart paper—literally miles worth of paper—produced by a set of “3-track pen recorders.”  And on those chart papers, Bell saw some odd markings, which she described as bits of “scruff.”

Naturally, that scruff required further investigation. Faster, more accurate recordings were made, and the scruff resolved itself into a series of regular radio pulses.  These pulses were so consistent, so evenly spaced, that you’d think they must be artificial. It was almost like someone out there in space was trying to get our attention!

Bell named the source of those radio pulses LGM-1, which stood for little green men #1.  But as I said in a previous post, when it comes to discovering alien life, scientists must hold themselves to the same standard as a court of law: proof beyond a reasonable doubt.  While Bell may have been happy to joke about little green men, she did not actually believe that’s what she’d discovered.  As she explained in her speech:

Just before Christmas I went to see Tony Hewish about something and walked into a high-level conference about how to present these results.  We did not really believe that we had picked up signals from another civilization, but obviously the idea had crossed our minds and we had no proof that it was an entirely natural radio emission. It is an interesting problem—if one thinks one may have detected life elsewhere in the universe how does one announce the results responsibly?  Who does one tell first?

After her Chistmas break, Bell returned to work and found a big pile of fresh data to analyze, and there was more “scruff.” In total, Bell found four distinct radio sources, located in completely different parts of the sky.

And that finally put the “little green men” hypothesis to rest.  It seemed highly unlikely that four different alien civilizations, located in completely different regions of space, would all try to get our attention at the exact same time, in the exact same way, using the exact same radio frequencies.

LGM-1 is now believed to be a neutron star, spinning rapidly, projecting twin beams of radio waves out into space like some sort of cosmic lighthouse.  It’s an entirely natural phenomenon, the result of a supernova explosion.  Today, we call this sort of object a pulsar.

Next time on Sciency Words A to Z, maybe it’s time to stop waiting for aliens to contact us.  Maybe it’s time we tried to contact them.

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