THE SOUTHWORTH PLANETARIUM
207-780-4249   www.usm.maine.edu/planet
70 Falmouth Street   Portland, Maine 04103
43.6667° N                   70.2667° W 
Altitude:  10 feet below sea level
Founded January 1970
Julian Date: 245884.16
2019-2020:  XCIX
              "“Genius is an exceedingly common human quality, probably natural to most of us.”
                                       -John Taylor Gatto



THE DAILY ASTRONOMER
Wednesday, February 5, 2020
On the Golden Record


A great friend of mine from the SMA (Southern Maine Astronomers) contacted me the other day in reference to the Voyager's Billion Year Voyaging article.       He wrote the following:

"I was re-reading this article and reminded myself about the travels and the "Info-in-a-bottle".  The directions on the space-ships, V1 and V2, will be of little use to anyone who may chance grabbing it. The Milky Way is rotating and everything in it is rotating.  In 40,000 years, those directions will be useless, for references, (in my opinion...but I could be wrong), and Earth would forever remain "lost".  Just a thought."

Dear Great Friend of Mine from the SMA,


First, let's look at the Golden Record that is current careening through space aboard the Voyager probe:
record-diagram.jpg

Contained therein (or, in this case, thereon) is as much information as they could possibly inscribe on its surface.   The crafters of these messages faced the daunting challenge of trying to communicate information to a race of beings that wouldn't have any knowledge of any of our languages.    (Aliens only speak the Queen's English in Star Trek movies.)     Even to us, these symbols seem quite perplexing.    They offer instructions about how to play the record, a notion that even confounds most millennials, let alone extra terrestrials.   At the lower left corner one will find a pulsar map, the "directions" to finding us.

The theory is that an alien race will capture the probe at some point,  perhaps in tens of thousands, millions or possibly billions of years in the future.     Provided it doesn't crash into anything, the Voyager probe will continue moving inexorably through the galaxy indefinitely.    If they do find it, they could learn of the probe' origin by examining this "map," which indicates the locations of proximate pulars to our solar system.   Pulsars are rapidly spinning neutron stars produced by the supernova explosions of some highly massive stars.     Each pulsar is distinctive by is spin rate: no two pulsars rotate at exactly the same speed.  Therefore, each spin rate serves to identify a particular pulsar.

Think of it this way:    Let's say we wanted to help people find the Southworth Planetarium.   They would need a lot of help.  Portland is so proud of this institution it is buried seven leagues underground.    Instead of using an address, we list our distances from various known points.  10,129.34 miles from the Sydney Opera House;  279.8 miles from the Statue of Liberty; et cetera.   By specifying enough locations, we can truly pinpoint our location.    (We might be well advised to use closer points of interest, however.)     Of course, tectonic shrugs apart, these locations are not moving relative to each other.   The pulsars and our solar system are moving constantly at different speeds.   Consequently, the configuration of pulsars relative to the Sun and Earth will change slowly over time.    

 Another issue is how to communicate the timing.     Not only will other beings not be conversant in English, they'll have no knowledge of seconds, minutes or hours: time units we devised based originally- on Earth's rotation.        It is possible they will know about the transition periods of atoms, particularly that of hydrogen.      Each pulsar's rotation speed is measured in units of 0.7 billionths of  a second, the time period associated with the fundamental transition of the hydrogen atom.   This atom has also been etched on the record to give the aliens who will eventually decipher the symbols a time reference.

So, My Great Friend from the SMA, we have provided a way for other beings to find Earth.   The more time that elapses, the less likely it will be that they'll find us.  The pulsars will move on, their rotation rate will slow down and, if too much time passses, the galactic motions will shift us far away from these pulsars to much the map will be rendered useless.    It was the best of all possible maps to offer to beings who don't know our language or location.     However, Earth will never be lost....not entirely....somebody somewhere at some time will find us.   Whether this discovery will be to our benefit remains to be seen.



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