The Tyranny of Extraterrestrial Messaging

Posted by K R on

Some of the basic assumptions we make about extraterrestrial communication can be woefully naïve. Consider the situation in its gory detail. You decide (perhaps as a species, or perhaps as some resource-rich subset) that you want to ping the cosmos to find out if something else is listening, thinking, and as technological as you are. So you fire up your radio transmitter, or your big laser and start shooting off ‘Hello’ messages. If our circumstances represent a useful template it means that the earliest possible response might come within about 8 years (Earth years of course). That's assuming that there is a responder in the nearest exoplanetary system, listening and receiving your first message at the right time, ready to fire back a response right away, willing to fire back a response, and capable of firing back something recognizable as a response. So, you start listening carefully 8 years later. But nothing comes in. So, you keep listening, telling yourself that it may take time for anyone to put a response together. And you keep listening. Meanwhile, you’ve been busy. In the last 8 years you’ve been pinging the next furthest stellar systems. But for these the roundtrip light travel times go up to 10 years, 20 years, 40 years. Within the sphere of space for a 40-year messaging roundtrip are roughly 150 stars. Time goes by, you decide that star #1 was a dud. But you have to wait longer and longer to find out what happens with the next star and the star after that. And if nothing comes in from the earliest possible responders your assessment of the odds of any randomly chosen star yielding a result has to be revised downwards. As it declines, so too does your resolve. If you do stick it out, waiting for 40 years (and possibly more, to allow for an unknown delay period as extraterrestrial species get their act together to respond), but still hear nothing, what do you do next? Your options are to carry on pinging the same stars, or push on to more distant ones, or to stop. It’s certainly true that the farther your reach the more stars you access – as the volume of space grows with distance cubed. But at the point where the experiment’s timeline exceeds any individual’s lifespan, you’re going to need an extraordinary amount of patience and determination.

Read More: Scientific American

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