Radio Inspired Alien Visitation – The Cold Equations

The math behind alien visitors and the transmission of radio waves suggests that by now there is a sphere around Earth of approximately 116 light-years where our transmissions have spread out.  In this sphere any passing alien radio receiver would pick up on the signals from Earth – however corrupted that may be as they spread out, and indicate that something intelligent was out there.  116 light-years would take us out beyond the nearest 3,496 stars and quickly travel out much further each second.  Of course the equation may not be as simple as that.

Radio waves travel at near light speed in a vacuum, of which we generally believe space is.  But for a vacuum, space is full of a number of things that can influence radio communication.  But receipt of a radio signal sent by the Pioneer 10 Space Probe sent by NASA in 1972 suggests that signals can indeed be sent long distances without being influenced or corrupted.  But just how far these signals can travel before they are influenced by other things like starbursts, black holes, and planets which can serve as their own natural radio transmitters or reflectors is still a matter somewhat open for debate.  But just moving with the notion that there is a spreading bubble of information reaching out into space like a beacon, we can start to create a picture.

In 1952 Kenneth Arnold first saw what he described to newspapers as “flying saucers.”  His sighting soon started a cascade of future sightings, and several more witnesses started coming forward describing incredibly fast objects which could travel with immense speed and power.  Let’s take that first sighting in 1952 and then compare it to the first long range intelligent radio signal ever sent out by Marconi in 1895.  The span of time between 1895 and 1952 means the signal would have traveled approximately 57 light-years into space.  Assuming for a moment that these saucers had been summoned by an Earth transmission and matter can’t travel faster than the speed of light, this would mean the signal had been received by a distant star and then a journey had begun some 28.5 years prior at the most.  This certainly would whittle down the number of stars to look for as the origin of alien species.

So how many stars are there in the 28.5 light-years around Earth?  Currently there are 41 stars within the 28.5 light-year ring around Earth.  And if they had set out on their journey just as the transmissions were reaching their star, and set off for Earth at light speed with perfect acceleration the number is narrowed down to around 5.  Of course the science of astronomy is significantly more complex than that, but a general estimate certainly narrows it down from billions to a handful.  Of course there may be more stars obscured one way or another that are even closer, but it’s always interesting to take a look at the cold equations of space and consider just how close we might be to narrowing down where extraterrestrial visitations may have hailed from – and where we may look one day.