SETI is a tricky business.
When the idea came up decades ago to turn a radio telescope to the heavens to listen
for signals of alien technological origin, no one quite knew what to expect.
It might have been that the galaxy was lit up with alien signals coming from all directions.
Or intentionally in our direction, as Carl Sagan mused about in his book Contact, and
the subsequent movie.
All of these ideas involved powerful radio beacons, perhaps making themselves known by
using the language of mathematics and science.
But, this did not pan out.
We do not see obvious signs of advanced alien civilizations ruling the milky way.
In fact, so far, we’ve seen nothing unambiguous at all.
And that’s a problem.
With radio astronomy, unambiguous is an important term.
If you turn a radio telescope towards the stars, you will get weird signals, some of
which may have no ready explanation.
But what you can’t do is immediately suspect they are alien, all you can say is we don’t
know what that is, at least until someone thinks of a natural explanation later.
This does not of course rule out the possibility that we will detect an alien signal some day,
unambiguous signals are no problem to create, we do that all the time ourselves.
If someone were to pass within a few light years of earth and they had sensitive enough
equipment, they’d see us and they’d know that our plethora of narrowband signals we’re
producing are technological in nature, there would be no other explanation.
Go a bit further out though, such as the nearest star to us proxima centauri, and we would
actually be pretty difficult to detect without some seriously sized equipment.
But that’s radio SETI as was envisioned decades ago.
And while radio SETI is well worth the effort, even if there aren’t contact beacons blasting
out signals, there could be anything from interceptable internal communications, feeds
from probes, and even leakage from alien propulsion systems, a subject I broached recently with
guest #3 for my new show, Event Horizon, link below for a clip.
The guest was probably easily guessable given the plug I recently put on here for the Mars
Society Convention but it’s Robert Zubrin.
A lot of people watching this channel will know Dr. Zubrin from his Mars exploration
advocacy, but he also wrote a paper back in the 90’s that detailed several types of
detectable alien propulsion systems, such as laser driven light sails, link to the paper
below.
We discussed that, and of course Mars, but other topics that he’s wrote about over
the years that most interviewers don’t get into with him.
The full episode comes out October 4.
The point is, we may be more likely to accidentally detect aliens just by seeing the normal emissions
of their civilization rather than see an intentional contact beacon.
But, there could also be a far more efficient way to make contact.
I’ve covered one variant of this on this channel, the idea that sleeping von Neumann
self-replicating probes could be present in the solar system waiting for the right time
to start transmitting to us.
This seemingly makes sense, it takes a lot less time and energy to talk to a local beacon
than one that’s far away.
But there are also issues with von Neumann probes, such as if they were to lose control
of their own reproduction and literally turn the entire galaxy into von Neumann probes.
So there may be an alternative.
Nodes.
In a paper by John Gertz, link below, he details that aliens might rather position communications
nodes, a network, at intervals within the galaxy that can search for and identify nearby
exoplanets that may harbor civilizations.
These would then simply wait until they detected radio emissions that unambiguously indicated
the presence of a civilization.
They could monitor multiple star systems at once, and relay their communications rather
than use huge amounts of energy to beam directly to home.
Such a network would still operate at near the speed of light when communicating back
to the alien’s home world, which limits communications, this is a relativistic universe,
but it would also locate information about them very close to us, allowing it to transmit
a virtual encylopedia’s worth of information about the alien civilization to us as soon
as the node was ready to communicate.
This would also be a solution to the Fermi Paradox.
If such nodes exist, and they direct their transmissions towards other nodes very narrowly,
we would not see them unless we were in the path of those communications.
If we were not then we’d never know, at least until a node contacted us, that an extensive
galactic network of communications nodes exists.
Maybe it does.
Thanks for listening!
I am futurist and science fiction author John Michael Godier currently worried about aliens
interpreting earth.
What if the first communication we receive from an alien node is an Amazon order for
lithium grease because it ran out, or how about “We eat science fiction authors”
in a comments section on youtube -- this has happened -- or a demand by the avians of Slandthor
5 to hand over the Colonel immediately or else.
So very worrying, and for more such worrying material be sure to check out my books at
your favorite online book retailer and subscribe to my channel for regular, in-depth explorations
into the interesting, weird and unknown aspects of this amazing universe in which we live.