One of the great unknowns of SETI is just how much energy an alien civilization would
be willing to devote to a beacon just blasting out radio contact signals in all directions
hoping someone might pick it up.
But before I get to that, I’d like to announce guest number two for the second Episode of
Event Horizon, link to the channel in the description below where you’ll find a new
clip.
It’s fellow sci fi author Andy Weir, author of the Martian and Artemis, where we will
discuss lunar and Martian colonization, the science behind his books, and writing in general.
The second episode comes out September 27.
Back to SETI, a massive galaxy spanning Kardashev type III civilization may be able to devote
a star or two’s worth of energy to contacting other civilizations, but there’s another
problem.
Any such mega-beacon would be intentionally visible, as would the civilization that created
it.
But, so far, we have seen absolutely no evidence of a Kardashev Type III civilization, at least
as he envisioned one, within our galaxy.
Another problem is time.
It’s not just a matter of their being multiple civilizations within a galaxy trying to find
evidence of each other, it’s also a matter of them existing and sending out signals at
roughly the same period of geologic time to line up.
We simply do not know how long our our civilization, or an alien one, can last.
They may last billions of years, and if so could easily colonize an entire galaxy or
more, or they may not last anywhere near that long, whether they destroy themselves or simply
go extinct relatively quickly.
But, as I’ve been touching on the last few months in these videos, there may be a third
option.
Kardashev might have been wrong, and highly advanced alien civilizations may simply not
need to use anywhere near the collective energy of an entire galaxy.
They may have far lower, more pragmatic energy requirements in order to keep themselves going,
but that doesn’t mean that they don’t want to contact others, they would simply
need to be clever about it.
But, again, there’s that time problem.
If you do what we’ve done and sent out a few one-off signals that do not repeat such
as the arecibo message, at best these become someone else’s Wow!
Signal -- which by the way was not due to emissions from a pair of comets.
I get that comment a lot, but the fact is that explanation quickly fell flat and that
wasn’t well-reported in the media.
So Wow!
Is still unexplained.
But an unexplained blip that looked technological in nature but can’t be verified doesn’t
say much.
If it doesn’t repeat, whether it’s us looking at Wow!
Or aliens looking at the Arecibo signal, then it’s just going to be a mystery.
With the arecibo signal, if anyone happens to be looking at exactly the right time, they’ll
see a brief burst of narrowband radio waves and then nothing, much like Wow!.
It gets even worse if civilizations are rare, say an average of one per galaxy.
If a civilization still wanted to contact other civilizations, the better bet might
be to do it intergalactically.
But, given the distances, that’s a very tall order limited only to the closest galaxies.
But the recent observation of gravitational waves coming from the merger of neutron stars
in another galaxy may give alien civilizations a trick that might give them better chances
of saying hello.
With advanced enough astronomy, alien civilizations might be able to predict such nearby mergers
very accurately.
In a paper by Yuki Nishino and Naoki Seto, link below, they detail that, assuming that
anyone with advanced science would be looking for these mergers, as we do, aliens may choose
to piggy back their signal timed with the merger so that not only would other scientists
in the universe see the event, they would also likely notice the signal and voila.
These sorts of events could herald alien transmissions.
This type of thinking can most likely be applied much closer.
Say aliens only send out signals towards planets with weird oxygen levels in their atmospheres
likely to be caused by life, such as earth, only when their own planet transits in front
of its star relative to earth.
Or, there are of course predictable astronomical events within our galaxy where a signal could
be piggybacked on.
Could the reason we do not see evidence of alien civilizations in the universe is that
things are much more pragmatic and small scaled out there than Kardashev envisioned, necessitating
a much more nuanced, clever and lower power method of contacting other civilizations?
We shall see, and again, as far as radio SETI is concerned, the truth is even with huge
contact beacons we’ve barely looked.
And only then at the closest stars.
We have a lot more searching to do.
Thanks for listening!
I am futurist and science fiction author John Michael Godier currently plugging my new show
Event Horizon again, link below, where each week I become a kind of alternate universe
Sam Neill, except I leave my eyes alone and the higher dimension I take everyone to is
interesting and kinda nice and be sure to check out my books at your favorite online
book retailer and subscribe to my channels for regular, in-depth explorations into the
interesting, weird and unknown aspects of this amazing universe in which we live.