Originally published at: https://boingboing.net/2017/09/29/on-the-astounding-lack-of-extr.html
…
1 Like
I work on radio telescopes as an electrical engineer in the astronomy department in Tucson, so I spend some of my spare time thinking about this question. It is not at all surprising to me that we haven’t made contact with any other civilizations on other planets orbiting other stars.
The congratulatory photos of distant planets that are posted in the hallway on the fifth floor, home of the LBT (Large Binocular Telescope) offices, show a planet as being a dozen pixels. That’s not a lot of resolution to make out the effect of civilization on a planet.
I build spectrometers to detect radio signals from molecules in far away places. Another branch of radio astronomy called SETI tries to detect patterns of signals. This is dependent on those other civilizations transmitting signals that are detectable over rather great distances. The field got its start when large TV transmitters were beaming programs into space with very simple modulation.
Nowadays, a mere fifty years later, we have optimized the digital data transmission of moving images so that it takes rather sophisticated equipment to decode the video signal. Also, we tend to use cell phones for entertainment these days, rather than over-the-air broadcast. This method of broadcasting doesn’t beam signals into space, as the antennas are pointed down at the ground.
So yeah, detecting distant civilizations my their electromagnetic transmissions is not likely to happen. And don’t get me started on interstellar travel.
18 Likes
could you transcribe your podcast? Too serial. I can’t skip through the bits I know already without risking skipping the bits I don’t.
Is it just me who prefers things in writing?
14 Likes
Not listened to the podcast yet but how early could intelligent life have first evolved in the universe?
Really? How does that work? Or are you talking stellar spectroscopy?
I prefer things in writing too. I can read very very fast–listening, on the other hand, is TL;DL.
3 Likes
Obligatory:
14 Likes
The interstellar medium, or dust, contains molecules that can be detected at millimeter wavelengths, ~100 GigaHertz. The most common is CO, carbon monoxide at 115 GHz and multiples thereof. There have been over a hundred different molecules detected. The Doppler shift due to motion can be measured easily using a spectrometer (it causes the spectral line to be spread out in frequency), so the local motion of the stuff being viewed can be inferred. The spectrometer works on the radio signal after it’s down-converted to a reasonable frequency range (4-8 GHz), using a tuned heterodyne mixer that’s cooled to 4 Kelvin. Lots of voodoo electronics.
The astronomers know a lot more about this than I do; I just make the machines that produce the data that they use to work out the chemistry and physics of what’s out there.
The telescopes I work on are shown here. http://aro.as.arizona.edu/
They’re big - the one on Kitt Peak is 40 feet in diameter.
5 Likes
Add to that that much of our signaling is now also encrypted at some level and more is being encrypted as we move forward. While some portion of these broadcasts are still made up of artificial patterns in the message framing the fact that more and more of it looks like random noise to an observer might make it hard to identify as coming form an intelligent origin.
1 Like
"They’re bringing drugs. They’re bringing crime. They’re rapists. And some, I assume, are good people.”
___________(attribution unnecessary)
2 Likes
Every star within 60 or so light years of us has received our radio and television signals. That is likely why we cannot find them, they are hiding. After all if you were ET and you saw My Favorite Martian and Lost in Space, wouldn’t you do everything you could to stay clear of the insane people here?
2 Likes
Can’t say that I’ve ever tried to discern a TV signal from the noise that would be encountered after the signal traveled 60 light years. Doesn’t seem too easy, even if you did know which 10-square-arcsecond patch of sky to look in, and what the RF center frequency and video frame rate were.
4 Likes
Oh, go on. Here, I’ll try: time dilation means that it’s possible in principle to travel arbitrarily far distances in a human lifetime (from the perspective of those on board). Ergo, it’s just an engineering problem.
2 Likes
Here’s an interesting idea: ancient people had the very same problem. Why do we have only 300 years of history? The solution was the Flood Myth.
2 Likes
I have really lost patience with the Fermi Paradox lately. It’s only a paradox for people with no real understanding of evolution.
Evolution isn’t teleological, it’s random. This time, here, two legged apes with opposable thumbs evolved sapience. Some other time or place, maybe whales evolved sapience, or elephants. There’s no guarantee that sapience is going to come with a package of manipulatory organs suited to knapping flint, building fire, forging metal, and so on through the technological chain up to building radio telescopes and sending out space ships.
Consider our closest relatives, chimps and gorillas. In response to habitat destruction, gorillas have become more rare - despite being only 1% different from us genetically, they don’t seem able to adapt to new environments. Chimps have managed to diversify from forest dwelling to scrub and savanna dwelling now that humans have come along and chopped down most of their forests. But they never spread out to cover the entire world the way we did. We’re a lot more like rhesus macaques, eager to spread throughout the world and able to put down roots wherever we find ourselves. There’s no guarantee that a sapient ET species is going to be as aggressive at expanding its range as we are, as interested in exploring and colonizing as we are. If they turn out to be homebodies like gorillas or chimps, then they’re probably never going to make spaceships.
Consider sapient pandas or sapient koalas: restricted to a single food source, how easy would it be for a plant disease or an ice age to wreak havoc on their food supply and wipe out their civilization.
What I’m trying to get at is that it’s not just sapience, it’s a big package of multiple attributes that humans just happen to have in combination by random chance, including sapience, which have enabled us to build our civilization and have arguments about Fermi’s paradox on the internet. Another planet with multicellular life is not going to necessarily come up with a similar full package by random chance. But you need a compatible package of many attributes beyond sapience to get ET civilizations capable of and interested in broadcasting evidence of their existence that we could detect.
And we haven’t even touched on the likelihood of evolving sapience. Elephants mourn their dead. Humpback whales have incredibly complex songs that we are only now learning how to hear and analyze, and they exhibit altruism, thwarting the preying of their orca relatives against seals and other species. Clearly elephants and whales are among the most intelligent species on the planet. Yet both have been decimated by human predation. They have been unable to act in a coordinated manner in response to our wholesale murder of their kind, either to flee and avoid us or to defend themselves from us.
If sapience is something that just evolves gradually and inevitably over time, then we’d see more evidence here on earth of beings other than us that could organize and coordinate their behaviour in response to threats. Instead, there’s a quantum leap in mentation between other smart creatures and us.
A quantum leap in evolution means an evolutionary bottleneck, a time when the species nearly died out. We made it. All the other hominids that ever evolved did not. Again, evolution is random. It’s also historically determined - you are stuck with all the random decisions of your ancestors back to the beginning, and cannot go backward in time and choose a different set of optimizations. Each species in a bottleneck needs to kludge together what solutions it can, using random chance.
We can’t be sure what the bottleneck was for us, but Terrence Deacon speculates that it had to do with our peculiar way of living. All other monkeys and apes either have polygamous reproductive arrangements and live in tribes… or they have pair bonding reproductive arrangements and live as isolated nuclear families. Each reproductive strategy is better suited to a different way of life and a different set of habitats.
We, and only we among primates, pair bond but also live in tribes. Dixon suggests that evolving a sophisticated symbolic language (ie, sapience) was our evolutionary kludge to enable us to change our social arrangements without changing our reproductive strategy, or vice versa. Basically we learned to talk so we could discuss our relationships.
And that’s not something that’s going to happen over and over again – rewind the tape to however many millions of years ago when our ancestors needed to shift their reproductive and social strategy, and evolving a sophisticated language is only one of millions of possible solutions that might have been.
We know there are millions of habitable planets in the galaxy. How many millions, we need better telescopes to be able to say. Lots of those planets will probably have multicellular life. But there is no guarantee that any of those planets is going to randomly produce beings that can talk and think like we can. And there’s no guarantee that even if they do, those beings will be both equipped and inclined to behave in ways that would enable us to learn of their existence.
6 Likes
You need a variable speed audio player. I often speed up books and podcasts with plodding readers. Blind audio users can listen at absurd speeds. I assume it’s combo of practice and reassigned brain capacity.
Absolutely, just like immortality and sentient AI. Does recognizing that get a us closer?
Odds are we had a hand in their demise. We keep discovering species that were contemporary with Homo Sapiens.
No. I have some friends who started a podcast and I’m having a hell of a time getting myself to listen to even one episode. And they keep making them!
It doesn’t help that I don’t drive as much as I used to, either.
2 Likes
I stand by the belief that it’s really not that astounding. While it’s a fun thought experiment, and the math is fine, there are a couple of fundamental logical flaws with the conclusion that there’s a surprising lack of aliens. Both of them are surprisingly anthropocentric with a bit of hubris.
First is the idea that if we don’t know something to be true, it must be false (it can’t just be unknown). That assumes that we know everything. We don’t even know if we would be able to recognize signs of alien civilizations to be such even if there were a pile of them on our desks right now.
The second is that the idea that we’ve even really been looking for the right things and in the right places (when we don’t know what either of those are) is a big assumption. Mostly we’ve pointed some radio telescopes at a small fraction of the stars out there and listened to a specific frequency for a few minutes to try to detect a pattern like what we think we would send. That’s all under the assumption that any intelligent alien would make a massively-powerful radio transmitter, tune it to just that frequency, and continuously transmit something that we could recognize in our direction. Because that’s what we thought we would do. But why would they? We don’t even do that and it was our idea!
The logic is sort of like: we’re animals and we wear shoes, so if there are kangaroos and they’re real animals, they must wear shoes too. We’ve been looking in our closet for years (because that’s where we keep our shoes, so naturally they’d put their shoes in our closet too) and we haven’t seen any kangaroo-foot-shaped shoes, so therefore kangaroos must not really exist.
6 Likes
