Where Are They? Maybe They’re Here

There are two reasons for yet another SETI post: (1) we like the subject; and (2) it drives the creationists crazy. You know what SETI is. Those initials stand for search for extraterrestrial intelligence.

Our post’s title, as most of you recognize, starts with Enrico Fermi’s question, which is what underlies the Fermi paradox. Briefly stated, Fermi was asking this: If there are other Earth-like planets in the galaxy where life evolved, some of it intelligent, with the time to develop interstellar travel, then why haven’t they been here, and why don’t we see any sign of them?

We just found this at PhysOrg: Self-replicating alien probes could already be here. It says, with a bit of our bold font added for emphasis:

Mathematicians in Scotland calculate that “self-replicating” alien probes could already have explored our solar system and may still be here but undetectable to our current technologies.

Drs Arwen Nicholson and Duncan H. Forgan from the University of Edinburgh had previously calculated that if a Voyager-sized probe passing through the galaxy picked up speed using slingshots around stars it could travel 100 times faster than otherwise.

Rockets built with our current technology travel at only about one-tenth of 1% of the speed of light, so they’re talking about goosing that up to 10% of the speed of light. That’s a useful velocity — it would let us travel to other planets in the solar system in mere days instead of years. But the chaps from Edinburgh have loftier goals in mind. They hypothesized self-replicating probes in their computer models to calculate the timescale for such probes to disperse themselves radially across space.

Their published paper is in the International Journal of Astrobiology, but you can read it online here: Slingshot Dynamics for Self Replicating Probes and the Effect on Exploration Timescales. We’ll ignore the details of their acceleration technique (and self replication technique, and inter-probe communications) and focus on the big picture. PhysOrg continues:

In all the scenarios the scientists looked at, exploration timescales were reduced when the probes were self-replicating, and they concluded that a fleet of self-replicating probes could travel at only 10% of the speed of light and still explore the entire Galaxy in the relatively short time of 10 million years. This is a tiny fraction of the age of the Earth and the scientists say the results reinforce the idea of the “Fermi Paradox.”

We’ve seen that estimate of 10 million years before. It was probably in an old Analog article we read years ago. In our more ambitious projection, which you can see here: What Are We Learning from SETI?, we used a hypothetical speed of one-third the speed of light, and estimated that if stars with habitable worlds are plentiful and not that far from each other, then humans could populate the galaxy in only one million years. But who cares about our projections? Let’s read on about the Edinburgh work:

Dr Forgan said that the fact that we have not detected or seen any evidence of alien probes in the solar system suggests there have been no probe-building civilizations in the Milky Way in the last few million years or that the probes are so hi-tech we are unable to detect them.

Those are two possible reasons. The article ends with one more:

Another possibility is that probes could be programmed to make contact only with civilizations that pass a set measure of intelligence, which could be the ability to detect the probes.

So there you are, dear reader. Now you can let your imagination loose. Where are they?

Copyright © 2013. The Sensuous Curmudgeon. All rights reserved.

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15 responses to “Where Are They? Maybe They’re Here

  1. docbill1351

    Assuming all that could be done at the speeds calculated, the SRP would zip past our sun in a few days and possibly record “planets here” and nothing more. Reducing its momentum quickly enough to either orbit the sun or a particular planet would require an propulsion technology that would obviate the need for all that slingshot stuff. Once you park in orbit how would you get back up to 10% SoL?

    I know, warp drive. Silly me.

    But can you imagine the report? “Yeah, we found a planetary system around SOL-BR-549 and most of the planets were ok except for one that was absolutely covered in gunk. Pretty disgusting if you ask me.”

    Of course, no sentient being would believe they were made of meat!

  2. there could be thousands of alien probes orbiting the sun and not be detectable. not due to some sort of fancy cloaking device but due to the fact that the solar system is a big place. if we didn’t know where to look for voyager we wouldn’t necessarily be able find it. it could passively observe us and only periodically send a laser communication home which we would only detect if we happened to pass through the beam and be looking.

    i’m a skeptic but i don’t think it’s so crazy to consider the possibility. we know a lot as a species but there is a lot we don’t know. sometimes i think we over estimate our capabilities

  3. TJW says: “there could be thousands of alien probes orbiting the sun and not be detectable.”

    For all we know, a probe could be sitting on the Moon, and it’s been watching this world for thousands of years. It could send occasional broadcasts home only when it’s facing away from the Earth. We’d never know it’s there unless we knew what to look for, or blundered into one of its homeward messages while traveling around the far side.

  4. I just love it that we keep thinking of the possibilities,realizing our limitations,while expanding them all the time. My hope is SETI,leads to an interstellar group chat where I can hear YEC’s get Hitchslapped.

  5. SC: For all we know, a probe could be sitting on the Moon, and it’s been watching this world for thousands of years…

    Did anyone else hear the opening bars of Also Sprach Zarathustra when they read this?

    As an avid SF fan, I’m torn: I want there to be other intelligence in our galaxy but if there is, what if they decide Terra has been infected by these loathsome hominids?

  6. On the other hand, the probes could be looking for dangerous species – you know, the kind that build nuclear bombs. They could be exterminators. They might pay no attention to peaceful species, but the violent ones that have the potential to radiate outward from their home planet will need to be neutralized.

    The message home could be a simple one – send the star destroyer.

  7. Ed says: “The message home could be a simple one – send the star destroyer.”

    No way. It could take 100 years for that message to arrive at Probe HQ, and then several hundred years more for their fleet to get here. That’s way too late. Nobody can police the galaxy like that. The probe would have to be able to act autonomously — and if it were watching and programmed to wipe us out if we developed nukes, that would have already happened. If they knew we existed long ago and they were worried about our potential for violence, then they would have destroyed us long ago. It’s too late to stop us now.

  8. Mainstream science scoffs at my findings, persecutes me mercilessly, and denies me tenure at world-class universities, but that won’t stop me from proclaiming The TRVTH!

    The alien probes are indeed already here.

    They’re in our toothbrushes. They are in our iPhones.

    Some older models are masquerading as microwave ovens, but those ones can’t conduct full brain scans.

    You have been warned. Empty your mind before you brush your teeth.

  9. @ Curmudgeon: I attempted to e-mail you full documentary proof of my assertion above, but it bounced. Do you have a super-sensitive barking nut-job filter in place, or something?

  10. Megalonyx asks: “Do you have a super-sensitive barking nut-job filter in place, or something?”

    Yes. It’s called AT&T. They’re all screwed up. I haven’t been getting my SC email lately. Not my fault.

  11. docbill1351

    I had a friend whose opinion was that women were an alien species.

    Now, I’m just going to lay that 10-foot pole down right here and walk away …

  12. Wouldn’t it be something if they abducted all the discoveroids, only to find this out enroute back to their home base! Too late to turn around, so what to do with them is the question as the abductees babble on and on and on about creationism.

  13. Lewis Thomasonn

    They were unlucky and are deep under “Hambones” Creation Museum,therefore it is impossible to detect any intelligent lifeforms.

  14. Garnetstar

    “…probes could be programmed to make contact only with civilizations that pass a set measure of intelligence.”

    Then they certainly won’t be contacting Earth.

  15. i highly recommend the science fiction series ‘Revelation Space’ by Alastair Reynolds. interesting take on the Fermi Paradox.