IAU Ad Hoc Committee Publishes Revised Set of Definitions For SETI Terms (arxiv.org)

RockDoctor writes: An ad hoc committee of the International Astronomical Union has been working for 5 months on revisions and clarifications to the definitions of various terms used in technical and popular discussions of SETI -- the Search For Extraterrestrial Intelligence. They've published their draft report.

The terms of reference -- to account for existing popular and technical uses of the terms -- should mean that no major changes in usage occur, but interesting points do emerge from the discussion paper. For example, in discussing the term "extraterrestrial," their proposed definition ("shorthand for life or technology not originating recently on Earth") includes cover for possibilities such as "panspermia" which may be popular in "popular science," but certainly are not popular in the technical discussions. They go on to discuss that "by this definition, life on another planet with a common origin to Earth life but which diverged billions of years ago would be extraterrestrial, but Earth life accidentally brought to Mars on a human-built lander would not." Waiting for the invasion of the pedants, clutching their feet in their hands.

Comments

O-key

[93 Escort Wagon]

”Waiting for the invasion of the pedants, clutching their feet in their hands.”

I suspect they’re all part of the committee already.

Re: O-key

[Anonymous Coward]

True. Shitty smelly parasites hindu-chimps have been invading stupid america for some time now.

Re:O-key

[RockDoctor]

The paper has 6 co-authors. I know many more pedants than that in read life.

Hmmm

[jd]

Unclear definition of recent. Recent as in X years or recent as in common phylum?

I'd prefer ETL (extra-terrestrial life) - which telescopes can now detect - to be defined and then have layers on that for various levels of complexity. Maybe even start with NTL (non-terrestrial life). Granularity allows distinction and analysis.

Re:Hmmm

[110010001000]

I find the term "extra" terrestrial to be offensive. It seems to imply that those that come from outside of Terra are somehow special, or "extra". Anlso, the pejorative ("non") obviously has a similar issue. In order to promote inclusiveness and equality I would suggest the "MTL" (migrant terrestrial life).

Re:Hmmm

[Impy the Impiuos Imp]

And don't say "sperm", it triggers me.

Re: Hmmm

[Anonymous Coward]

Petition to recategorize the AP style guide. That way the Borg won't be "conquering assimilating aliens" but "undocumented cultural sharers".

No lifeform is illegal!

Re:Hmmm

[jd]

You're trying to be funny, but fail miserably. Don't try to riff off issues you don't comprehend by playing to words you don't understand.

Simple Definition

[Roger W Moore]

Life on a planet other than Earth which did not get there as a result of human activity.

Re:Simple Definition

[Black Parrot]

Life on a planet other than Earth which did not get there as a result of human activity.

Good defiinition, but unless you're extraterrestrial I'm pretty sure you didn't type that while clutching your feet in your hands.

Re:Simple Definition

[Anonymous Coward]

The most interesting case of extraterrestrial life is the life proving the event of the second genesis, or independent origin. Panspermia, for example from a meteor impact, should be a second order concern by comparison, although scientifically very interesting one. So maybe this definition of extraterrestrial life encapsulates the scientific interest more than the philosophical one.

Re:Simple Definition

[AJWM]

I like that one, but you could still get some odd edge case where a recent impact splashes life-bearing rocks to the Moon or Mars.

Not that I can think of any big enough to have done that recently. Even the Canyon Diablo (Meteor Crater, Arizona) impact, about 40,000 years ago, probably wasn't big enough.

Re:Simple Definition

[RockDoctor]

Canyon Diablo wasn't large enough to launch anything into an Earth-leaving trajectory, AFAICT. To leave Earth and arrive on Mars requires considerably more energy than just leaving Earth, because you've got to supply the potential energy to climb a hood distance out of the Sun's gravitational well. and the mid-1980s work on planet-crossing ejecta orbits did specifically address the energetics of that.

Re:Simple Definition

[Roger W Moore]

I like that one, but you could still get some odd edge case where a recent impact splashes life-bearing rocks to the Moon or Mars.

Actually, that is what I really did not understand about the lengthy definition. If such an impact happened "recently" then it has almost certainly happened before and probably lots of times. If so then you really have no idea where life originated and so the only definition that makes any sense is based on planet of residency because that's all you can determine.

NERDS!

[Gravis Zero]

in discussing the role of "Han" their proposed definition ("shorthand for a character created by George Lucus") includes cover for having "shot second" which may be popular in "popular science-fiction," but is certainly not popular in technical discussions.

NERDS! ;)

Hmm, is 65 mya "recent"?

[AJWM]

They go on to discuss that "by this definition, life on another planet with a common origin to Earth life but which diverged billions of years ago would be extraterrestrial,

Interesting. My T-Space books and stories (currently the Alpha Centaur trilogy and several others, more to come) posit terraformed planets whose life diverged about 65 million years ago (post Cretaceous). I wonder if under this definition that would be considered extraterrestrial. (I generally don't -- but I haven't gotten to the real extraterrestrials yet.)

Back in the real world, the end-Cretaceous impact could have splashed life-bearing rocks out to a few thousand light-years by now (don't have the reference handy, but someone calculated the odds and they're surprisingly high for some bacterial spores embedded in a few grams of rock to survive the trip -- although pretty low for that rock to land anywhere fertile beyond our solar system).

Re:Hmm, is 65 mya "recent"?

[AJWM]

Argh. Alpha Centauri, not Alpha Centaur. I even previewed. :(

Re:Hmm, is 65 mya "recent"?

[Immerman]

Is there even any particular reason it would need to be fertile? There's an awful lot of chemovore bacteria living deep inside rocks after all, that might not care where the meteor buried itself so long as the ambient temperature was tolerable and the atmosphere non-toxic enough to allow them to migrate to the local rocks. And once you have life of some sort, evolution will bring it to the surface eventually if it's even remotely feasible - there's all that space and energy-gradient available with no competition.

Re:Hmm, is 65 mya "recent"?

[Anonymous Coward]

In this sense, I think fertile is just shorthand for "provides an environment suitable for the organism to grow and reproduce".

Re:Hmm, is 65 mya "recent"?

[RockDoctor]

but someone calculated the odds and they're surprisingly high for some bacterial spores embedded in a few grams of rock to survive the trip -- although pretty low for that rock to land anywhere fertile beyond our solar system).

A bacterial spore splashed out last year or a billion years ago would be pretty unlikely to then independently invent the mechanisms and chemistry of the eukaryotic cell which is used by all multicellular organisms. So, just at the level of biochemistry, long before you get to trying to work out which part of the biochemistry constitutes the genetic system, you'd know whether or not you had something substantially different to terrestrial life.

I don't think that the Working Group as a whole actually think panspermia is of anything other than academic interest. For "Origin Of Life" ("OOL") research, panspermia is about as useful as a spare dick at a lesbian wedding - all it does is move the difficult and fascinating problem (abiogenesis) to a stage whose conditions could be almost anything less energetic than a plasma. The problem is hard enough when there is still room for valid uncertainty if the original process took place in water solution, or ammonia-water-CO2 triple eutectic (and that system has 3 minimum (local) densities compared to water's one).

I for one...

[Anonymous Coward]

...welcome our SETI definition overlords.

Yeah, right

[Anonymous Coward]

SETI should stand for 'Search For Extraterrestrial Idiots'.

Re:Yeah, right

[RockDoctor]

Why search extra-terrestrially, when we have un-tapped reserves here on Earth?

Seti vs crypto mining

[Larry_Dillon]

I wonder what would forward the search for intelligent extraterrestrial life more, using SETI to analyze radio telescope data or using that compute power to mine crypto-currency and giving that money to researchers?

Just tell us when you find it.

[Anonymous Coward]

Until then, shut up and let us solve some real problems down here. In fact, it wouldn't hurt if you could put your fantasizing aside and help out.

Re:Just tell us when you find it.

[RockDoctor]

I've already helped, by having fewer offspring than I have parents. Have you done anything as beneficial to me as that is to your offspring?

Re:fIrS0t Psot

[RockDoctor]

Not by 6 seconds, you little AC.