Astronomy Without A Telescope – Bringing The Planetology Home

by Steve Nerlich on May 8, 2010

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We keep finding all these exoplanets. Our detection methods still only pick out the bigger ones, but we’re getting better at this all the time. One day in the not-too-distant future it is conceivable that we will find one with a surface gravity in the 1G range – orbiting its star in, what we anthropomorphically call, the Goldilocks zone where water can exist in liquid phase.

So let’s say we find such a planet and then direct all our SETI gear towards it. We start detecting faint morse-code like beeps – inscrutable, but clearly of artificial origin. Knowing us, we’ll send out a probe. Knowing us, there will be a letter campaign demanding that we adhere to the Prime Directive and consequently this deep space probe will include some newly developed cloaking technology, so that it will arrive at the Goldilocks planet invisible and undetectable.

The probe takes quite a while to get there and, in transit, receives indications that the alien civilization is steadily advancing its technology as black and white sitcoms start coming through – and as all that is relayed back to us we are able to begin translating their communications into a range of ‘dialects’.

By the time the probe has arrived and settles into an invisible orbit, it’s apparent a problem is emerging on the planet. Many of its inhabitants have begun expressing concern that their advancing technology is beginning to have planetary effects, with respect to land clearing and atmospheric carbon loading.

From our distant and detached viewpoint we are able to see that anyone on the planet who thinks they live in a stable and unchanging environment just isn’t paying attention. There was a volcano just the other week and their geologists keep finding ancient impact craters which have revised whole ecosystems in their planet’s past.

It becomes apparent that the planet’s inhabitants are too close the issues to be able to make a dispassionate assessment about what’s happening – or what to do about it. They are right that their technological advancement has bumped up the CO2 levels from 280ppm to over 380ppm within only 150 years – and to a level much higher than anything detectable in their ice core data, which goes back half a million years. But that’s about where the definitive data ends.

Credit: Rahstorf. NASA data is from the GISS Surface Temperature Analysis. Hadley Centre data is from the Met Office Hadley Centre, UK.

Advocates for change draw graphs showing temperatures are rising, while conservatives argue this is just cherry-picking data from narrow time periods. After all, a brief rise might be lost in the background noise of a longer monitoring period – and just how reliable is 150 year old data anyway? Other more pragmatic individuals point to the benefits gained from their advanced technology, noting that you have to break a few eggs to make an omelet (or at least the equivalent alien cuisine).

Back on Earth our future selves smile wryly, having seen it all before. As well as interstellar probes and cloaking devices, we have developed a reliable form of Asimovian psychohistory. With this, it’s easy enough to calculate that the statistical probability of a global population adopting a coordinated risk management strategy in the absence of definitive, face-slapping evidence of an approaching calamity is exactly (datum removed to prevent corrupting the timeline).

Lawrence B. Crowell May 11, 2010 at 3:24 PM

I believe it was Albert Einstein who said something life, “Everything has changed except man himself.” That is the main point of “nothing is new under the sun.”

The point of a Bracewell probe is to communicate one way. If a bio-planet is detected around a star a Bracewell probe is set to wait out the long stretches of time until it detects radio transmissions from the bio-planet. This might take tens of millions of years, so this probe requires some design capable to enduring those time frames. That is not an easy job. Spacecraft last at most a few decades. Then once the AI systems on board begin to detect radio transmissions of sufficient sophistication it announces its presence. It then begins to transmit information in some form of universal code, say the quantum error correction code M_{24} or a Goppa code based on elliptic curves or projective/algebraic varieties. The point would then be to communicate our knowledge to whatever ETI there might come into existence around this planet. I estimate there might be several thousand bio-planets in our galaxy, and we could end up detecting half of these. It is highly unlikely any of them has ETI coincident with our being here.

I increasingly suspect that intelligent life that is technologically capable is not very long lasting. Evolution selects for organisms which are optimal energy exploiters, and I suspect that in the case of intelligent life this leads to the sort of eco-spasm morass we see unfolding around us. Of course I can’t know that is a general rule, but there is no evidence for ETI super-technology activity anywhere in the universe, such as Dyson spheres etc, and clearly there has been no major ETI activity on Earth. Yet maybe there is a Bracewell probe sent by some long gone ETI lurking in the solar system, or nearby space, and it might announce its presence in a fashion similar to the lunar scene in “2001 A Space Odyssey.” We would then download its data and compare notes.

LC

Duncan Ivry May 11, 2010 at 4:39 PM

@ Lawrence B. Crowell

I think that intelligent life will be very long lasting, because that’s what “intelligence” is about, especially solving problems and learning from experience. I’m optimistic.

“Evolution selects for organisms which are optimal energy exploiters …”
If you mean biological evolution, then your statement isn’t implied by the usual definition, and, as far as I can see, it’s no observable fact, and above that, it’s not necessary for evolution to work successfully.

A minor point: “Man” *has* changed, e.g. most Europeans have a relatively new gene which enables them to drink cow’s milk, whereas most people from China can’t. Banal but true.

Uncle Fred May 11, 2010 at 5:57 PM

Just a quick factual corection:

“A minor point: “Man” *has* changed, e.g. most Europeans have a relatively new gene which enables them to drink cow’s milk, whereas most people from China can’t. Banal but true.”

This is an old European wives-tale. I lived with a number of Chinese during my University years (both Northern and Southern Han Chinese students) and they all were perfectly capable of drinking milk. Eating dairy products is just not something mainstream in Chinese culture.

Duncan Ivry May 12, 2010 at 3:42 PM

Uncle Fred: “I lived with a number of Chinese during my University years … and they all were perfectly capable of drinking milk.”

How could it be different: somebody knows somebody ;-) Through my work, I also know some Chinese capable of drinking milk. But this is not the point, and a small number of counter examples says nothing against a statement about *most* people.

But if you don’t like my example, there are other genetic differences between certain human groups, and genetic changes which occured in relative recent times, especially with respect to the immune system. What I got from my readings is, that homo sapiens *did* change in rather recent times, that the human immune system did evolve and continues to evolve, and that the human immune system and pathogens coevolve. E.g. some retroviral human pathogens, including HIV, crossed into human population only recently.

There are geographically restricted patterns of selection in humans. Signatures of positive selection were found in population exposed to malaria. Several alleles common in West Africans but rare in other ethnic groups are associated with protection from severe malaria. A certain allele has been selected in Europe. It confers resistance against HIV-1 but was selected not against HIV, which has arisen as a human pathogen only recently, but against some other infections such as bubonic plague or smallpox.

But, as I said, a minor point.

Lawrence B. Crowell May 13, 2010 at 5:39 PM

To be optimistic let me assume we humans manage to get our affairs in order to survive as a technological species for another 1000 years. This will mean that our footprint on the timeline as a technological species is about two millionths of the time complex life has existed here. That is a very small fraction. Now if there are say a few thousand stars in the galaxy we can use that to estimate the probability for the occurrence of an ETI now. As a simple model I will use Poisson statistics which is

P(n;L) = L^ne^{-L}/n!,

for n the number of occurrences of an event, and L the expected occurrence of an event in a given interval. We use n = 1, the known number of outcomes (ourselves). The L is then the above fraction on the timeline L = 2e{-6}. we have

P(1,L) ~ 2e^{-6}, exp(L) ~= 1

For n = 2, assuming there exist another ETIs in our galaxy now gives us

P(1,L) ~ (2e^{-6})^2/2! = 2e^{-12}

And you can continue on with this and find that the probability rapidly falls down. You can play with other timeline “footprints.”

Given that we human beings are on course to drive half the species on this planet into extinction this century, which amounts to a K-T level extinction on its own, suggests that our tenure on this planet may not be that long.

LC

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