My_House__My_Blue_Planet_Earth

Astronomy Without A Telescope – Bringing The Planetology Home

8 May , 2010 by

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).

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Aqua4U
Member
May 8, 2010 4:50 PM

OF COURSE! Stealth aliens… it all makes sense now… the guy down the street… the mailman… the Comcast guy…my next door neighbor…. the X-37B.

Actually you bring up a good point. Intelligence breeding benevolence is one thing, due caution another.

Le Theatre Du Bruit
Guest
May 9, 2010 2:02 AM

I love this. It spurred my imagination for the day

Lawrence B. Crowell
Member
Lawrence B. Crowell
May 8, 2010 7:24 PM
Instead of Asimov I would consider AC Clarke. Suppose we find by various chemical signatures of some terrestrial planet indicating the presence of life. The so called “red edge” at around 500nm is a good sign for photosynthesis. So there may be life there, but this planet is 400 light years away. It is also radio silent, no signature of some ETI phoning out. So sending a probe is a bit problematic, for it will take over 800 years to get a return — a bit like reading the books of Thomas Aquinas for the first time. So what might we do? We might decide to send a probe anyway, but the purpose might not be to send… Read more »
Uncle Fred
Member
Uncle Fred
May 8, 2010 11:35 PM
As I see it, the scenario as proposed by LC is the more likely one to postulate about. Firstly, we are unlikely to detect any early stage communications as it is my understanding that radio/TV signals degrade into static at around 1-2 light years (please correct me if I am wrong). Secondly, the odds of us making contact with a contemporary civilization within our galaxy is pretty low. Lets assume we are primarily interested in looking for life on worlds that have followed a path of development similar to our own. Despite the seemingly endless quantity of stars in the Milky Way, due to many factors (effects of Jovian brother planets, main-sequence metal rich G-class stars, etc, galactic… Read more »
Spoodle58
Member
May 9, 2010 3:19 AM

@ Steve
And I thought I watched to much Star Trek. smile

Lawrence B. Crowell
Member
Lawrence B. Crowell
May 9, 2010 5:11 AM
@ Uncle Fred: You are right about our radio transmissions falling off into noise. If one considers radio waves as a radially symmetric flow of photons (particles), then the number of photons N, is constant. They are conserved, but the number of them drops off with the radius. An imaginary sphere enclosing the transmitter has an area A = 4pi r^2, for r the radius of this imaginary sphere. The number of photons per unit area on this sphere is then N/A = N/4pi r^2. So the signal drops off as the reciprocal of the radius squared. By extension the electric field line from a charge is also conserved which is why the Coulomb law is a 1/r^2… Read more »
Lawrence B. Crowell
Member
Lawrence B. Crowell
May 9, 2010 5:33 AM

Interesting comparison with STNG – The Inner Light, I had to look this up to remember what this epsiode was. This was one of the better episodes. So thiese involved “Bracewell probes.” According to the Wiki-P entry these are related to von Neumann probes. In some sense they would have to be in order to maintain functionality over very long periods of time.

LC

Torbjorn Larsson OM
Member
Torbjorn Larsson OM
May 9, 2010 5:35 AM
What we will actively do when respectively if we observe biospheres and ETI is an open question, there is no forcing constraints on those possibilities. Likely we will do nothing respectively attempt communication FWIW, which is much cheaper than sending probes. The observation of biospheres is much more exciting in the perspective that it can help answer such things as how life got started. I can’t wait for some statistics on biospheres! … but I have too. Darn. Some reflections on raised proposals: – “cloaking technology”. I got the impression that there is or will be a “no go” prediction, as phase detection will detect any “bending around” of light. Through projection (projecting the background in front) would… Read more »
Torbjorn Larsson OM
Member
Torbjorn Larsson OM
May 9, 2010 6:20 AM

Ops, that is “water ice and clouds shows up IR reflecting”.

While I’m at it and before IVAN3MAN gets wind of this:
“there is no forcing constraints” – there are no forcing constraints
“I got the impression” – I get the impression

“Using the then model” – Using the then models
“Its no skin” – It’s no skin

Aqua4U
Member
May 9, 2010 2:40 PM

Imagine the ET probe’s crew’s astonishment at sensing a similarly cloaked vessel also on orbit. Then quite suddenly, the Probe and crew wink out of existence…

Lawrence B. Crowell
Member
Lawrence B. Crowell
May 9, 2010 11:20 AM
Learning that alien biospheres exist would be a huge scientific coup. Maybe if one is close enough we could send a robotic probe there to get a close up look at this alien biology. There is nothing which forces us to send a Bracewell type of probe to such a solar system which waits out enormous stretches of time to contact possible future ETI. Such a proposal would be expensive and is not the sort of thing tea bagger types are eager to fund. At the end of it all we might wonder if all our observations of the universe, study and theoretical understandings are just howling at the moon. Maybe if we are fortunate enough we might… Read more »
Duncan Ivry
Guest
Duncan Ivry
May 9, 2010 4:33 PM

@ Steve Nerlich

My compliments to you on this article (without any irony or sarcasm on my side). You promote a politico-scientifical agenda disguised as a short story in the literary tradition of projecting our own real or supposed problems onto a society existing far away in space or time. I appreciate this, and it is far better than what somebody tried here on Universe Today some time ago.

Jlazor
Member
Jlazor
May 9, 2010 11:08 PM
I doubt that an alien civilization would face a problem identical to the one we are having. The chemistry of life on other planets is probably so different from ours that their problems will also be different. Even in an oxygen atmosphere a sudden increase of CO2 may have no effect on the biosphere. Instead of sending probes to other solar systems, It may be easier to build large telescopes that take advantage of the gravitation lensing of the host star. Considering we can already determine the composition of extra-solar planet atmospheres, an advanced alien civilization could possibly have enough telescopic resolution to map the earth. Considering the Earth has hosted life for at least 3 billion years,… Read more »
Torbjorn Larsson OM
Member
Torbjorn Larsson OM
May 10, 2010 2:50 PM
not the sort of thing tea bagger types are eager to fund. Sorry, I’m not familiar with that brand of politics (IIRC US terms correctly). My point, which I believe you acknowledge here, is that probes are expensive. That will work against them under any politics or economics if there are alternatives. At the end of it all we might wonder if all our observations of the universe, study and theoretical understandings are just howling at the moon. I think that is too pessimistic. The reason we, as I believe, don’t know enough to answer Fermi’s question with something approaching a testable theory (outside perhaps of the closest stellar neighborhood) is that we haven’t tried to mount the… Read more »
Torbjorn Larsson OM
Member
Torbjorn Larsson OM
May 10, 2010 2:55 PM

Note on my last comment: Of course when colonies expand beyond the solar system they will no longer be loosely knitted, as distances would prohibit sensible economics. They would be colonizing ships, literary if inhabiting asteroids, sailing to distant harbors.

Lawrence B. Crowell
Member
Lawrence B. Crowell
May 10, 2010 7:12 PM
You basically need a better lens, or more gravity, for such a short focal length. The effective Lorentz contractions are not enough to get much serious lensing action. The problem with the theme of the article is that is about as probable as our sending Bracewell probes and the like. The one book in the Bible which does say a lot about the human condition is Ecclesiastes. Essentially the problems we face today are the same as they ever were, but we do manage to magnify them and make them more complicated. “There is nothing new under the sun” Ecclesiastes. In some sense it is sort of true or en francaise “Plus ca change, plus ce l’meme chose.”… Read more »
Uncle Fred
Member
Uncle Fred
May 10, 2010 10:12 PM
@LC Interesting idea about Bracewell Probes. I like this idea as it seems to offer the most probable chance of comparing our knowledge with a present or future civilization. I imagine such a machine would need to be artificially sentient, so as to maximize the potential of 2-way communication. I would be particularly interested if such a sentience was programed to look for common knowledge (i.e. some variant of math/physics). However, I am unsure any Bracewell type probe would make it a priority to share its knowledge with us. Moreover, this posting reminded me of such Prime Directive styled episodes as Voyager’s “Friendship One.” In that episode the database of a deep space probe shared nuclear and antimatter… Read more »
Duncan Ivry
Guest
Duncan Ivry
May 11, 2010 12:15 PM
@ Lawrence B. Crowell An interesting quote: “There is nothing new under the sun”. As far as I can see remarkably many comments on the web show the attitude expressed in this statement (by the way, I don’t say, you are sharing this attitude). If I compare our modern human world — differentiated societies, advanced sciences, sophisticated technologies, resourceful arts — with the human world, say, 2.000, 5.000, and 10.000 years ago, then I see many — really many — things being completely new. I don’t want to insult anybody, but it would be ridiculous saying — as just two examples –, that the theory of relativity and quantum mechanics are only some kind of repetitions or rearrangements… Read more »
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