Friday, June 28, 2013

Twitter, Twitter, little star!

Well, this week's thriller on the news wires, as in the BBC report we saw, is that a star called Gliese 667C has at least three (count 'em) planets orbiting it within the proverbial Goldilocks  'habitable zone' in which life can occur.

What the sky might look like from Gliese 667C; BBC
 Habitable zone?
This is the region where temperatures ought to allow for the possibility of liquid water,although no-one can say for sure what conditions are really like on these planets...
The planets would need an atmosphere to sustain liquid water on their surfaces, but at a distance of more than 200 trillion km, there are no means currently to determine what the precise conditions are like or whether life would have any chance of establishing itself.
Nonetheless, Dr Tuomi believes M-dwarf stars are good candidates to go hunting for potentially habitable worlds.
The fact that these three planets could have liquid water "...single-handedly demonstrates that low-mass stars can be hosts of several potentially habitable planets," explained one of the investigators, helpfully. We've seen this many times before, cosmologists using 'life' to mean 'life as we know it', the marketing criterion by which to get discoveries of orbiting rocks into the mainline news.

Whether these planets have any atmosphere is a trivial detail that current research can't answer.  In part, this is because the planet is a mere 22 light years away (about 200 trillion kilometers!).  The star is about a third the size of our sun, and the planets about 3 times the size of the earth.  These planets, the story hopefully enthuses, have annual orbits of 28, 39, and 62 days.  Because the pseudo-sun is smaller and cooler (it's what is known as an M-dwarf star), planets can be closer to it than the earth is to our sun and life still may have evolved there, and they can orbit fast without being singed beyond recognition.

Now, finally!  We have planets that might plausibly (and hence the news writers and scientists would like us to assume, must) have life.  And just imagine what it's like!
Twitter, twitter, little star!
Life  on Gliese 667C  would be quite a whirlwind.  Let's take 40 days as the typical orbit.  Days and nights, and years, would (literally) race around like cars in the Indy 500.  A message as long as this would take a week to write.  For poor students, a 15 earth-week (say, 100 days) semester would take 3 Gliese 667C years!  Students would reach retirement age shortly after graduating.  And don't get too fond of your pets.  With a 10-year lifespan, kitty would only last 400 days--about one earth year!

Indeed, circling this little star so quickly would have taught everyone long ago to communicate fast.  We hypothesize that Twitter was invented on Gliese 667C, and somehow transmitted to earth.  With the world, so to speak, passing by with such dizzying speed, one would not wish to dawdle over every correspondence.  A long-time earth friend you've known for 5-10 years would be the equivalent of a Gliese 667C friend you met only a couple of hundred days ago.  We'd all have to wolf down our food to prevent noticeably aging during a single meal.  And nights would not last long enough for even a single 90-minute dream cycle!

The implications of life in the fast-orbit are dizzying.  It seems almost impossible to imagine.  And contemplating life on Gliese 667C raises further very serious and perhaps even more profound questions, that lead us (ever the skeptics!) to doubt claims or hints that life really does exist on Gliese 667C.  Here are some of the problems. 

Is life in the fast-spin possible?
  • Life heavily depends on the annual cycle of seasons.  For example, mating takes place in the cold season when many creatures are hibernating or pupating, so that young are born in the spring when their prey are hatching.  Because embryos take time to develop, if the year is too short, they will be born at the wrong time relative to their food sources.
  • Similarly, many plants shed their leaves to refresh their growth after an off-season.  Deciduous plants require fertilization from insects who are active (and hence whose larvae have matured) when the leaves are new and the plants are in flower.   It's true that on earth bees and plants and other animals have different gestational times from fertilization to maturity, but winters need to be long enough for that to happen, and that takes months rather than just a few days.  The short days and weaker amount of light from this lesser star would also play havoc with chloroplasts' needs for enough light to achieve enough photosynthesis in the brief daytimes, so trees might not be able to grow big enough nor produce enough nutrient energy to support their leaves, limbs, roots, flowers, and seeds.  Bad news for the squirrels, bees, bugs, and even woodpeckers.  Apples won't have maturing time to become, well, actual apples.  They'll just be tiny runts.
  • At the same time, the lesser energy may yield far fewer thunderstorms and hence  fires to clear the vegetation for forest health.  And this in turn may also not provide enough tropical rainforest to absorb enough CO2 or release enough oxygen as needed for other life on the planets.  And the growing seasons might be so short that only bonzai trees could survive, providing no sustenance or low- (or high-) hanging fruit for insects or mammals.
  • We don't know whether these exoplanets have atmospheres or not, but if there's life then of course they must.  But whether the 'air' would be dense enough for bird or even insect flight, or pollen dispersal, is highly problematic.  There must of course be sufficient oxygen for breathing as well as to provide a shield against dangerous cancer-causing UV radiation from Gliese 667C.
  • Sea life depends, at least for animals, on buoyancy, which requires that the salt content of the exoplanetary seas be suitable for algae, crustaceans, fish and sea mammals.  Likewise, the evolution of land life from sea life requires sufficiently strong  (but not too much!) gravity for support by bony structures, so the expansion onto land would allow mobility for searching for prey or escaping predators.
  • Even the climate makes a difference.  Spring runoff and the like provide fresh water when more animals are active.  Tectonic (geologic) activity is needed to shape the land and sea and its interface and even to provide some minerals and building materials for life.  But would it be fast enough, or too fast?
We have just outlined a few of the requirements for life on these new planets, and you would be able to imagine others along similar lines.  For example--do you think it's just trivial?--if the land, atmosphere, climate and so on were not appropriate for tree life, there would be no paper for books and hence no advanced civilization to evolve.

Of course, we're just spoofing here.  When cosmologists and the media (including sci-fi writers and Hollywood) talk about 'life' elsewhere, they almost always mean 'intelligent' life and even human-like life.  Talking about 'habitable zones' reflects this.  Yes, carbon, oxygen, water and the like are vital to life here, and could be important elsewhere.  But it is only a paucity of imagination, and a penchant for self-promotion, that leads to reports like this being treated as more than just the discovery of a few rocks in space.

Life need not be as we know it, or perhaps we have so provincial an understanding that the word itself really means our kind of molecular activity.  What other forms of self-perpetuating activity might exist, in or out of 'habitable zones', who can say?

Gliese 667C is a very close star to us, as these things go.  For starters, there are 56 stars known to be less than 17 light years from the earth (e.g., Wikipedia 'List of nearest stars').  These are, of course, stellar systems as dead as doornails as far as we can tell.  We get no radio rock music emanating from them.  So we must go farther afield to find our nearest neighbors. 

But even as close as 22 light years, which is much closer than most other stars even in our own galaxy (which is about 100,000 light years across) not to mention other galaxies, even if there were human life on Gliese 667C, and even if they were, unbelievably, in the same fleeting fragment of their existence to use electromagnetic (i.e., radio) means of distant communication, and even if they had some sort of 'language', and even if they were curious about what aliens might exist out beyond Gliese 667C, just to set up communications would take lifetimes (44 years just to exchange one message, and how many cycles to learn to read each others'?

Let's think about this.  There will be no Rosetta stone signaling from space--signals with translation into an earth language.  Decoding ancient (simple) cuneiform tablets, like the famous Mycenean  Linear B from the ancient Mediterranean world (see below) took a lifetime and more of scholarly work to understand and translate.

Linear B: Wikipedia
So, suppose, for example, we detected some dot-dash code-like electromagnetic emanations from Gliese 667C.  To establish recognized communication, first to show the 'signal' wasn't some sort of astrophysical artifact, much less to translate and actually converse, would it take, say, 100 messages, 50 each way?  Well, 100 messages means 2200 years, longer than it's been since the classical Greek era! And of course even the NSA (who may already have secretly recorded the emanations!) couldn't decode things that fast!

Actual travel even at high but imaginable speeds (assuming light is the fastest way to go and approaching it would require ginormous amounts of fuel energy), a one-way trip to Gliese 667C would take longer than hominids have existed.  So even contemplating contact, even with a nearby star, even having human-like intelligence (if that's not just a self-flattering term!), verges on putting us in a mind, much less a time, warp.

Is there life out there?  We've written about this before here on MT.  Given that there are on the order of billions of galaxies, each with billions of stars and hence likely multiple billions of rocks orbiting around, it would seem implausible that there is not a variety of forms of 'life' all over the place.  But while it is entrancing to muse about, it is to a great extent not even a scientific question to ask.  It is musing, it's philosophy or even religion perhaps, but it's not science. 

ET; The Guardian
We already have Hollywood to deal with this sort of thing, better than reality can. Rather than hawk the public to pay for it via 'research' grants, let the movie makers -- the dream-weavers -- bear the cost.  In a world of competing needs, it is not proper for scientists or media to hint, obliquely or otherwise, that discoveries such as this, interesting as it certainly is, is more than confirming in a specific instance what we've already long known: there are lots of orbiting rocks in the universe.


Anonymous said...

The problem is that planets such as these is that they are probably tidally locked, with the same hemisphere always facing the star. The sun lit hemisphere would be subject to intense blasts of radiation from the star. So even if there is an atmosphere and liquid water, it is not yet clear whether life could evolve on planets such as these.

Ken Weiss said...

Peter Edmonds (whom we don't know) tweeted that we had made a minor errror in this post, because we used the star's name to refer to its planets, as in the source of detected emanations (properly, the planets have been given their own star-specific designation).

Anne Buchanan said...

Thanks for catching that, Peter!

Ken Weiss said...

Yes, thanks. We don't attempt to keep up on all the aspects of planetary science (that is, we hardly know any of it!). But our post was a kind of spoof on the Life! discovery hints that are always part of NASA and others' marketing or publicizing patterns.

Most seriously, the issues would be what we would count as life, and what its chemical basis would be (would it have to be based on sequence-specific aspects of carbon-based polymers?), or what is 'intelligence', etc.

All other things being equal, would ETs think of a sheep as 'intelligent life'? They should. Or do we need to be hyper-restrictive and mean only humans-with-language-calculus-and-radios?

David Evans said...

"a one-way trip to Gliese 667C would take longer than hominids have existed"

That's wrong. There are credible designs for a nuclear fusion pulse rocket to reach 1/10 of light speed, which would make the trip in 220 years.

Ken Weiss said...

Well, this is so exciting to learn about, that I think it deserves a new post of its own!

I may try that (but I hope you're not kidding, and I hope this will be cold fusion, so the thing doesn't go bang in the night).

Holly Dunsworth said...

What a roaring post! Thanks for all these things to ponder and thanks for giving me an idea about how to steer the conversation towards something worth talking about when people ask me about the future of human evolution.

EGallant said...

A fun perspective, thanks Ken. I'd love to shake hands with the inventors of Twitter, we'd be best friends in under 100 days. It would be worth the 1/10 of light speed trip, but only if the planet was covered in bonsai trees (too cool to contemplate). Plus, tiny runt apples, a must see/taste.
Astrobiology, I honestly love the subject. Holly, I have a book for you if you want it: Weird Life, The Search for Life That is Very, Very Different from Our Own, by David Toomey

James Goetz said...

Hmm, we should try to send radio communication to the planets in system Gliese 667C. If one of those planets developed intelligent life that developed sophisticated radio technology, then we might here back from them in 44 years.

David Evans said...

Not cold fusion, and it definitely does go bang! I was thinking of the Orion design

which uses a large number of small nuclear explosions. I see that I had misremembered the speed - it's only 1/30 of light speed - but there are other more refined ideas.

Ken Weiss said...

We're taking your thoughts and running with it on Monday. It's something fun to think about.....even without more refined ideas!