Thursday, December 29, 2011

Monday, December 19, 2011

A description of a toy store

The doors opened into a large circular room with a high-domed ceiling.  The room was all built of wood, and was old enough that trails through the room had worn away from centuries of children's shoes.  Two staircases curved around either side of the room, leading up to a balcony.  Around the walls were inlaid scenes from children's books-- Treasure Island, Beatrix Potter, The Wizard of Oz, Alice, perhaps two dozen in all.  These were made from thin slices of chalcedony, malachite, turquoise, jade, and the like, cut to shape and chosen individually because of the surface pattern. These, too, were polished only near the bottom where children could reach, and especially near the faces. The staircase banister was carved in an Art Nouveau style, all leaves and gently diverging curves.
This room, and all the rooms in the store, were full of toys, to the point of being almost crowded.  They were organized by some kind of theme that only the owner knew-- kites, sleds and flying toys in one section, blue things in another. I can't begin to describe everything that was there.  What I remember mainly are glimpses, and by this point only the glimpses that I've remembered many times before remain.

In the corner of the main room by one of the curving staircases stood a suit of polished full plate mail and helm, just the size of a child. The metal had been ribbed in such a fashion that it was very strong, despite being pounded to incredible thinness to reduce its weight. By adjusting the straps and through clever design of the joints, it would continue to fit a child almost to adulthood. I am not sure what kind of metal it was made of; it gleamed like silver but was even whiter to the eye.

Floating near the cupola roof (painted to look like the night sky, with constellations and tropic lines marked out in gold leaf), were flying machines of all types and sizes.  Sailing ships suspended from balloons bumped against robotic armored coelacanths that swam through the air like some Devonian sea.

Through the stained-glass doors at the back of the room was a library. The bookshelves were tall enough that a walkway had been built halfway up to give access to the higher shelves.  In the center of the room stood a large dead tree that had been lacquered and carved so as to create dozens of places that were comfortable for reading.  Smaller branches of the tree ended in tiny electric lights in the shape of cherry blossoms on adjustable stems that gave off warmth as well as light. One of the books I pulled down was a pop-up selection of tales from the Arabian Nights.  The pages themselves were made of brass, and the act of turning a page wound a spring inside that animated the cutout tin actors.  Each page opened into what resembled an opera stage, with layers of flat scenery from front to back. The book had a strong metallic smell that recalled the taste of blood on my tongue.

A castle, built of real stones and grey bricks the size of Pez candy, sat under the display window. It was furnished with dollhouse furniture (some of it from quite the wrong period) with drawers that opened to reveal tiny cooking utensils, or the Queen's jewels.  The blacksmith's shop was especially impressive. Surrounding the castle were thousands of toy soldiers from the Napoleonic era, all hand-painted, complete with working tiny metal cannons that used small firecrackers to fire rubber cannonballs.

There were dolls dressed in dyed Japanese silks, satin, velvet, fur and taffeta. One type of dolls had joints contrived so that they could only take natural poses, and would hold any pose fairly tightly. If you took the hand of one and pulled it in some direction, the rest of the joints of the body naturally moved so that it looked as if the doll were reaching towards the point the hand had been dragged to, and the other arm moved in such a way as to retain balance. On a high shelf stood a Japanese samurai doll made of a rich red wood.  By clever manipulation its limbs could be rearranged and it would take the form of a Chinese war vessel with ribbed sails like dragon wings.
In the topmoset of the drawers was a box labeled "Steam Man of the Prairie." In the box was a doll resembling the Tin Man from the wizard of Oz. When a small candle was lit and placed on his back, he would walk along dragging a wagon behind him and sending up puffs of water vapor with the sound of repeated sighing. (His hands were firmly attached to the cart, and I doubt he could have balanced without it.)

There was a portable, folding artist's desk, well-used, and stained where paint had been brushed off the edge of paper pinned to the surface.  Hidden compartments could be accessed by sliding secret panels, revealing soft pencils, kneaded erasers, papers and canvas, watercolors, pastels, oil paints, a wide array of brushes, a compass and many other art supplies.

In a small side room were Christmas decorations, the only part of the store that wasn't actually for toys. It smelled of pine and cinnamon. One ornament in particular I recall: it was a delicate filagree of spun silver, framing a silvered, partly covered bowl that was tilted forward inside. Through a hole in the top of the bowl, by some trick of optics, a winged angel appeared to hang in midair, lit from behind by a dazzling halo.  What I remember best of all was the particular startled expression on that angel's face.

There was a large Chinese cabinet, with a screen of carved dragons. In its numerous drawers were all kinds of magic tricks.  One was a wand of yellow ivory, carved with intricate symbols and nested spheres.  It emitted some kind of heavy gas (supplied by a removable canister) that burned with a blue flame. If you held it over a table and tipped it a specific way, flames would spread in a growing puddle about a half inch above the table's surface. The flames strangely gave off no heat.  Another drawer contained a mechanical dragonfly with eyes made of cut garnets, but I didn't see whether it could actually fly or just flap its wings.

There were stranger toys, too, that I hardly know how to describe. One of them was a kind of oversized helmet attached to a microscope. It looked like it had been built around 1930 of largely cast iron parts. When you slipped under the helmet, you were surrounded on all sides by projections of the microscopic slide. Each hand controlled one probe, and foot pedals would cause you to soar around the scene.  To enhance the effect, variable speed fans blew wind in your face as you flew from one place to another. Looking at leaves or microorganisms with this would have been fantastic enough, but on one of the slides, an entire miniature island had been built from tiny bits of moss, insect parts, and grains of sand, including ruined cathedrals and sprawling treehouses.

The back wall of the balcony was for board games.  Most seemed to be unique handmade games, but some were familiar: there was a copy of Cathedral, I recall, which struck me as a little out of place because I had seen advertisements for it. One of the board games was in fact a type of treasure map, and following its instructions would lead you to a series of clues around the landmark buildings in the city of London that pointed to a the location of a mazelike key and a buried chest.  What was in the chest was a mystery, though the game hinted that it was something precious and indescribably ancient. The centerpiece for this section was a mechanical chess game on a raised platform, like an altar. The chessboard formed the top of a box about six inches high, filled with small gears and rods.  A placard said "D-- W--- watchmaker 1867." Indicator arrows on the sides allowed you to select the location you wanted to move a piece to, and each time a square was selected, those pieces which could move there would turn their heads to look at it.  If you then tipped one of these, it would move to the square and attack, swinging its tiny arm and sword. The defeated piece retreated off the board, whirring and ticking.  After checkmate, a music box would play, and the winning King and Queen would waltz around the board while the other pieces stood at the sides and turned their heads to watch. Before a game the box required quite a bit of winding of a handle on the side.

It would take quite a while to tell you the rest of it: the clockwork sauropods, the marbles that shone like stars, the collapsible fort, the musical kites-- and my very favorite of all, the toy that I actually brought home, the Friendly Mammoth...

Tuesday, December 6, 2011

Kepler 22b

Kepler has discovered a planet in the habitable zone of its sun-like star. It has a 290 day year, and a temperature of 22C, assuming a greenhouse effect similar to Earths (though with a thicker atmosphere, it is probably much hotter.) The planet has a radius 2.4 times that of the earth. This probably means that it has significant amounts of hydrogen in its atmosphere and has a deep ocean on its surface, covering all the land in miles of water. It's probably better to think of it as a warm Neptune than another Earth.

A few other facts:

  • It is about 600 light years away in the direction of the constellation Cygnus.
  • Its star is 25% cooler than our sun, but the planet orbits 15% more closely than Earth, so it works out temperature-wise.
  • There are conflicting reports about the surface gravity.  It is definitely higher than Earth, but the exoplanet catalog lists 4.84g, while Phil Plait estimates 2.4g, so I'm not sure what to believe.
  • Kepler has found another 1000 planet candidates since the last update in February. They've been confirming the Kepler finds with Spitzer, and found that all the ones they've checked so far were real,  so the error rate on Kepler detections is probably very low. Of these, I would estimate they've found more than a dozen new candidates that are at least as good as the five near-habitable ones they announced in February, but they haven't given any details about these yet. The conference is still ongoing, though, so there may be an announcement this week.
  • Here is a nice summary image of the confirmed planets found so far by all methods: 

Monday, November 14, 2011

Dr. Crane's Monologue

They want to be punished, Batman.
They want it very badly, and this is why--
because the alternative is that there is no such thing as justice.
The alternative is a mad world.

These criminals, they believe in hell.
They believe in a lava-filled pit
peopled with monstrosities
that torment those who break the rules
They believe this because the alternative--
that someone could get away with something,
permanently and with no repercussions ever,
get away with something--
is too awful for them to contemplate.

That demon is you.
They have to believe
that behind the weak, bumbling justice
wrapped up in technicalities
and its own corruption,
there is a relentless justice
that will sweep down in the night
and exact due pain.
You are the angel of destruction,
the shadow that passes over in the night.

You've called the criminals superstitious,
but that isn't quite right.
It's not superstition, but religion.
You can see that, can't you?

You wear the mask
thinking it will make them afraid of you.
I am an expert on this subject, so you should pay close attention.
If you wanted to make the criminals afraid,
you would act like a disease,
or like a tornado.
It is arbitrariness they are afraid of,
not that the wicked will be punished for their sins.
When that happens it only reassures them.

You can understand, right?
If they allow themselves to believe,
even for a moment, that a lie is possible,
they will never be able to trust anything again.
It will be as if the world ended
as if their parents were killed
in meaningless silence

There are only a few,
like you and the Joker and myself
who know the truth.
We are intimate with the truth.
We have felt it.

It is lies all the way down.

Monday, October 24, 2011

On games and recreation

I read about new videogames as they come out.  It's not on purpose, it's just that in the places I read they tend to come up.  The games seem to all have one thing in common: battle. And I don't like it.
Don't get me wrong.  I like explosions.  I love shows of power.  There is nothing I love to watch in a movie more than a good sword fight. I go to museums to look at armor. Let's face it-- my job is designing war robots.
And it's not the gore, either.  Seeing a computer animation of someone's guts, or a rotting corpse, gives me about the same feeling as seeing gum stuck under a desk I am sitting at.  Mild disgust, I suppose. I don't like gore, but it's just because it's ugly. I can't think of computer enemies as real.
The problem is the enemies distract me from my main purpose in a game. The enemies are like mosquitos, who annoy you until you manage to swat them away. I don't mind conflict in a story, but I wish it were something deeper and richer than erasing the things that bother you.
I think about my favorite games as a child.  They fall into two categories: flying games and worlds to explore.
Dragonstrike and Wing Commander were very similar in every way except that one was fantasy and the other science fiction.  In both games, you flew a series of combat missions, accompanied by friends who might die along the way. I did care about the story. The most important point was the flying, having that freedom to move through the world. In both games, I developed a technique to get rid of enemies.  I would fly as fast as I could in one direction, so that they would follow directly behind me.  Then, knowing exactly where they were, I would flip around and tag them before they could change course. What I liked about it was that it always worked.
The exploration games were Ultima VI and VII, Indiana Jones and the Search for at Atlantis and the Last Crusade. These games had hand to hand combat, but only if you couldn't figure out another way.  My favorite strategy was to carry around barrels so that I could set up a barricade, and fire in range weapons. It was just a way of getting rid of the mosquitos. what I liked was how vast the world was.  If there had been nothing to defeat, just mysteries to solve, I think I would have been as happy.
Two fun games that I've found recently were Crayon Physics Deluxe and Scribblenauts. Both games give you almost complete freedom to explore.  In Crayon Physics, anything you draw takes on physical properties. In Scribblenauts, any word you type appears as an object in the game.
What I would like to see is this kind of freedom combined with a rich, beautiful world to explore.  It's cool that they can make realistic modern cities for games like Arkham City or Grand Theft Auto, but most real cities are kind of ugly. I want to go somewhere beautiful, and not have to fight anyone when I'm there.

Wednesday, October 5, 2011

Jobs in Ten Years

In order for computers to generate compelling content, they must have a model of what humans find interesting or beautiful.  The only way to get this model is by measuring how interesting humans find particular images.  In the old days this was done by measuring ratings, but it was found much more effective to measure cortical response to images directly.  This can be done so quickly that it can take place even before conscious awareness takes place.  The Interest workers spend (a government mandated no more than) eight hours a day wearing a skullcap, watching movies that look something like Koyaanisqatsi sped up by 50 times.

Prediction markets are now big business, attracting both individuals and corporate algorithmic models. An intrader pursues up-to-the-millisecond news (largely through harvesting social networking updates) about a particular topic of interest, whether it be sports, celebrity babies, local politics, or box-office returns, and translates that news into what amounts to bets on the likelihood of these events happening.

The advent of brain scans able to recognize mental imagery has led to the ability to record dreams and imagined events.  While a few prefer the unedited content, most of these dreams are heavily edited to provide a semblance of story.  The technique has also influenced more mainstream filmmaking. Professional dreamers sometimes use "lucid dreaming" techniques, but purists prefer dreams directed solely by the subconscious. Being a professional dreamer is a lot like being a professional artist; very few make any money at it, but for some it is a calling. Ability to form mental imagery varies widely; 15% of the population are found to generate no mental images of any kind. It has surprisingly little effect on everyday abilities.

Do you have any other suggestions?

Friday, September 30, 2011

Ender's Game Movie

I'm so excited about the upcoming Ender's Game movie!!!!  A few things people have said make me a little nervous, though. Apparently:

  • The kids in battle school all have psychic powers from being so smart, like telepathy and starting fires
  • Valentine isn't the sister anymore, but the love interest, and she's like a karate champion
  • There's a scene where Ender decides he's going to break all the rules at battle school, so he puts on a leather jacket and sunglasses and they play "Bad to the Bone" in the background.
  • Bean is now the comic relief, with a lot of dwarf-throwing jokes
  • Instead of launching the Dr. Device, Ender now wins through concentrating hard on the power of love
  • Ender now has a CG alien pet that hangs around and says things in a funny accent (voice acted by Eddie Murphy)
  • M. Night Shyamalan rewrote all the dialogue
  • All the children in battle school are now American, but there's diversity because one is a jock, and one is a nerd, and one is a preppy, and one is a goth
  • Ender's punny catchphrases whenever he defeats someone
  • The formics now look like normal bald people with insect wings, and their queen is played almost exactly like Morgan Le Fay in the Merlin TV movie, including her loyal henchman and evil 1960s eye makeup
  • The battle room scenes aren't in zero-G but in a regular gym, because Nike wanted to do product placement

Sunday, September 25, 2011

Ars Hermetica

My brother and I have been discussing creating a new game.  The game would be a type of tabletop role-playing game, like Dungeons and Dragons. But rather than just being set in a magical version of the medieval world, the game itself would pretend to be an artifact from that world. What if role-playing games were invented by alchemists in 1200, instead of Gary Gygax et. al. in the 1960s and 70s?
Here are a few aspects of the game we've discussed:
The play would occur within a "memory palace" invented by one of the players.  The Ars Memoria was a classical technique for memorization that involved creating an imaginary city, and populating it with fantastic images, creatures, and monuments, in order to learn something by heart. It became associated with magic during the middle ages.
Encounters would be resolved by various divination techniques.  These could include dice, but geomancy, cards, sheep knuckles, or astrology are also possibilities.  In this period, even games like chess and nine-men's morris were invested with mystical significance and divinatory properties. The players would have supposed  that the events being described were not fiction, but actually occuring in some ethereal world, and that by sympathetic magic, moving tokens about would allow the players to bring about their ends in that other world.
The "monster manual" would be a variation on the medieval bestiary.
The magic system, maps, and so forth would be based on real sources.
The manuals that you would use to play with would all be made to look like ancient books. (Ideally it would all be in Latin, but I think we would have to compromise, here.)

Playground games

I got a couple of books on playground games and children's oral culture for Christmas, and it occured to me that I might write down some of the oral culture that I still remember. These were from Redford, Michigan, between the years 1980-1987, when I was five to twelve years old.

Rock-paper-scissors, mostly just played as a game for its own sake, rather than to pick who got to do something.

Counting out games
Eenie-meenie-miney-moe, catch a tiger by the toe, if he hollers, let him go, eenie-meenie-miney-moe.
(I understand this may have developed from the special counting terms use by shepherds in Scotland.)
 Inkadink a bottle of ink, cork fell out and you stink. Not because you're dirty, not because you're clean, just because you kissed a girl behind the magazine.
Bubble-gum, bubble-gum in a dish.  How many pieces do you wish?
All of these rhymes were using archaic language: we didn't say "holler," we said "yell." We didn't use bottles of ink.  We would say, "how many pieces of gum do you want?"

Songs, mostly parodies using a known tune
Jingle Bells, Batman smells, Robin laid an egg.  Batmobile lost its wheel and the joker got away, Hey!
On top of spaghetti, all covered with cheese, I lost my poor meatball, when somebody sneezed.

Clapping games (I never learned them, but the girls would play them often.)
Hello operator, give me number nine, and if you disconnect me, I'll chop off your behind the frigerator, I found a piece of glass...

Four Square
The most important rule of four square was that the person in the highest position got to call out all the rules: he was King. He or she could make up whatever rules he wanted, and many had specific names, like "bobbling" meant bouncing the ball up and down in your hands. In a way it was a game about making rules for games.

Mostly paper airplanes and fortune-tellers

What do you remember learning from other children, rather than at school, or from books?

Friday, September 16, 2011

The Fly

There was a short-lived cartoon called Sectaurs in 1984 that got me thinking about what the proper way is to map people onto flies. I was quite fond of the action figures.  Basically, an accident causes a kind of half human, half-fly creature to emerge.  For some reason, the shock of this idea really caught my imagination at age 9. I still remember thinking some of this through on the long school bus ride home.
One of the first things I realized about it was that the concept of "average" I had been taught was the wrong way to go about finding out the height and weight of the monster.  Suppose a person is 100x as big as a fly.  Then the monster, I reasoned, should be 10x as big as a fly, and 10x as small as a person. The concept I was groping towards was the geometric mean.
Later, as I learned more about evolutionary development (as a kid I also found pictures of fetal development fascinating and grotesque in exactly the same sort of way as crossing people with bugs) I learned that the eyes of a human are not developed from the same part of the embryo as the compound eyes of a fly. Human eyes are, morphologically speaking, an extension of part of the brain. Fly eyes, on the other hand, have more to do with skin and hair cells.
The other interesting fact from evolutionary development I learned more recently. In humans, our spinal column is in our back.  In insects, it runs down the belly.  But they are caused by the same sets of genes at the beginning stages of embryonic development.  Basically, the vertebrate body plan and the insect body plan are upside down from each other: our backs are their bellies.  I can't see how including these facts in the next remake of The Fly would make it any less successful at being a horror movie!

Here's a reference for that last bit about the dorsal/ventral flip.

Monday, September 12, 2011

Advice for a high school senior

In general:
You will soon have an enormous amount of freedom to determine the course of your life.  This is more freedom than you will know what to do with. You have to understand that the world is not set up to help you or harm you.  Society is like the laws of nature: it simply doesn't care about you.  If you want something out of life -- love, or money, or happiness, or success -- it is your job, your constant job from now on, to figure out how to get that from the system. You've got to wrestle those things out of the ground.
Now this having been said, you also should realize that it's all life. All the good parts of life and the bad parts are all mixed together.  We all make terrible decisions with lifelong consequences and have brilliant accidents and friends die and children are born. That's just the kind of thing life is.  Don't beat yourself up about it too much.
You need to make plans, and you need to work and think and fight harder than you ever thought you would need to to make them happen.  But no matter what happens, good or bad, experience it -- accept it --  instead of wishing so hard that it was something different that you are angry about it all the time.

About jobs:
As nearly as I can tell, no one has ever gotten a job worth having by going to a jobs website and applying for something that fit their qualifications. It may have happened, but I've never heard of it. Instead, what happens is this: you get to know people, who find out that you are reasonably clever and not prone to yelling. You let them know you are looking for a job.  When their other friends need to hire someone, your friends mention that they know a guy. This leads to an entirely different sort of interview.  The first kind of interview they assume they won't hire you, and they don't.  The second kind of interview they assume they will hire you and they do.
This is why you should do internships and volunteer and write open-source software and generally get yourself into rooms with grown-ups who can see you are a competent sort of person. It's a random and unpredictable process so try to get in as many of these situations as you can.

Thursday, August 11, 2011

Monday, July 25, 2011

LDS Animal Research

The Foundation for Animal Research and Church Education has just posted the latest issue of their journal, detailing the research they have been performing over the last few years.  If you're in the Provo area you can drop in and see their lab!  A few highlight papers:

" Homeostasis of frogs in water with a temporal temperature gradient"

"Simian fruit grasping reflex through a narrow channel"

"Crab king-of-the-hill behaviors in bucket conditions: a retrospective survey"

Do you have any favorites to add?

Thursday, June 30, 2011

The Mountains of the Moon

Early depictions of the moon show it as a colorful body, but at least dating back to the 1969 moon landing, the moon has been entirely black and white. Some believe this desaturation was caused by the television cameras used at that time; others believe the cause is related to the belief systems of ghosts.

Monday, June 13, 2011

Unenforced rules

When I was in junior high school, the lunchline had a no-cutting rule. But this rule was routinely flouted, and friends would often let their friends cut in line.  The problem got so bad that those of us who obeyed the rule would often have trouble finishing lunch in time.
I realized something general about the situation, and I think it is a little bit of wisdom: unenforced rules are a punishment on people who obey rules. If you create a rule but don't enforce it, you are attacking those who are inclined to be on your side, and helping those who will get away with whatever they can.  If this goes on too long, people will start to switch camps. Far better not to have a rule at all, if you are unable to enforce it consistently.

Thursday, May 12, 2011

Perpetuum Mobile

"Gary's mod" is a modification of a video game engine to include some aspects of mechanics. By exploiting the fact that you can build a box of water with an open bottom where the water doesn't all pour out, the author of this video built a perptual motion machine in that game world.

In AI we often model our problems as "energy minimization." You can turn that around and say that nature solving an energy minimization problem is acting artificially intelligent.  That's why perpetual motion machines are interesting, even though they never work: no matter how clever we are, nature always figures out ways to make them not work consistent with the laws of physics. Nature always "outwits" us.

Sunday, March 20, 2011

The country where blood is taught

As I was journeying through that country, I met an old man who told me of his home in a distant province.  In that land, they believe that certain diseases are dangerous ideas that flow not from one mind to another, but through the blood.  And just as in our own country we conspire to tell children stories so that when they are adults they will be able to recognize the signs of a widespread conspiracy, so too in that province they spread a harmless amount of diseased blood into their children to protect them against the full disease.  But he says that a certain part of the population has caught a disease of the mind which causes them to be frightened of this process, and so leave their children vulnerable. I suggested to him that the young children could be taught about the spread of disease in schools, so that they would be able to withstand the spread of the fear when it was carried to them as adults, an idea which had never occurred to him.

Monday, March 7, 2011

The origins of VX Modules in the 1700s

I've been trying to trace the origins of the theory of VX modules, given the obvious connection between VX experimenters and artificial creativity research. Take a look at the following graph (from Google's n-gram server, on the search term 'VX'):

Apparently the VX community was more active in the late 1700s than it is was as recently as the 1980s! If we take a look at some of the titles from that period, it's obvious that these are actually work with the foundations of geometric and analytic Froebinius encabulators and tetrodyne fluxions rather than what we would today consider to be directions of serious research (such as the ennervation of Mornington Crescents), but still, the topic was clearly leading to the modern approach:

A treatise on Fluxions: or, an introduction to mathematical philosophy

Sectionum conicarum elementa: novo methodo demonstrada

The Doctrine of Ultimators: containing a new acquisition to mathematical literature naturally resulting from the consideration of an equation as reducible from its variable to its ultimate state: Or a discovery...

Thursday, February 3, 2011

More about Kepler Worlds

Most of the news you will see is about the 6 planet system that NASA played up.  But they did find the earth-size planets in the habitable zone of the M dwarfs like I thought. The information about these has not yet been published as far as I can see, but has a preview of the forthcoming paper.  The best candidate is a .6 earth mass world (under reasonable assumptions based on it's radius being .89 earth radius) with an expected temperature of 332 Kelvin. That's 138 Farenheit-- a little hot, but these worlds are likely tidally locked, so have a side facing away from the sun which is much cooler.  So the twilight zone on the planet may actually be okay for earthlike life. That paper will also talk about many other planets in the habitable zones, including some gas giants.  If there is a way around the radiation problem, the moons of these worlds could, like Pandora or Endor, be habitable moons.
UPDATE: Here's the overview paper.
The planet discussed above is called KOI 326.01. KOI stands for Kepler Object of Interest.  326 is the number of the star, .01 means the first planet detected around that star.

This is the information about the star KOI 326:

Kepler object of interest #  326
Kepler Input Catalog #   9880467
Kepler magnitude    12.960
Photometric precision   189
Right ascension   19.11040
Declension    46.7835
stellar temperature   3240
log(gravity) of star  4.90
stellar radius    0.27
stellar mass    0.21

You can see that this star is about a quarter the size of the sun.  You can also see where it is in the sky. I'll have to look around to see if I can find the distance in light years.

Monday, January 31, 2011

Kepler habitable worlds around M-dwarf stars to be announced on Wed.

I was excited about the discovery of Gliese 581g a few months ago.  Well, it turns out that planet may have been a statistical glitch and not actually exist.  But that's okay.  Because on Wednesday, the Kepler mission will announce their results from the first six months of observation (the release of the data has been delayed for a year from when it was captured because of researcher politics).
A planet like Earth around a star like our sun would need to have an orbit like Earth's to be habitable.  By habitable, I mean not too hot (like Venus) or too cold (like Mars). But M dwarf stars (red dwarfs) are much smaller and cooler than the sun, so a planet getting the right amount of heat would be much closer, so that it's year would be about 1 earth-month long.
Kepler is observing 2460 M dwarf stars. (From this paper.) Of those stars, between 1 and 3 percent will have their solar systems lined up in the right way so that the planets will pass in front of the star. That makes about 50 systems. Of these, not all the systems will have a rocky planet with a gravity near our own in the habitable zone. But it seems reasonable to suspect that at least 10% of them will.  Since Kepler has been observing for six months, all 5 of these planets will be observed crossing their star at least three times. M dwarfs are more variable than the sun, so the data is more noisy, but the more transits are observed, the more sure we can be that a planet really is in the place we think it is.
So my prediction is that on February second, the Kepler mission will announce not just one, but five potentially habitable worlds.
These worlds are likely tidally locked, so one side is always facing the star and the other is always facing away, in the same way that the moon is tidally locked to the Earth, so that we always see only one face. So I would say that the most likely candidates to actually be habitable (by Earthlings) would be ones with a little higher gravity than earth, so that they can sustain a thicker atmosphere better able to distribute heat around the planet.  Since the greenhouse effect would make such planets hotter on average, we should choose the ones that are receiving a little less heat from their stars than Earth gets from the Sun.

Friday, January 14, 2011

Winter and Summer

(With apologies to Mr. Whelan.)