[We asked Hugo-winning SF author David D. Levine to tell us about an interesting event he and several other notable SF writers participated in just before this year’s Worldcon. –pnh]
The week before Denvention 3, I attended Launch Pad, a workshop in modern astronomy for science fiction writers held in Laramie, Wyoming. It felt like a science fiction convention with thirteen writer guests of honor, eight science guests of honor, and no fans. It was an intense, thrilling, highly educational experience, exhausting and mind-expanding at the same time.
The idea behind Launch Pad is Gernsbackian: getting good science into popular fiction as a form of public education and outreach for NASA. SF writer and University of Wyoming astronomy professor Mike Brotherton managed to get a NASA grant to fund this workshop for five years, of which this was the second. All the attendees’ expenses were paid, including transportation to and from Laramie, housing in college dorms, and most meals—though we had to pay for our own drinks (no alcohol on the taxpayer’s nickel!). Attendees were chosen from the pool of applicants based on the size of their existing audience, their demonstrated interest in science and astronomy, and the diversity of the group.
I was truly honored to be selected for this year’s workshop, which also included Nancy Kress, Steven Gould, Laura Mixon, Jay Lake, David Marusek, Mary Robinette Kowal (who went on to win the John W. Campbell Award the following week), and copy editor Deanna Hoak. We formed a cohesive and supportive community of writers, chatting about craft and business over meals and working together to comprehend the challenging subject matter.
And it was a tremendous challenge. It was as though each of us had one of those little turkey timers in our foreheads. One by one, depending on our science backgrounds and current intellectual capacity, heads filled up and the timer went pop!, indicating that particular head was unable to absorb any more information in that particular lecture. Some people’s timers went off right at the beginnings of some lectures, others lasted until late in the week. But all of us eventually reached saturation. Even a hard science fiction writer’s brain has its limits.
Mike Brotherton led off with a lecture on the scale of the cosmos, including a viewing of Charles and Ray Eames’s short film Powers of Ten. Astronomers, we were told, prefer to use numbers between 1 and 10 (sometimes up to 100) and use different units (kilometers, astronomical units, light-years, parsecs, megaparsecs, redshift units) as necessary to keep the numbers in that range. I was surprised to learn that, using satellite-based telescopes, we can now use parallax to measure the distances to stars up to 1000 parsecs away.
Discussion of the size of the universe got a little weird and metaphysical. The observable universe is 28 billion light-years across, because the big bang was 14 billion years ago and we can’t see anything farther back than that. However, the universe as a whole is much larger and definitely doesn’t have an edge, but may or may not be infinite. But, we sputtered, how can the universe be bigger than that? Wouldn’t that require moving faster than light? The answer is that space itself can expand faster than light, which isn’t the same as objects moving through space (or information being transmitted through space) at that speed.
Pop! went the mental turkey timers, all over the classroom.
Jim Verley then gave a lecture on public misperceptions of astronomy, starting with the film A Private Universe which reveals that even Harvard graduates can’t explain why we have seasons (one popular false explanation is that “the Earth is closer to the sun in summer”) or why the moon has phases (“it’s the shadow of the Earth falling on the moon”). Watching a crimson-cloaked Harvard professor trying, and failing, to explain the seasons was cringe-inducing.
The basic problem is that students don’t come to school as blank slates. Many people have incorrect private models in their heads, which must be identified and confronted on an individual basis before the student can really internalize the standard model. Even if they learn the standard model well enough to pass the test, if the private model isn’t explicitly displaced it may return years later after the standard model has been forgotten.
This is why we were here. If we can get the science right in our science fiction, it increases the chance that young people will have the correct model in their heads before they get to those college astronomy classes.
Mike Brotherton started off the second day with a comment to the effect that observational astronomers are night owls, while theorists are the ones who schedule 8am classes. He then gave us a lecture on the electromagnetic spectrum.
Almost everything we know about the universe outside of the Earth (except for some moon rocks and space dust) comes to us in the form of light and other electromagnetic radiation. He explained the relationship between frequency, wavelength, and the speed of light, and how light is broken into the spectrum by a prism because the speed of light in glass is lower than it is in air and varies according to the wavelength (the frequency stays the same, but the wavelength changes as the velocity of the wave goes down). Light is also a particle, of course, and the energy of each photon is determined by its frequency. This isn’t the same as the intensity of the light, which explains why you get sunburn from high-energy UV photons but no harmful effect from even a very intense green light.
Black bodies are theoretical objects that absorb light equally at all frequencies. When hot, these objects also emit light at all frequencies. The term “black body radiation” refers to the characteristic spectrum of such a body, which peaks at different frequencies depending on its temperature. The total amount of energy emitted also depends on the temperature, but to the fourth power—if you double the temperature (measured in degrees Kelvin, i.e. degrees above absolute zero) you increase the energy by a factor of 16!
Telescopes come in two basic flavors: refracting (lens) and reflecting (mirror). Reflecting telescopes are lighter and don’t have chromatic aberration (the red and blue fringes you can see on bright objects when you look through the edges of thick glasses like mine). Reflecting telescopes are also much easier to make big, and the bigger (in diameter) the better!
Modern professional telescopes use adaptive optics (tiny rapid changes in the mirror to compensate for atmospheric disturbances) and long-baseline interferometry (using several small telescopes to simulate a much larger single telescope) to achieve results nearly equivalent to space-based telescopes. However, space-based telescopes can see frequencies that are hard for ground-based telescopes to see through the atmosphere, including infrared and X-rays.
Adaptive optics is very cool. This technique was developed by the military about 20 years ago for getting good pictures of enemy spy satellites from the ground. The trick is to determine exactly what effect the atmosphere is having on the image so you can adjust the mirror to compensate, which requires having a known target above (most of) the atmosphere. So they use a laser beam to excite sodium in the upper atmosphere, just ahead of whatever you’re observing. That takes a pretty powerful laser: 50 watts. “What’s that in razor blades?” I asked, knowing that the number of razor blades a laser can slice through was once used as a measure of laser power. The answer: “A whole lot of razor blades.”
Jim Verley then led us through a hands-on exercise in which we peered at glowing tubes of several different gases through diffraction gratings, trying to identify each gas by comparing the spectral lines we saw with charts of several common elements. The exercise was very cool and a lot of fun (I have never seen a band of pure teal light before), and clearly showed us that the difference between theory and practice is always smaller in theory than it is in practice. We were particularly amused by the fact that the two different references we had sometimes showed what looked like completely different spectra for the same material. I was reminded of the classic “Electron Band Structure In Germanium, My Ass“.
Next up was Jerry Oltion with a couple of exercises in back-of-the-envelope calculation. He started off with an easy one: how much does a cow weigh? Step one: posit a spherical cow of uniform density. Yes, he really said that. The next question was “If we want to build an accurate scale model of the solar system, including Pluto, inside this 30′ long classroom, how big is the sun, how large are the planets, and how far are the planets from each other?” Jerry brought an assortment of spherical objects to help visualize this. (“I have the minor planets here in a bag .”)
We started off with a 12″ beachball for the sun, which makes the Earth a 1/10″ diameter BB 100 feet away; Pluto would be an insignificant speck nearly a mile away. From there we made the sun smaller and smaller (softball, tennis ball, ping-pong ball, marble ) until we finally got down to a 0.09″ mustard seed. At this scale the solar system (well, not the diameter of the solar system, but all the planets strung out in a line to scale) just fits in the classroom. Earth is a tiny speck 9″ away, Jupiter is smaller than a grain of salt at 45″ away, and Pluto is an even tinier speck 30′ away. There’s a whole lot of empty space in the solar system. Furthermore, at this scale Alpha Centauri A and B would be a pair of mustard seeds 20-30′ from each other 31 miles away!
The final exercise was to view the space station docking scene in 2001 and determine its gravity, using the equation v²r = g. The station rotates once per minute and, based on the heights of the people visible in some windows, is about 150 meters in radius. This means the circumference is about 1000 meters, so v is 1000 meters per minute, which yields a simulated gravity about 1/6 of Earth’s—the same as the moon (though the people inside move as though the gravity is Earth-normal). The very tidy numbers suggest that Arthur C. Clarke told the special effects guys exactly what to do.
The second day ended with a party at Mike Brotherton’s house, where we chatted with members of the UW astronomy faculty and saw the Milky Way and a couple of meteors. Being able to see the Milky Way from an average suburban house pointed out why we had come to Laramie for this workshop: it is high in altitude (thus above some of that darn atmosphere), generally dry and clear, and well away from big city light pollution.
Day three started off with a talk by Jerry Oltion about amateur astronomy. In the astronomy world, “amateur” is not a pejorative. Many pro astronomers are also amateurs, and many significant discoveries have been made by amateurs. Even if you have an 80″ scope at your day job, you might want to have a smaller scope in your garage because you can use it whenever you want and point it wherever you want.
Cheap telescopes often brag about how much they magnify, but the important thing for astronomy is not to make the image bigger but to make it brighter, so as to see objects too dim for the naked eye. For this reason, size counts, but the diameter is more important than the length (ahem). One danger of amateur astronomy is “aperture fever”—the desire for a bigger and bigger scope. It used to be that you had to grind your own mirrors, but machine-made mirrors are now good enough that hand-grinding is no longer necessary, though it’s still a rite of passage.
Why do bright stars in astronomical photographs appear to have four points? The eye of the beholder: it’s due to diffraction effects from the “spider” that supports the secondary mirror, which usually has four supports.
Mike Brotherton then gave a high-speed, high-density lecture on “everything you always wanted to know about stars.” A star’s properties are uniquely determined by its mass and chemical composition. Bigger stars burn hotter and have shorter lives.
People have been studying stars for a long time and there are many lingering remnants of earlier ideas. For example, information about stars used to be presented in charts in color order, from blue to red. Now that we know that blue stars are hot and red stars are cool, the X axis of these charts now represents temperature rather than color, but they’re still shown with the blue (hot) end on the left, so the temperature decreases as you read across! And the reason the spectral classes are in the peculiar order OBAFGKM (Only Bad Astronomers Forget Generally Known Mnemonics) is because they were named in order of strength of the hydrogen line in their spectrum (A = strongest, O = weakest) but are now listed in order of temperature (we now know that O stars are the hottest and M are the coolest). What happened to C, D, E, H, I, J, and L? They turned out to be duplicates, and were dropped.
Stars can be graphed on the Hertzsprung-Russell diagram with spectral class (temperature) on the X axis and luminosity (total amount of light output) on the Y axis. Most stars fall in a roughly diagonal band from hot-and-bright (upper left) to cool-and-dim (lower right), which is called the Main Sequence. This is not a temporal sequence! Most stars spend most of their life moving slowly across the width of this band.
Stars are born in areas of dense gas and dust. Something, such as a shock wave from a supernova, causes an area of the gas to begin to condense. These protostars begin in the lower right of the H-R diagram (cool and dim), getting hotter and brighter as they condense, but after a while their luminosity actually starts to go down even as their temperature increases, because they are getting smaller. Shortly after fusion begins they blow off their surrounding cocoon of dust and gas and become visible to us; this transition is called the “birth line” on the H-R diagram. The star continues to condense and stabilize, throwing off jets of material which may in turn shock the interstellar medium into new protostars, until it eventually settles down on the main sequence at a point determined by its mass.
When a star reaches the end of its life, what happens depends, again, on its mass. A typical star will move off the main sequence toward the upper right of the H-R diagram (becoming a giant star, which is cooler than it was before but gives much more light than a main-sequence star of the same temperature because of its larger surface area), then blow off its outer envelope, leaving a white dwarf remnant in the lower left (hot but small and dim). A smaller star cools to a brown dwarf; a larger star explodes violently as a supernova.
Time to look at the actual sky again. After class we drove up to the Wyoming Infrared Observatory (WIRO), which despite its name is used only for optical observation these days. When we arrived the sky was overcast, but we toured the facility, which consists of a very ordinary-looking small house with a giant dome attached. Inside that dome was the telescope, a bus-sized spindly contraption with an eight-foot mirror on one end and a three-foot cubical box on the other. We gawked and took lots and lots of pictures. The moment when they cranked open the roof was just awesome. I asked the two grad students staffing the observatory if the thrill from that low thrum as the slit opens to the sky ever goes away, and they just smiled and shook their heads.
Now we waited for nightfall and hoped the clouds would clear. We ate our dinner, talked with the astronomers, amused the cat (Nu Boötes, successor to the previous observatory cat Mu Boötes), played cards and chess, and enjoyed the view. The view from the mountain was spectacular, looking like a Star Trek matte painting as the sun set. Just then it started to drizzle and they had to close the dome.
Oh well, I thought, at least we got to see the telescope. But right around the time we were getting ready to bail, the clouds parted. Huzzah!
We headed back into the dome to see the astronomers charge up the instrument cluster with liquid nitrogen to reduce noise. Then we were shooed back out, presumably to prevent being crushed as the giant machine turned in the pitch dark of the dome.
I spent the rest of the evening alternating between the control room, where I saw live pictures of the Ring Nebula on computer screens and asked lots of questions, and the gravel lot outside, where the Milky Way came out and we gawked at the night sky. We had a pair of night-vision goggles, through which I saw a satellite and the Andromeda Galaxy. I got back to the dorm around 1am.
Very, very cool.
Day four, a Sunday, started out with a nice hike around Turtle Rock in Vedauwoo, which offered spectacular views, a little rock climbing, and pleasant temperatures.
After lunch we met in the university’s small planetarium, which is rare in that it is still equipped with a traditional optical “starball” (AKA “giant ant”). Modern digital projectors are more flexible, but there’s something about the smooth motion and ineffable “directness” of the old-fashioned starball that makes it a more engaging way of learning about the night sky. Unfortunately, optical starballs are difficult and expensive to maintain; many features of this one were not working. Our host Jim Verley gave a very entertaining talk about both the workings of the planetarium and night sky basics.
Mike Brotherton then continued his talk about stars. More than half the stars in the galaxy are members of binary (or larger) groups. Stellar evolution in binaries is complicated and depends on the two stars’ relative masses. For example, in a pair that consists of a big star and a small star, the big star will blow up into a giant star first, and its smaller companion will have the opportunity to pull away some of its outer atmosphere. If the smaller star pulls away enough mass, it may become the bigger member of the pair. Later, when it becomes a giant, the white dwarf remnant of its formerly-larger companion may pull away some of its mass in turn. In some cases the larger star may completely absorb the smaller, in as little as a couple of months.
If one member of the pair is a white dwarf, the matter coming into it from the other star is whipped into an accretion disk due to conservation of angular momentum. This infalling gas is incredibly hot, and may outshine the original star and emit large quantities of X-rays. Hydrogen may also settle on the surface of the white dwarf in sufficient mass to begin fusing. If this occurs, it ignites all over the star at once in a spectacular explosion: a nova. Because this only affects the surface of the star, it may happen again and again.
Our sun will eventually (5 billion years) expand to a red giant about the size of Earth’s orbit. The Earth will move out slightly, because the sun’s mass will have decreased by then, but it’s really an academic question whether it’s broiled by falling into the sun’s atmosphere or merely toasted by proximity. Either way it’ll be a mighty warm day. Eventually the outer parts of the sun’s atmosphere will be blown away (comparatively gently) and the core will settle down as a white dwarf.
Massive stars (25 solar masses or more) burn hydrogen at the core for about 7 million years, then helium for 500 thousand years, then carbon for 600 years, then oxygen for six months, then silicon for one day. At this point the star resembles an onion, with a silicon-burning core surrounded by an oxygen-burning layer surrounded by a carbon-burning layer, and so on. Silicon fuses to iron, but iron doesn’t fuse at all. When all the silicon is used up, the core collapses, beginning a reaction that destroys the star in a massive explosion: a supernova, which produces a flood of neutrinos and creates all kinds of heavy elements. Every atom in the universe that’s heavier than iron is the result of a supernova explosion.
Supernovas are rare, occurring about once every hundred years per galaxy. Most of the supernovas we see are in other galaxies. This is a good thing, because a nearby supernova (within about 100 light-years) could kill us with the neutrino flux.
A supernova blows off most of the star’s mass into space, creating such spectacular structures as the Crab Nebula, and leaves behind a small dense core. If this stellar core is less than 3 solar masses it becomes a neutron star, with all the protons and electrons smashed together to create an incredibly dense solid mass of nothing but neutrons. As the core collapses, angular momentum conservation makes it spin faster and faster, with a period of a few milliseconds. The same collapse amplifies the magnetic field by a factor of 10 to the 12th. Pulsars (objects that pulse rapidly in the optical and radio bands) are believed to be rotating neutron stars in which the magnetic pole is not aligned with the rotational pole. Every time the magnetic pole points in our direction we see a pulse. It may be that all neutron stars are pulsars, but we can see only the ones where the beam from the pole happens to shine on Earth. Some pulsars wobble as well as pulsing, indicating the presence of planets.
If the core is greater than 3 solar masses, its gravity is greater than the forces within the atom and collapse continues past the neutron star phase. There is no known mechanism to halt the collapse of a compact object of more than 3 solar masses. It keeps collapsing down to a single point: a singularity, or black hole.
Escape velocity from the surface of an object of given mass goes up as the object gets smaller and denser. The point at which the escape velocity is equal to the speed of light is known as the Swartzchild radius. If the object is any smaller than this it doesn’t matter. The Swartzchild radius is the “event horizon” beyond which nothing can ever be detected. This radius scales linearly with the mass of the object (3km for an object the mass of the sun, 30km for an object of 10 solar masses a galactic-core black hole of 1.5 billion solar masses has an event horizon as big as Saturn’s orbit).
Black holes, it is said, have no hair. This means that they lose almost all of the characteristics they had before they became black holes. The only characteristics left are mass, angular momentum, and (maybe) electrical charge. Even though black holes do not emit anything, we can detect them by their effects on objects around them, or by “gravitational lensing” (a distant object changing its brightness or apparent position as a black hole passing in front of it warps its light).
Because of general relativity, a clock falling toward a black hole will appear to an outside observer to slow down, and stop as it passes the event horizon. At that point the light from the clock is red-shifted, meaning that it gradually fades from view. (This was the point in the lecture where my mental turkey timer went pop! so I can’t explain why this occurs.) From the clock’s perspective the event horizon is undetectable; it’s like driving past the point where you don’t have enough gas in your tank to return home. However, in practical terms, long before it reaches the event horizon the clock will be torn apart by tidal forces. This phenomenon is called “spaghettification” because the object is “stretched into spaghetti,” but this image is far too tidy in reality the object is ripped to pieces because every piece of it is being pulled either up or down relative to every other piece.
Mike Brotherton started off day five with a lecture about galaxies and cosmology. Almost everything we can see with the naked eye at night is in our own Milky Way galaxy (this is, apparently, its actual name—I expected it to have an official scientific name like Galaxy Number One or something, but no). One exception is the Andromeda galaxy, which is barely visible as a hazy “star” near Cassiopeia.
Stars in the galactic disk have nearly circular orbits, while “halo” stars outside the disk have highly elliptical orbits. The orbital speeds of stars in our galaxy and others show that the mass of a galaxy is distributed throughout the galaxy rather than mostly concentrated in the center. The speeds of the orbits tell us that there is a lot more mass in each visible galaxy than we can account for through visible objects such as stars. But what does this mass consist of?
Could this dark matter be ordinary dust and gas? No. We know the abundance of “baryonic” (ordinary) matter in the universe from studying the Big Bang, and there isn’t nearly enough to account for the invisible mass.
Could it be WIMPs (Weakly Interacting Massive Particles) such as neutrinos? No. Although neutrinos don’t affect normal matter much, they do affect it, and we have performed experiments (using large quantities of dry cleaning fluid) that show there aren’t enough of them either. A theoretical WIMP called the “axion” has been proposed but never observed.
Could it be MaCHOs (Massive Compact Halo Objects) such as black holes and brown dwarfs? Maybe, but probably not. We can detect these objects through gravitational lensing, and we don’t see enough such events to account for the missing mass. Could it be that we are simply wrong about gravity? No. MoND (Modified Newtonian Dynamics) seemed plausible until 2006, when new studies of the Bullet Cluster were released.
I must say that before Launch Pad I was both confused and skeptical about the very weird stuff called “dark matter.” (Note: not to be confused with “dark energy,” which we talked about later.) I didn’t understand why this strange non-interacting stuff had to be invoked when it could just be, well, matter that was just dark. But the Bullet Cluster was for me, you should pardon the expression, the smoking gun.
The Bullet Cluster (http://en.wikipedia.org/wiki/Bullet_Cluster) consists of two clusters of galaxies that have recently passed through each other. We can see the hot gas of these two clusters (which is normal matter) using X-ray telescopes, but we can also find their centers of mass using gravitational lensing of the galaxies behind the cluster. The two centers of mass are farther apart than the visible gas. This tells us that the majority of the mass in the two clusters does not interact with itself or with the matter of the clusters in the same way as normal matter. (This includes a very helpful video simulation.)
Okay. Deep breath. Stretch your legs and reset your turkey timers. More weird stuff ahead.
Many galaxies have spiral arms. If you look at a picture of a spiral galaxy it looks just like water going down the drain, or a hurricane, and you think you can tell which way it is rotating. The actual rotational direction is the other way! Spiral arms are, in fact, standing waves in the interstellar medium. At the leading edge of these waves (the inside edge of each sickle-shaped arm), new stars are born as the interstellar medium impacts the shockwave. The bigger, hotter stars burn out first, so the leading edge is brightest, fading away to dimness as the brightest newborn stars burn out or fade away. An individual star may pass through several spiral arms in its lifetime.
We can measure the distance to other galaxies by using Cepheid variables and type Ia (pronounced “one-A,” not “iyaah”) supernovas—these are white dwarfs in binary systems that collapse when they accrete too much matter from their companion. We know exactly how bright they are because they explode immediately upon reaching a certain mass. These “standard candles” tell us that distant galaxies are moving away from us with a speed proportional to their distance.
Those galaxies aren’t moving through space, as any fule kno it’s space itself that’s expanding. This expansion is happening everywhere, but it’s only visible in intergalactic space because at smaller scales the force of gravity is greater than the expansive force. You’ve probably heard the expansion of space described as being like dots on the surface of a balloon that’s being inflated? The galaxies are like stickers on that balloon: they get farther apart, but not bigger.
By studying tiny fluctuations in the three degree Kelvin background radiation that is the echo of the Big Bang, we can determine the initial conditions of the universe and determine that the total mass of the universe is almost exactly what is needed to make the universe “flat,” meaning that it will neither expand forever nor contract in a Big Crunch: the expansion will slow down and stop at some point. But there isn’t enough matter, even including dark matter, to account for this flatness, and when we measured the rate of deceleration, we got a surprise: it wasn’t slowing down at all, it was speeding up!
It turns out there’s a “cosmological constant” in Einstein’s equations, which was thought to be zero, but if we set it to a negative value it explains both the accelerating expansion of the universe and the missing mass. The missing mass is the mass equivalent of this weird anti-gravitic energy. We don’t know what this “dark energy” is—it has never been observed directly—but it makes the equations balance.
It may be that the cosmological constant itself is increasing. If it stays the same, the universe expands so fast that all other galaxies will eventually fade from view: the “Big Empty.” If it is increasing, it will eventually get big enough to overcome atomic forces and everything in the universe will be torn apart: the “Big Rip.” For now, though, it’s less powerful than gravity and other forces, meaning its effect is only visible at the very largest scales.
After that cheery reassurance we went to the computer imaging lab where we got a talk by Chip Kobulnicky on imaging in astronomy. Raw images from the Wide-Field Planetary Camera on the Hubble space telescope look awful. They consist of four rectangles (three large, one small) with big visible seams between them, speckles of noise, and cosmic ray streaks. Scientists and technicians have to do a lot of processing to make them look all pretty and colorful. We also got some hands-on experience using a program called ds9 (astronomers are SF fans, who’d have thunk it!) to combine the R, G, and B images of the Ring Nebula that were taken at WIRO on our field trip the other day into a single color image.
The day ended with a talk on SETI by scientist/philosopher Jeffrey Lockwood. This talk was a bit of a surprise as we spent the whole time talking and writing about what messages we, as writers, would send to aliens, ignoring questions of transmission mechanism and language. It was an interesting writing exercise, and thought-provoking, but was so different from the hard science focus of the rest of the week that some of us felt kind of whiplashed.
One of the exercises I wrote during this session was a message to express the importance of “pattern” to humans while simultaneously encoding the Fibonacci sequence:
It happens again.
Why does it happen again?
Can we predict what the next instance is?
By observing phenomena, we learn about the universe and learn to predict events.
We find patterns and recurrences in all kinds of physical phenomena, from molecules to stars, simple to complex, insert and alive.
Once we have discovered a pattern, we can build devices, craft new experiments, build more knowledge on top of what we have already learned, and even begin to make changes and improve our environment.
We finished the evening on the roof of the physics building, looking at binary stars, globular clusters, the planet Jupiter, and various satellites (including the International Space Station) with night-vision goggles, binoculars, and two very nice amateur telescopes.
Day six began with an entertaining talk by Ruben Gamboa on computing in astronomy. Modern astronomy is all about computers—the days of staring through eyepieces and developing film in darkrooms are over. Computers are used for controlling equipment, automating repetitive tasks, organizing data, and building scientific models. Computers are very good at boring tasks like looking for comets and supernovas, so most comets these days are named after discoverers like NEAT (Near-Earth Astronomical Telescope) rather than Hamner-Brown. The next generation of survey telescopes will generate 30TB of data per night (that’s half a Library of Congress or 1/20 of YouTube). Google is working with LSST to build a system to manage all this data.
Jerry Oltion then gave a loose, interactive talk on humans in space and astronomy in fiction. A few tidbits:
- The human body does not explode in vacuum. One NASA volunteer was exposed to hard vacuum in a space suit test accident; he passed out after 14 seconds (his last conscious memory was of the water beginning to boil on his tongue) but they restored normal atmospheric pressure quickly and he survived just fine.
- Space capsules and space stations tend to stink badly, and this is a serious problem. Although your nose eventually stops smelling the stink, it’s still psychologically oppressive.
- Air in free fall does not convect, which means that everything that heats up has to be cooled by fans; the space shuttle is loud inside.
- Sex in space has almost certainly happened, but Jerry thinks that the reason nobody has talked about it is that it’s not all that good. In space your nose stuffs up, you smell, perspiration doesn’t evaporate, your blood pressure goes down, and experiments on the Vomit Comit have shown that even hanging onto each other and achieving penetration is a hassle.
- Stan Schmidt warns writers that it is extremely unlikely to have a habitable planet around a star with a name. (Named stars are all bright, and the bright stars tend to be too hot or too large for Earth-like life.)
Mike Brotherton’s post-doc Rajib Gauguly then gave a highly technical talk on quasar absorption lines (“studying gas you can’t see using light that isn’t there”). After six days of this we had the background to understand a lot of it. But I think my mental turkey timer may have broken for good somewhere in the Lyman Alpha Forest.
We finished up with a brief talk on the search for exoplanets (i.e. planets orbiting other stars). There are 228 known exoplanets around nearby stars, some as small as 5 times the mass of the Earth.
So that was Launch Pad. I came out of it exhausted, intellectually challenged, stimulated, and excited. I got a couple of new story ideas and I’m sure more will bubble up from my subconscious over the next few months. I made some wonderful new friends, ate way too much, and saw things I might never otherwise have seen.
Your tax dollars at work.