The Science of Battlestar Galactica
Page 14
Multiple star systems with more than two stars usually consist of a collection of binary pairs, or of binary pairs with one lonely star without a dance partner.
A trinary star system is statistically much less likely to form than a binary. A quadruple system is significantly less likely than a trinary. We know of a few star systems with six stars, but so far we know of none with twelve, which leaves us with the problem of how to pack multiple planets around a single star.
Computer orbital dynamic simulations tell us that 50 percent to 60 percent of binary star systems can form terrestrial planets within their habitable zones. But which habitable zones? Is the terrestrial planet orbiting only one of the two stars, largely unaffected by the gravitational perturbations of the companion star? Or is the planet in a distant orbit around both stars much in the way Proxima Centauri is around Alpha Centauri A/B?
Sol’s Goldilocks Zone extends from near the orbit of Venus to near the orbit of Mars. With the right atmospheres, both could be habitable. So each star in a multiple star system could potentially have two or three habitable planets within the habitable zone of one of the stars’ common center of mass. The Earth/Moon system has the largest satellite mass compared to the primary in the solar system, so high that a number of scientists think Earth and Luna form a binary planetary system. In the series Caprica, the colonies of Gemenon and Caprica are configured this way, revolving around each other as they orbit their star. The fairly sizeable Tauron presence in Caprica City also makes it plausible that that planet is in the same planetary system.
Yet it is still a very-low-probability event that a star system, even a multiple star system, would have twelve planets suitable for colonization. Nevertheless, we can apply known observable phenomena from physics and planetary science to postulate the scenarios in which this may occur. For the home of the Twelve Colonies we probably want a multiple star system consisting of Type F, G, or K stars having multiple planets orbiting each star. It’s not impossible, but it is at this point that we must remind ourselves (1) that the hand of the divine has shown itself throughout the run of Battlestar Galactica, and (2) of the first rule of The Science of Battlestar Galactica.
Name: Kobol
Type: Terrestrial
Kobol, the homeworld of the Colonials, is a beautiful planet of oceans, clouds, mountains, lush vegetation, and a nifty holographic planetarium in a temple. It’s also a planet in a stable orbit around a stable star, in a temperature zone where water can exist as a liquid, and it’s loaded with the chemicals of life. This makes it a definite rarity in the galaxy; not one of the so-called terrestrial exoplanets discovered at the time of this writing is very Kobol-like.
How did Kobol come to be this way? Chances are, if it formed the same way Earth did, its atmosphere was brought by comets. But comets bring very little breathable oxygen; they tend to load up on things like carbon dioxide, water, methane, and ammonia. Why does Earth have a human-breathable atmosphere when its neighbors have atmospheres of carbon dioxide? Planetary scientists think that about 50 million years after Earth formed, it was struck by a planetoid roughly the size of the planet Mars. The impact blew off Earth’s first CO2-rich atmosphere, and the resulting splatter coalesced in space to form our Moon. Subsequent comet impacts and volcanic eruptions gave Earth its second atmosphere, which Earth’s first bacteria could breathe. For a planet to be habitable, some mechanism has to keep the carbon dioxide content in its atmosphere low. This would be true for a planet like Kobol, as well as both Earths and New Caprica.
Name: New Caprica
Type: Terrestrial
New Caprica is a cold, barren, barely habitable world in the middle of a nebula. The planet might be located at the outer edge of its star’s habitable zone, or the surrounding nebula might absorb too much sunlight to warm the planet—either way, only about 20 percent of the planet around the equator is suitable for colonization.
“Suitable” is a fuzzy word. A year after landing, New Caprica City is, at best, a shantytown. Just because you can set foot on a place and possibly raise a few crops doesn’t mean that a planet has what is necessary to sustain a population, let alone the resources to let that civilization grow and develop. Like postattack Baltar himself, New Caprica seems to be a land of “just getting by,” rather than a place of real growth.
One interesting thing is that New Caprica has an adequate amount of plant life, but no large animals are ever shown. Is the planet too cold for land animals to develop? Is it too young for land animals to have evolved? Or did the producers just not want to pay to both invent, then visualize, New Caprican cows and horses?
Name: Ragnar
Type: Jovian Gas Giant
Ragnar is a gas giant planet orbiting one of the stars of the Twelve Colonies. The Colonial government has placed a service and resupply anchorage (basically a space station in an impossibly low orbit) in the atmosphere of Ragnar. The location was chosen because the planet’s radiation keeps the base hidden from Cylon DRADIS (Direction, RAnge, and DIStance). In the miniseries, Commander Adama discovers that Ragnar’s radiation can, in time, damage the “silica pathways” leading to the brains of humanoid Cylons like Leoben.
Where other planets may have an atmosphere, a Jovian-type planet like Ragnar is an atmosphere. Most of it is, anyway. Except for a rocky metallic core, five to ten times Earth’s mass, buried deep within the planet’s center, a gas giant consists mostly of hydrogen and helium with traces of heavier molecules like methane, water vapor, and ammonia.
If a Jovian planet is mostly atmosphere, how would we measure its radius? Scientists have agreed on the “one atmosphere” rule: as you descend to deeper levels of a gas planet, the pressure of the overlying gases will naturally increase. At some point the pressure from the overlying gas is the same as the atmospheric pressure at sea level on Earth. At that point, measure the distance from the planet center, and you have just determined the “radius” of the gas planet. As with a solid planet, above the “radius” is the “atmosphere.”
Name: Maelstrom
Type: Jovian Ice Giant
In the episode “Water,” it was established that Galactica is able to resupply ships of the Fleet with water or fuel by piping these liquids directly from Galactica’s storage tanks into theirs. This procedure is called underway replenishment (UNREP). It’s efficient to pump supplies directly from one vessel to another, instead of ferrying supplies incrementally using Raptors, but it leaves the Fleet temporarily vulnerable—it’s nearly impossible for Galactica to maneuver when it’s physically connected to another ship.
In the episode “Maelstrom” the Fleet is UNREPing again. As fate may have it, the Fleet finds a natural DRADIS jammer that allows them to hide from the Cylons while vulnerable: the Jovian planet we’ll conveniently call Maelstrom. Maelstrom is intermediate in size and composition between Saturn and Uranus. “Ice giant” planets like Uranus and Neptune may have a solid core, but they are mostly composed of water, ammonia, and methane—compounds we’ve found to be common in comets. Hydrogen and helium are present in ice giants, but predominantly in the atmospheres.
All Jovian planets, gas giants and ice giants alike, have very powerful magnetic fields. When high-energy charged particles like fast-moving electrons become trapped and swirl within a magnetic field, they emit a form of electromagnetic radiation called synchrotron radiation. While it is possible to generate synchrotron radiation anywhere within the electromagnetic spectrum, from radio waves to gamma rays, the synchrotron radiation from Jovian planets tends to be in the radio and microwave portion of the EM spectrum. What types of technological devices send or receive information using radio or microwaves? Wi-fi networks do, as do satellite communications, electronic garage door openers, satellite TV and, yes, even radar (and presumably DRADIS). The ice giant planet Maelstrom was one huge natural source of electronic countermeasures.
Name: Dead Earth
Type: Terrestrial
It used to be such a nice place. Now parts of it loo
k like winter in the Asiatic steppes, while other parts of it look like a bad day in Brooklyn.
Saul Tigh on Dead Earth.
Yet did you notice that even in a bombed out, radioactive wasteland, life still clings tenaciously to whatever it can? Wouldn’t a postnuclear planet be absolutely lifeless? Not necessarily, although we can’t be absolutely certain.
In 1986, an accident at the Chernobyl nuclear reactor, 70 miles north of Kiev, sprayed radioactive particles over parts of Ukraine and Belarus. The Ukrainian city of Prypiat, population 50,000, was evacuated 36 hours after the accident, when radiation levels in the town had risen to nearly one million times normal background levels. Though still abandoned, Prypiat and the surrounding forest contain a thriving ecosystem—a bizarre, mutant ecosystem filled with albino birds and giant radioactive ferns, but thriving nonetheless. Like Dead Earth, the region is still too dangerous for people to reoccupy, but it takes more than just a little radioactivity to wipe out all life (see chapter 14, “The Effects of Nuclear Weapons, or How the Cylons Can Reoccupy Caprica after a Few Days but Not Dead Earth after Two Thousand Years”).
Name: Algae Planet
Type: Terrestrial
When the Colonial Fleet arrived at the algae planet they found an ocean full of photosynthesizing cyanobacteria (commonly called algae), a thriving ecosystem (developed just far enough to have developed algae and land plants), an atmosphere rich enough in oxygen to allow people to breathe unassisted (and, presumably, to provide an ozone layer), and a huge temple with an artistic rendering of an event that hadn’t happened yet.
This is approximately the state of evolution that the Algae Planet was in when the Colonial Fleet arrived. Here on Earth, the development of green autotrophs led to an explosion of other life forms, specifically creatures that ate the autotrophs. This eventually led to the colonization of the land, because non-autotrophic life forms (a.k.a. “animals”) now had access to these floating bags of high energy food. Perhaps the algae planet would have followed this same line of development, but since it was subsequently destroyed in a supernova explosion, we’ll never know.
Satellites
Name: Ice Moon
Type: Ice Moon
According to Colonel Tigh, most planets are just “hunks of rock or balls of gas.” But once you locate one of those planets—particularly the balls of gas kind—its moons are likely to be composed largely of ice, just like the one Boomer and Crashdown found at the end of “Water.” Icy moons are not rare—at least not in our solar system—and it’s reasonable to assume that icy moons, asteroids, and comets should be common in many types of planetary systems.
Of the nearly five hundred extrasolar planets, or exoplanets, discovered to date, most have been Jovian: Jupiter-like gas planets. Many of these orbit their parent star in extremely tight orbits, and are known as “hot Jupiters.” In Galactica’s desperate search for accessible water, these types of planets would be the easiest types of planets to detect from a distance, but could also be instantly ruled out—they’re located too close to their central stars for water to be in a solid state.
Though there are traces of ice on our own moon, the true ice moons in our solar system are found in the dim frigid realm of Sol’s Jovian planets. We’re therefore more likely to find similar icy moons in the middle to outer reaches of other planetary systems. There ices can condense around the solid body of a small moon. This further underscores an important point: what you call a “rock” depends upon where you are in the solar system. In the outer reaches of a planetary system, water ice is a naturally occurring crystalline substance, and is considered a rock by planetary scientists.
The three most well-known icy moons in our solar system are probably Europa, Enceladus, and Triton. Europa, the smallest of Jupiter’s four Galilean satellites, was a shock to scientists when they first saw it close up during the Voyager flybys in 1979. Instead of a rocky, cratered moon, the probes sent back images of a smooth, cracked world of ice. Subsequent space probes have helped us to determine that Europa almost certainly has a small iron core, a rocky mantle, and a subsurface ocean of liquid water, capped by a crunchy frosted shell.
The problem with such ice, from a Colonial Fleet standpoint, is that it almost never is pure H2O. Water on an icy moon in the far reaches of a planetary system, or orbiting a Jovian planet (or both), will almost certainly contain volatile contaminants such as ammonia, methane, or even other hydrocarbons like ethane. Fortunately, chances are that Galactica’s water purifiers will know how to remove methane and ammonia from the water. Small amounts of ammonia in the body are caused by normal protein breakdown. This ammonia is usually broken down into urea by the liver. People with liver problems, such as heavy drinkers, generally produce more ammonia in their urine than people with healthy livers. (Colonel Tigh, we’re looking at you.) Then again, who knows if Cylon livers work the same way. Since the Cylons have made improvements on the basic human design in areas such as strength and stamina, wouldn’t they have taken care of that pesky ammonia-in-urine thing? If so, there’s an interesting test to confirm if Tigh is really a Cylon—get him drunk, then check his toilet.
The good thing about such ice, from a Colonial Fleet standpoint, is that it almost certainly contains volatile contaminants such as ammonia, methane, or even other hydrocarbons like ethane. As we have seen, water, methane, ammonia, and a source of energy (in the case of Europa, that would be frictional heat caused by Jupiter’s gravitational pull) can, theoretically, combine to make the precursors of life. For Earthly scientists (and for Colonial fleets looking for algae-type foodstuffs), the most promising place to find extraterrestrial life in our solar system is not Mars, but rather Europa.
Name: Kara’s Orange Moon
Type: Titan-like Moon
Kara Thrace, her Viper in a flat spin and damaged beyond control, ejects and parachutes onto the surface of a small, barren orange moon. The atmosphere is unbreathable, and a thick layer of haze hides the surface from space.
Sounds a lot like Titan.
Slightly larger than the planet Mercury, Titan is the largest moon of our own planet Saturn. It is the only natural satellite in the solar system with a dense, stable atmosphere, and the only place outside of Earth that has large bodies of liquid on its surface.
Kara’s orange moon.
How does a moon come to have an atmosphere? The planet Mercury has more mass than Titan, and therefore more gravity. How can a moon like Titan have an atmosphere, and the planet Mercury not have one?
Mercury is hotter. At Mercury’s distance from the Sun, any gas atoms or molecules tempted to hang around the planet are heated by sunlight six and a half times more intense than at Earth. Those gas molecules heat up, speed up, and more readily achieve escape velocity. At Saturn, sunlight is 1/90th as intense as it is at Earth, nearly 1/600th as intense as at Mercury. Gas molecules don’t move very quickly, and Titan’s gravity has no difficulty hanging onto them in large amounts.
ORIGIN OF THE ALGAE PLANET
We’d just come to the point where we needed to get serious about how the rag-tag fleet would navigate toward Earth and he presented a whole PowerPoint presentation on space navigation, which gave us some ideas that the writers room twisted into “The Passage.”
—Bradley Thompson, Chicago Tribune Online Interview
You never know what small thing a good writer will latch onto. In a room full of writers, especially those as talented as those on Battlestar Galactica, a single offhand comment can turn into an episode. Or two.
Before season three, the writer Bradley Thompson phoned and told me, “We’re going to start getting serious about finding Earth this season. We need you to tell us what landmarks we have available to us.” I threw together a half-hour presentation that I gave to most of the writing staff, speaking of celestial phenomena and observables like stars, pulsars, star clusters, nebulae, and black holes.
After the presentation I was waxing philosophical with the writers Bradley Thompson and David Wedd
le. I wondered aloud, “Stars much bigger than Sol don’t live very long—bigger stars live by the motto ‘Live fast, die young, leave a good-looking black hole.’ It took life, the first algae, 800 million years to form after the formation of Earth. Stars much bigger than Sol live only, say, a billion years, not much longer. I wonder how many times in the history of our galaxy has life first appeared on a planet and barely had time to scream ‘We’re here!’ before the Sun goes BOOM!”
Isn’t that exactly what we saw in “The Eye of Jupiter” and “Rapture”?
While the existence of Titan’s atmosphere isn’t perplexing, its chemistry is. Mostly nitrogen, it contains a small amount of complex hydrocarbons ranging from methane (CH4) to propane (C3H8), along with traces of other gases like carbon dioxide, hydrogen cyanide, argon, and helium. The thick orange clouds covering the moon probably come from the breakdown of methane gas by ultraviolet light from the Sun, and that’s the problem. Ultraviolet light from the Sun, even the small amount available at the distance of Saturn, would completely break down all the methane in Titan’s atmosphere in a few tens of millions of years. Yet the methane is still there. How is that possible?
SERENDIPITY: A MANDALA-COLORED STORM
In the field of observation, chance favors only the prepared mind.
—Louis Pasteur
Serendipity. Look for something, find something else, and realize that what you’ve found is more suited to your needs than what you thought you were looking for.
—Lawrence Block
The hand of the divine may have been manifest throughout Battlestar Galactica, but occasionally it seemed to intervene in the production as well. The original plan was for the planet Maelstrom to have an extensive ring system like Saturn, in which the Fleet could hide while UNREPing. While the writers initially liked the idea, the attitude quickly turned to, “But didn’t we already do that in ‘Scar’?” Another way had to be found to hide the Fleet, and the convenient synchrotron radiation produced by a Jovian planet like Maelstrom proved to be just that. There was still a great reason to visit Maelstrom.