Launch Pad, Day Three: Kevin R. Grazier on Space Environment

To see more of my posts on Launch Pad, click here.Note: The schedule had Kevin's lecture today swapped with his lecture yesterday. Today is really space environment. Yesterday was actually gravity, newton, kepler, orbits.Mass in space:There is no mas sin space, outside of planets and stars, etcetera. That's why it's called space.Though strictly speaking, that's not true; there are about 16 atoms per cubic inch, on average. This is much less than in the vacuums we create in laboratories.The solar system is immersed within a local maximum (local fluff) which is, itself, immersed with in a larger, though still "local", minimum. A local bubble. When we talk about local fluff, we're talking about small changes in a very, very, very large vacuum. This mattes when we're looking through light years of it. Even though there's not much of it, it shows up.Our sun puts out a constant stream of particles. Among them are alpha particles, helium nuclei. There's a constant stream of material streaming off stars.But space is pretty empty.Sound in space:None. The medium is not dense enough.Strictly speaking, you could have sound in space if you had a really, really, really big explosion. In your stories, though? Not happening.Magnetic fields:Magnetic fields are created by moving, charged particles. Whenever you have a current, you have a magnetic fields. Magnetic fields are in the core of planets and in suns because you have a lot of moving, hot material.Moving, charged particles are deflected by magnetic fields. Once you have an existing magnetic field, a charged particle that enters into that field is deflected.Earth's magnetic field, approximated, looks like a cored apple. A magnet within the field will align itself with force lines. That's how compasses work.Venus has remanent magnetization. Imagine you have melted material, magma. In that magma, different rocks and minerals will crystallize at different temperatures.These magnetic fields are life-sustaining. There's plenty of healthy= risks i space. Magnetic fied reject charged materials, so when the sun spits charged materials at us, they can't get that far.Temperature of space:27 kelvins (not degrees kelvin, but kelvins. that's the proper use. so you could write about it as if scientists said kelvins, and non-scientists said degrees kelvin.)That's somewhat misleading--if you're illuminated by the sun, for instance, then that's going to warm you up.It's also misleading due to mass density. Heat is energy transferred between bodies, orbetween a body and its surroundings, as a result of temperature differences only. 1) Conduction, like sitting in a bath, or touching a stove. 2) Convection occurs when and only when you have a fluid heated from below; fluid, to a scientist, is a state of matter that will flow, a liquid, plasma, gas, or sometimes a rock. 3) Radiation, when it comes to heat in a star environment, radiation is pretty much it. That's electromagnetic radiation, not particle radiation.What if you, as a human, was exposed to space? Would you freeze?Yes, eventually you would freeze. It would take several thousand years ... because there's nothing to carry away the heat, since there's so little density in the vacuum. There is no medium to carry away the temperature. There's only radiation to create an equilibrium in temperature, and that's a slow process.So what would happen to you? Would you pop? Not if you didn't hold your breath. The bends are pretty nasty, though. If you don't hold your breath, the air will go out your mouth, and out your nose, taking the path of least resistance, instead of going through your chest. The air in your blood though will bleed out, bursting blood vessels in eye, ear, nose, skin. Also, when you inhale, your body absorbs oxygen, but also nitrogen. When you undergo sudden depressurization, nitrogen bubbles into your bloodstream, causing "the bends"--or decompression sickness--which has a lot of symptoms, and particularly makes the joints very painful.So in space, you would survive... you'd have about 20 seconds of useful consciousness before your brain faded. You could probably survive about 2 minutes of exposure, if you were rescued by someone else.Jane Espenson, intro to the science of battlestar gallactica--"When I needed to describe the effects of death in a vacuum, I needed to resist rumor ("Your lungs pop out of your nose!") and find out what really happens. (Your lungs don't pop out your nose or anywhere else interesting.)'"Single event upsets--when a charged particle like solar wind, a cosmic ray, which can hit a bit in your compute rand change the value from zero to one, which could cause you to "jump" in a science fiction show to a place that was completely unintended. People wondered if this could really happen when Kevin recommended it as a plot point to BSG, but a few days later, a real event happened that proved it could.Monte Cook asks Say you've got an oxygen tank and a mask and you're blown into space. How does that change things? Kevin says, pain--you'd have a spreading, creeping pain as your blood vessels break, and the alveoli in your lungs break, and the fluid in your ear canals start to boil and eeeeep.Sex in space--conception, birth, etc. Kevin says they've done experiments with animals breeding in space. Zero g turns out to be bad for fetal development. He doesn't know details, but rodents that conceive in space give birth to deformed progeny.NASA's not about science, says Kevin. It's about engineering. Putting stuff into space. Building, designing, operating stuff. There are science people in academia that work with NASA, but he's a rare scientist who does.Bud Sparhawk, I've written a bunch of Sam Boone stories that center on intestinal gas. Humans have about 4.5 meters of intestinal gas. You're a balloon. What happens when you expose that to space? Kevin says, via colorful anecdote, that the air gets expelled.Van Allen belts between us and the moon. You pass through them so quickly that it just doesn't matter, even though it's high radiation. People argue about how to shield spacecraft from radiation, and there are discussions about shielding craft from radiation. Kevin says that he thinks the same factors that make space vessels prone to radiation could affect small planets; if you colonize a small planet, it might not be able to generate enough of a protective radiation shielding.There are issues in getting into and getting out of space that have to do with accelerations, and the human tolerance for acceleration, says Mike. Kevin says you can handle about 9Gs. Mike says one of the books (listed below) has tables about what you can survive, when you pass out, and so on.Kevin says 9G is G-lock, and you can see it coming, and you know, no ifs ands or buts, you will pass out. The only thing you can do is put your plane in such a position that when you wake up, you'll be okay. You wear high-G pants, when you plane makes a high G maneuver, the pants squeeze the air, trying to force the air back into your head. Your tolerance will vary based on the orientation of the plane. If you're in positive G, you can do 9, if you're in negative, you can't. How long do you pass out? Kevin says 20 seconds or so, which is a long time at those speeds. If you pass out, you can think about you're about to pass out, then you go grey (your visuals doing poorly), then you go black. If you are traveling negative G when you pass out, you go red instead.Air Combat USA in Los Angelos will train you how to dogfight, a bit, for about $1000. Kevin says he did it and flew to 5G.Mike recommends books that he uses as references for topics that come up over and over in science fiction, like what happens when you're exposed to vacuum:Sex in Space by Laura S. WoodmanseeTeaching Science Fact with Science Fiction written and illustrated by Gary RahamSpacefaring: The Human Dimension by Albert A. HarrisonThe Giant Leap: Mankind Heads For the Stars by Adrian BerryDo Your Ears Pop in Space? by R. Mike Mullane