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1 .This is Scientific American 60-Second Science. I'm Christopher Intagliata.
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2 .Aside from all the satellites, and the space station orbiting the Earth, there's a lot of trash circling the planet too.
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3 .Twenty-one thousand baseball-sized chunks of debris, according to NASA.
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4 .But that number's dwarfed by the number of small particles.
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5 .There's hundreds of millions of those.
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6 ."And those smaller particles tend to be going fast.
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7 .So you think of picking up a grain of sand at the beach, and that would be on the large side.
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8 .But they're going 60 kilometers per second."
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9 .Sigrid Close, an applied physicist and astronautical engineer at Stanford University.
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10 .Close says that whereas mechanical damage-like punctures-is the worry with the bigger chunks, the dust-sized stuff might leave more insidious, invisible marks on satellites-by causing electrical damage.
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11 ."We also think this phenomenon can be attributed to some of the failures and anomalies we see on orbit, that right now are basically tagged as 'unknown cause.'"
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12 .Close and her colleague Alex Fletcher modeled this phenomenon mathematically, based on plasma physics behavior.
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13 .And here's what they think happens.
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14 .First, the dust slams into the spacecraft. Incredibly fast.
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15 .It vaporizes and ionizes a bit of the ship-and itself.
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16 .Which generates a cloud of ions and electrons, traveling at different speeds.
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17 .And then: "It's like a spring action, the electrons are pulled back to the ions, ions are being pushed ahead a little bit.
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18 .And then the electrons overshoot the ions, so they oscillate, and then they go back out again."
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19 .That movement of electrons creates a pulse of electromagnetic radiation, which Close says could be the culprit for some of that electrical damage to satellites.
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20 .The study is in the journal Physics of Plasmas.
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21 .The implications of these small particles on future spaceflight is huge.
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22 ."One of my dreams is interstellar travel.
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23 .So I love Star Trek, I grew up hoping I could build something to get outside our solar system, and I feel like this is just one of the many things we have to worry about.
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24 .I think the space environment as a whole is still something we need to tackle."
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25 .Before it tackles any astronauts a long way from home.
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26 .Thanks for listening, for Scientific American 60-Second Science. I'm Christopher Intagliata.
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