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Math Time
q Catharine Conley helps make sure that crafts like the Mars rover Curiosity don’t spread Earth microbes to another planet.
Planet Protector Catharine Conley keeps Earth and other planets safe from alien invaders
Y ou might think an alien invasion is an unlikely event. But for Catharine Conley, it’s a real possibility that keeps her up at night. As NASA’s Planetary Protection Officer, it’s her job to prevent microscopic organisms called microbes from contaminating Earth—and other planets. Microbes exist everywhere on Earth. There are trillions of them on our planet. (A trillion is 1 million times 1 million!) Microbes might also exist on nearby planets, moons, and space rocks called asteroids. As humans travel in space, we run the risk of coming in contact with these alien life-forms. “Imagine if an astronaut got sick on Mars from a microbe we’ve never encountered before,” Conley says. “[If the
microbe came to Earth,] we likely would have no way to stop the new illness from spreading around our planet.” But the concern goes both ways. Scientists don’t want to risk introducing Earth microbes to places in space where they could survive. Earth microbes could harm any alien life on another planet, moon, or space object. In the 1970s, NASA sent two landers to explore Mars as part of the Viking program. Before launch, scientists baked the landers in a giant oven. They were trying to kill all the microorganisms on the crafts. But it’s impossible to get rid of them all. “Wherever humans go, [even if it’s only our spacecraft,] microbes go too,” Conley says. Since the Viking program, Mars-bound spacecraft have
been cleaned but not baked to protect their sensitive instruments. Modern rovers and landers stick to exploring areas on the Red Planet not hospitable for Earth life. This means keeping the craft away from places on Mars where Earth microbes might grow— such as areas with liquid water, Conley says. Could life really survive in the harsh environment of a journey through space? It’s possible! We know that some Earth microbes have survived on the outside of the International Space Station and orbiting satellites. For Conley, her mission is clear. No matter where humans go in the solar system, “we’ll want to make sure we’re not accidentally bringing Earth life along for the ride!” —Stephanie Warren Drimmer
DYN_110116_p12-13_Mars.indd 12 Teacher: Use these questions to spark a conversation after reading. 1. Why is it important not to bring Earth microbes into space? 2. What does the author mean by the term “alien invasion”? 3. If it was possible for humans to go to Mars, would you want to go? Why or why not? Purpose: To read a text that prepares students to use arrays to divide and solve problems with remainders 28 Session 13 9/14/16 3:04 PM
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