As Byeol-maru orbited Mars, Hyeongseop spotted a small, lumpy rock shaped like a potato zipping past the window. It was circling Mars so quickly that it nearly vanished from sight in an instant.
“Byeoli, what was that? It looked like a totally lumpy chunk of rock.”
“That’s Phobos, one of Mars’s two moons. Mars has two of them, Phobos and Deimos.”
“Why isn’t it round like a normal moon? It looked so bumpy.”
“Larger moons usually pull themselves into a round shape under their own weight, but Phobos and Deimos are too small and light for that to happen. So they’ve kept the same lumpy, asteroid-like shape they probably always had.”
Hyeongseop steered Byeol-maru a little closer to get a better look at Phobos. Its surface was covered in craters big and small.
“Were these moons always next to Mars?”
“That’s still not entirely certain. Scientists have two main ideas. One is that they were originally asteroids drifting nearby that got captured by Mars’s gravity. The other is that long ago, something huge crashed into Mars, and the debris that flew off clumped together to form these two moons.”
“You said Phobos is closer, right? So what happens to it?”
“Phobos is so close to Mars that its gravity is slowly pulling it inward. Far in the future, it might crash into Mars, or break apart into a beautiful ring circling the planet.”
“Is Deimos as big as Phobos?”
“No, Deimos is much smaller than Phobos. Seen from the surface of Mars, Phobos would look much smaller than our Moon looks from Earth, and Deimos would look even tinier, almost like a bright star. If anyone ever lived on Mars, they’d see one chunky potato and one tiny sparkle sharing the night sky.”
“Whoa. So what about Deimos, then?”
“Deimos sits farther away, so instead it’s very slowly drifting even farther from Mars. The two moons are heading toward two completely different fates.”
“Could people actually go visit them someday?”
“Scientists are actually planning a mission to send a spacecraft to Phobos someday, to collect soil and rock samples. Phobos has such weak gravity, less than a thousandth of Earth’s, that a person standing on it could practically float away with just a little hop. By the time you’re grown up, you might get to hold that soil in your own hands.”
As Byeol-maru drifted slowly between the two moons, Hyeongseop imagined the very distant futures waiting for these small, lumpy rocks. One destined to break apart, the other destined to drift away, each quietly circling Mars toward a completely different ending, and somehow that made him feel a little wistful for them both.
“Mars’s two moons are too small to pull themselves round, and they’re drifting toward two very different fates, one crashing inward, one drifting away.”
Your Turn Now
Share with someone today what you remember.
- Why are Phobos and Deimos so lumpy?
- What will happen to Phobos?
- What will happen to Deimos?
(Check when ready: 1. They’re too small to pull themselves round. 2. It’s being pulled toward Mars and may crash or break apart. 3. It’s slowly drifting farther from Mars.)
답글 남기기