Outside the tent, Grandpa and Eunseo sat in their camping chairs, looking up at the sky.
“Grandpa, there weren’t any maps a long time ago. So how did people find their way across a pitch-black ocean on a ship?”
“They looked at the stars. See that one over there? That’s called the North Star.”
“What’s so special about it?”
“That star barely moves across the sky at all. All the other stars look like they’re slowly circling around all night, but the North Star just stays fixed in the same spot.”
“Why doesn’t it move?”
“Earth spins on an axis, like a top. If you stretched that axis straight up into the sky, it would point exactly at the North Star. So no matter how much Earth spins, that one star always marks north.”
“So if you find that star, you know which way is north?”
“Exactly. Long before compasses existed, sailors checked their direction every night by finding that star. If the North Star was straight ahead, they were heading north. If it was on their right, they were heading east.”
“What did they do on cloudy nights?”
“They used other tricks too, watching where the sun rose and set, the direction of the wind, even the shape of the waves hitting the ship. The stars were the best compass, but not the only one.”
“How did you learn to find the North Star?”
“My own grandfather taught me. First find the ladle-shaped group of stars called the Big Dipper, then draw a line through the two stars at the front of the ladle, and stretch that line about five times as long. Right at the end of it, you’ll find the North Star.”
Eunseo looked up and started searching for the ladle shape.
“Found it! There’s the ladle!”
“Good. Now follow those two stars.”
Eunseo’s finger slowly traced across the sky, and finally stopped on one star.
“Is that it?”
“That’s the one. Now you know how to find your direction too, no map needed.”
“Right where Earth’s axis points, there’s one star that almost never moves. For thousands of years, that single star has been humanity’s compass.”
Your Turn Now
Tonight, share with someone what you remember.
- Why does the North Star barely move in the sky?
- What could old sailors figure out by looking at the North Star?
- Which constellation helps you find the North Star first?
(Check when ready: 1. It sits right where Earth’s axis points. 2. Which direction was north. 3. The Big Dipper.)
답글 남기기