Innholdsfortegnelse for May/June 2020 i Ask Science and Arts Magazine for Kids and Children

A GIANT’S HEART An adult human’s heart beats 60 to 100 times a minute, on average. But a hamster’s heart can beat 400 times a minute. Smaller animals usually have faster heartbeats than bigger animals. So what about the biggest animal on Earth—the blue whale? Researchers decided to find out with the help of some stick-on microphones. The team used a long pole to stick tiny sensors onto whales when they came up for air at the ocean’s surface. Suction cups held the sensors tight to each animal’s skin. The sensors could pick up the sound of the whale’s heartbeat. The sensors showed that a blue whale’s heart beats almost 40 times a minute at the surface. But when the whale dived deep, its heartbeat slowed down to just twice…

Beyond Earth, past Jupiter and Saturn, and farther than Pluto lies a cold and distant region called the Oort Cloud. Out here, trillions of dirty, icy lumps surround the solar system like a vast, loose bubble. Scientists believe that these lumps were left over when the planets formed about 4.5 billion years ago. Now and then, a lump gets pulled out of its peaceful orbit by the gravity of a star or planet. It plunges into the inner solar system on a wild ride toward the sun. A comet is born. A Comet’s Journey Most pictures of comets show a bright ball of light with a long, glowing tail. That’s how comets look when they pass Earth. But they don’t start out that way. Our baby comet leaves the Oort…

Asteroids All Around Asteroids are space rocks, left over from when the solar system formed 4.5 billion years ago. They are some of the oldest objects in the solar system, so they are very interesting to scientists. Asteroids can be a few feet (1 m) to hundreds of miles (500 km) across. They spin and travel around the sun in orbits, just like planets do. Most are found in the asteroid belt, between the orbits of Mars and Jupiter. Asteroids are too small for their insides to heat up and melt. So the rocks in asteroids haven’t changed much since the start of the solar system. Asteroids are like little rock museums floating in space. Scientists can look at them to see what the solar system was like long ago.…

Where do space rocks come from? Most are left over from when the solar system was born, 4.5 billion years ago. The sun and planets formed from a big spinning cloud of gas and space dust. And there are still bits of leftover rock (and gas) floating around. ASTEROID An asteroid is any small rocky object that orbits the sun. Asteroids range in size from a few feet to many miles across. They are smaller than planets or moons. Many have odd shapes. Some are solid rock or metal. Others are loose clumps of pebbles, dust, and ice, gathered together like a leaf pile. Sometimes asteroids run into each other and split up or stick together. There are millions of asteroids in our solar system, left over from when the…

Oumuamua On the night of October 19, 2017, the Pan-STARRS telescope in Hawaii got to work, scanning the skies for asteroids. But that night, it found something new. It spotted a small object moving fast—five times faster than a normal comet. It was zooming away from the sun on a wide, curving path. Over the next several days, telescopes around the world tracked the object. They noticed that it got brighter and darker about every seven hours. What could cause that? Maybe the object had a long shape that was tumbling over and over. When they traced the path to see where it had come from, it pointed outside our solar system entirely. The object was a visitor from another star! It was the first extrasolar space rock every spotted.…

What are the chances? Small rocks and dust from space rain down on Earth all the time—several hundred tons fall every year. Most burn up in the atmosphere or leave pebble-sized meteorites. The space rock that wiped out the dinosaurs was huge, about 6 miles wide. Luckily, asteroids this big are rare. And space is vast. The chances of a big wandering rock crossing Earth’s path exactly when Earth is in the way are extremely small. All in all, astronomers estimate that the chance of a city-sized asteroid hitting Earth is about once in 100 million years. (That doesn’t mean one WILL hit Earth every 100 million years—that’s just the average chance.) So, probably not something to worry about a lot. But still, it could happen, right? It could. Though…

Tight Fit Can you fit a quarter through a dime-sized hole? Trace around a dime on an index card or stiff paper. Then carefully cut out the circle to leave a hole the size of the dime. Can you get a quarter through this hole without tearing the paper? That seems impossible. A quarter is larger than a dime. Try this. Fold the paper so that the fold goes across the middle of the hole. With the fold pointing down, place the quarter so that it sits in the hole. Of course, the quarter just sticks out below the paper and doesn’t fall through. But if you use your fingers to gently pull the sides of the paper apart and up, the hole stretches and the quarter falls through. The…

How can you tell if a rock is a meteorite or just a rock? Here are a few signs to look for. Is it a bit heavy? Meteorites are often a bit heavier than ordinary rocks. Many contain metal. But there are also heavy Earth rocks. Does it look burnt? Falling meteorites heat up super hot. Most vaporize entirely. Bits that survive the trip usually have a burnt crust that is darker than the rock inside. Often the crusts have melty crackle lines and flake off easily. No holes Meteorites do not have holes or air pockets in the rock. This can be an easy way to tell them apart from lava and slag, a human-made rock left over from metal-making. Does its surface have smoothed dents? Often, meteorites have…

One night, when I was a little girl, my father took me outside to show me the stars. As he pointed out the constellations, we spotted a visitor to our sky. A comet! I gazed at the glittering sky with wonder. That was one of the first comets I ever saw, but it wasn’t the last. My name is Caroline Herschel, and I’m a comet hunter. Music of the Stars I was born in Hanover, Germany in 1750. When I was 22, I moved to England to live with my older brother, William. He was a musician. At the time, I wanted to be a singer. William thought I had a pretty voice. He offered to give me singing lessons in return for doing his housekeeping. I practiced and practiced…

In our January issue we asked you to design a special house just for pigeons. Thanks to all you amazing avian architects for showing us your shelters! Send your letters to Ask Mail, 70 East Lake St., Suite 800, Chicago, IL 60601, or have your parent/guardian email us at ask@cricketmedia.com. Dear Marvin, I have a funny prank for you: get Bot to zap a rock with his laser, so that Plush notices it. She’ll think it’s a meteorite. She can cool it down with a fan and add it to her specimen box. She could then draw a hippo on it. Zachary M. Dear Zachary, See, I keep telling her. It’s not me, it’s the universe throwing rocks! It would be so cool to find a meteorite. But you’re right,…