Attack from Outer Space

    At that moment, the people of Chelyabinsk look up. They’re puzzled. A huge fireball streaks across the blue-pink morning sky. Then it disappears. A trail of smoke is left behind. Some people run outdoors for a better look. Others pull their cars over to gaze at the sky.

    What was that? Was it a plane crash? 

    Was it aliens? 

    Two long minutes pass, and then . . . 

    BOOM! SMASH!

    The full force of the explosion finally reaches Earth. It feels like a bomb. Walls fall down. People are knocked to the ground. Windows shatter. In an instant, 1,600 people are injured. 

    They are lucky. It could have been worse. 

    The people of Chelyabinsk look up. They’re puzzled. A huge fireball streaks across the sky. Then it’s gone. It leaves a trail of smoke. Some people run outdoors for a better look. Others pull their cars over to gaze at the sky.

    What was that? Was it a plane crash?

    Was it aliens?

    Two minutes go by. Then . . .

    BOOM! SMASH!

    The full force of the explosion reaches Earth. It feels like a bomb. Walls fall down. People are knocked to the ground. Windows shatter. In an instant, 1,600 people are injured.

    They’re lucky. It could have been worse. 

    At that moment, the people of Chelyabinsk look up in surprise and confusion. A massive fireball streaks across the blue-pink morning sky. Then it vanishes, leaving behind a trail of smoke. Some people hurry outdoors for a better look. Others pull their cars over to gaze at the sky.

    What was that? Was it a plane crash?

    Was it aliens?

    Two long minutes pass, and then . . .

    BOOM! SMASH!

    The full force of the explosion finally reaches Earth. It feels like a bomb. Walls fall down, people are knocked to the ground, and windows shatter. In an instant, 1,600 people are injured.

    They’re lucky—it could have been considerably worse. 

    Do you ever look up and see a shooting star? It’s beautiful, but don’t let the name confuse you. A shooting star is not really a star. It’s a meteor. A meteor is a space rock burning up in Earth’s atmosphere. As it burns, it creates a stream of light.

    Our solar system has millions of rocks. There are large space rocks called asteroids. There are smaller space rocks called meteoroids. There are comets, which are part dust and part ice. 

    Very large, very bright meteors—like the one in Chelyabinsk—are called fireballs. Any meteors that make it to Earth’s surface are called meteorites. (To better understand these differences, look at the infographic below.)

    Have you ever seen a shooting star? Don’t let the name fool you. A shooting star isn’t really a star. It’s a meteor. A meteor is a space rock burning up in Earth’s atmosphere. As it burns, it creates a stream of light.

    Our solar system has millions of rocks. There are large space rocks called asteroids. There are smaller ones called meteoroids. There are comets, which are part dust and part ice.

    Very large, very bright meteors—like the one in Chelyabinsk—are called fireballs. Any meteors that reach Earth’s surface are called meteorites. (To better understand these differences, look at the infographic below.)

    Have you ever looked up and seen a shooting star? It’s beautiful, but the name can be misleading. A shooting star isn’t really a star. It’s actually a meteor—a space rock burning up in Earth’s atmosphere. As it burns, it creates a stream of light.

    Our solar system contains millions of rocks. There are large space rocks called asteroids, and there are smaller space rocks called meteoroids. There are comets, which are part dust and part ice.

    Very large, very bright meteors—like the one in Chelyabinsk—are called fireballs. Any meteors that make it to Earth’s surface are called meteorites. (For a better understanding of these differences, look at the infographic below.)

    Space rocks are leftovers from when the planets of our solar system formed about 4.5 billion years ago. The rocks move around the sun in circles called orbits. Sometimes they knock into each other, bouncing around like bumper cars. 

    Each day, tons of debris from these rocks travels toward Earth. Most of it burns up in the atmosphere without causing any harm. But if an asteroid larger than a mile across were to hit Earth, it would be a disaster. 

    How do we know?

    Sixty-six million years ago, a large meteor crashed into Earth off the coast of what is now Mexico. It was about 6 miles wide. Scientists believe dust clouds from the explosion blocked the sun’s light and warmth. 

    This caused plants and animals to die all over the world. It’s also likely why dinosaurs became extinct. Could it happen again?

    Space rocks are left over from when the planets of our solar system formed billions of years ago. The rocks move around the sun in circles called orbits. Sometimes they bump into each other and bounce around.

    Every day, tons of debris from these rocks travels toward Earth. Most of it burns up in the atmosphere and does no harm. But if an asteroid larger than a mile across were to hit Earth, it would be a disaster.

    How do we know?

    Sixty-six million years ago, a meteor hit Earth near what is now Mexico. It was about 6 miles wide. Experts say dust clouds from the explosion blocked the sun’s light and warmth.

    This caused plants and animals to die all over the world. It’s probably why dinosaurs became extinct. Could it happen again?

    Space rocks are leftovers from when the planets of our solar system formed approximately 4.5 billion years ago. The rocks move around the sun in circles called orbits. Sometimes they knock into each other, bouncing around like bumper cars.

    Each day, tons of debris from these rocks travels toward Earth. Most of it burns up in the atmosphere without causing any harm—but if an asteroid larger than a mile across were to hit Earth, it would be a disaster.

    How do we know?

    Sixty-six million years ago, a large meteor—roughly 6 miles wide—crashed into Earth off the coast of what is now Mexico. Scientists believe dust clouds from the explosion blocked the sun’s light and warmth.

    This caused plants and animals to die all over the world, and it’s probably the reason dinosaurs became extinct. Could it happen again?

    Before Chelyabinsk, the last time a meteor caused serious damage was in 1908. Strangely, it was also in Russia. A man named S.B. Semenov was sitting on his porch. Suddenly, the sky lit up, and he was knocked to the ground. Later he said the heat “almost burned the shirt off me.” 

    Semenov was more than 40 miles away from Tunguska, where the space rock hit. Still, he felt its power. 

    The Tunguska meteor was much bigger than the one in Chelyabinsk. It was much closer to the ground too. The blast knocked down 80 million trees in a space that was more than twice the size of New York City. (Luckily, no one lived in this vast area of Russian wilderness.)

    Before Chelyabinsk, the last time a meteor caused serious damage was in 1908. It was in Russia too. A man named S.B. Semenov was sitting on his porch. Suddenly, the sky lit up. He was knocked to the ground. Later he said the heat “almost burned the shirt off me.”

    Semenov was more than 40 miles away from Tunguska, where the space rock hit. Still, he felt its power.

    The Tunguska meteor was bigger than the one in Chelyabinsk. It was closer to the ground too. The blast knocked down 80 million trees in a space more than twice the size of New York City. (Luckily, no one lived in this vast area of wilderness.)

    Before Chelyabinsk, the last time a meteor caused serious destruction was in 1908. Interestingly, it was also in Russia. As a man named S.B. Semenov was sitting on his porch, the sky suddenly lit up, and he was knocked to the ground. Later he reported that the heat “almost burned the shirt off me.”

    Although Semenov was more than 40 miles away from Tunguska, where the space rock hit, he still felt its extraordinary power.

    The Tunguska meteor was much larger, and also much closer to the ground, than the one in Chelyabinsk. The blast knocked down 80 million trees in a space more than twice the size of New York City. (Fortunately, no one lived in this vast area of Russian wilderness.)

Outer Space

1- A meteoroid is a smaller space rock that orbits the sun. It’s usually a piece of an asteroid that has broken off. 

2- An asteroid is a large space rock that orbits the sun.

Earth’s Atmosphere

3- A comet also orbits the sun. But it’s not actually a rock—it’s made of dust and ice.

4- A meteor is  a space rock that burns up as it enters Earth’s atmosphere. It creates a stream of light.

Earth

5- A meteorite is a space rock that has made it to Earth’s surface. 

Outer Space

1- A meteoroid is a smaller space rock that orbits the sun. It’s usually a piece of an asteroid that has broken off. 

2- An asteroid is a large space rock that orbits the sun.

Earth’s Atmosphere

3- A comet also orbits the sun. But it’s not actually a rock—it’s made of dust and ice.

4- A meteor is  a space rock that burns up as it enters Earth’s atmosphere. It creates a stream of light.

Earth

5- A meteorite is a space rock that has made it to Earth’s surface. 

Outer Space

1- A meteoroid is a smaller space rock that orbits the sun. It’s usually a piece of an asteroid that has broken off. 

2- An asteroid is a large space rock that orbits the sun.

Earth’s Atmosphere

3- A comet also orbits the sun. But it’s not actually a rock—it’s made of dust and ice.

4- A meteor is  a space rock that burns up as it enters Earth’s atmosphere. It creates a stream of light.

Earth

5- A meteorite is a space rock that has made it to Earth’s surface.