Attack From Outer Space

As the sun rises on February 15, 2013, the people of Chelyabinsk, Russia, start their mornings as usual, eating breakfast, driving to work, and heading to school. But the 1.1 million residents of this busy city are in for a very unusual day. This morning, a space rock 65 feet across—about as wide as your school gym—is headed directly for Chelyabinsk. And nobody has any idea.

This rock has been circling close to Earth for thousands of years. Finally, this morning, it enters our atmosphere—the layer of gases that surrounds our planet.

Zooming toward Earth’s surface, the rock gets hotter and hotter. The heat is so intense that the rock starts to crumble as it travels 40,000 miles an hour—more than twice as fast as most rockets at liftoff. Now it’s about 15 miles above the ground, and it won’t be long until . . . it explodes!

The residents of Chelyabinsk gawk, puzzled, as a brilliant fireball streaks across the blue-pink morning sky and disappears in a blinding flash of light brighter than the sun. An eerie trail of smoke is left behind. Some people run outside or go to the windows for a better look. Others pull their cars over, alarmed.

What was that? A missile? A plane crash? Aliens?!

Two uneasy minutes pass. And then—

BOOM! SMASH!

Thunderous bangs echo as invisible shock waves shake Chelyabinsk. Walls collapse. People are knocked to the ground. Windows shatter, flinging razor-sharp shards of glass into homes, schools, and offices throughout the city. In a single instant, about 1,500 people are injured.

They are lucky. It could have been worse.

As the sun rises on February 15, 2013, the people of Chelyabinsk, Russia are starting their mornings. But the 1.1 million residents of this city are in for an unusual day. A space rock is headed straight for Chelyabinsk. It’s 65 feet across - about as wide as your school gym. And nobody has any idea.

This rock has been circling close to Earth for thousands of years. This morning it enters our atmosphere (the layer of gases that surround Earth).

The rock gets hotter and hotter as it zooms toward Earth. It becomes so hot that it starts to crumble. It travels 40,000 miles an hour. Now it’s about 15 miles above the ground. It won’t be long until . . . it explodes!

The people of Chelyabinsk look up, puzzled. They see a fireball streak across the sky. They watch it disappear in a flash of light brighter than the sun. A strange trail of smoke is left behind. Some people run outside or to windows for a better look. Others pull their cars over.

What was that? A missile? A plane crash? Aliens?! 

Two minutes pass. Then—

BOOM! SMASH!

Bangs echo when invisible shock waves shake Chelyabinsk. Walls collapse. People are knocked down. Windows break. Pieces of glass fly into homes, schools, and offices. About 1,500 people are hurt.

They are lucky. It could have been worse.

Ever look up at the night sky and see a shooting star? Beautiful, yes? Don’t let the name confuse you, though—a shooting star is not really a star; it’s a meteor, the stream of light produced when a rock burns up in Earth’s atmosphere. Our solar system includes millions of rocks, such as asteroids (large space rocks), comets (part rock and part ice), and meteoroids (smaller space rocks). Especially large and bright meteors, like the one in Chelyabinsk, are called fireballs. Any pieces that land on Earth are called meteorites.

Mentions of sacred rocks from the sky appear in writings from ancient civilizations. The Egyptians called meteorites “metal from the sky” and turned them into special jewelry and short, sharp knives called daggers. The Greeks and Romans saw fallen space rocks as messages from the gods. The ancient Chinese carefully recorded meteor showers.

It wasn’t until 1794, though, that German physicist Ernst Chladni proposed that meteorites come from outer space. But no one took him seriously. The common belief at the time was that rocks that fell from the sky came from Earth, having been first swept up by strong winds. Then, in April 1803, thousands of meteorites fell on the French town of L’Aigle. A physicist named Jean-Baptiste Biot went to investigate. Biot’s research finally convinced scientists that rocks can—and do—fall from space.

Now we know that space rocks are leftovers from when the planets of our solar system formed about 4.5 billion years ago. Like the planets, the rocks move around the sun in circles called orbits. Generally, they stay in the asteroid belt, an area between Mars and Jupiter. But sometimes they knock into each other, bouncing around like bumper cars, and stray close to us. Each day, Earth is bombarded by some 100 tons of space debris, most of which 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 catastrophe.

Sixty-six million years ago, an asteroid likely led to the extinction of the dinosaurs. That asteroid was six miles across. It crashed off the coast of what is now Mexico. Scientists believe dust clouds from the explosion blocked out the sun—perhaps for months—causing plants and animals to die.

Could that happen again?

Do you ever look at the night sky 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 the stream of light created when a rock burns up in Earth’s atmosphere. Our solar system has millions of rocks: asteroids (large space rocks), comets (part rock and part ice), and meteoroids (smaller space rocks). Very large, bright meteors are called fireballs. The space rock in Chelyabinsk was a fireball. Any pieces that land on Earth are called meteorites.

People from long ago wrote about sacred rocks from the sky. The Egyptians called meteorites “metal from the sky.” They turned them into special jewelry and knives. The Greeks and Romans believed that space rocks were messages from the gods. The ancient Chinese recorded meteor showers.

In 1794, a German physicist suggested that meteorites come from outer space. But no one took him seriously. At that time, people believed rocks from the sky came from Earth. They thought the rocks were first swept up by strong winds then dropped back to the ground. Then, in 1803, thousands of meteorites fell on a French town. A physicist named Jean-Baptiste Biot went to see. Biot’s research convinced scientists that rocks do fall from space.

Now we know that space rocks are leftovers from long ago. They’re from about 4.5 billion years ago when the planets of our solar system formed. The rocks move around the sun in circles called orbits, like the planets do. Generally, they stay in the asteroid belt, an area between Mars and Jupiter. But sometimes the rocks knock into each other and bounce around like bumper cars. Then they stray close to Earth. Each day, Earth is hit by 100 tons of space debris. Most of this space debris burns up in the atmosphere without causing any harm.

But if an asteroid larger than a mile across hit Earth, it would be a catastrophe.  

Sixty-six million years ago, an asteroid probably led to the dinosaurs’ extinction. That asteroid was six miles wide. Scientists believe dust clouds from the explosion blocked out the sun. The sun may have been blocked out for months. This caused plants and animals to die.

Could that happen again? 

What happened in Chelyabinsk is a reminder of something that’s easy to forget: We live on a planet that is drifting through space, and we’re not alone. Drifting along with us are objects that may someday pose a threat. But scientists around the world are working feverishly to ensure that such an event never happens again.

And fortunately, no one in Chelyabinsk was killed. Most of the injuries were minor. Many people in the area have a new hobby: hunting for meteorites. Even small fragments of the fireball can be worth thousands of dollars.

If you were to see a meteorite, though, you probably wouldn’t think it was anything special. Most look an awful lot like boring old black rocks.

You’d probably walk right by it. 

What happened in Chelyabinsk is a reminder: We live on a planet that is drifting through space. And we’re not alone. Drifting along with us are objects that may someday be a threat. But scientists around the world are working feverishly to make sure that such an event never happens again.

Luckily, no one in Chelyabinsk was killed. Most injuries were minor. Many people in the area have a new hobby: hunting for meteorites. Even small pieces of the fireball can be worth thousands of dollars.

But if you were to see a meteorite, you probably wouldn’t think it was special. Most look like boring black rocks.

You’d probably walk right by it.

Sooner or later, another space rock like the one that exploded over Chelyabinsk will come hurtling toward Earth. But the world’s top scientists are working to make sure that when it happens, we’ll be ready.

NASA, America’s space research agency, uses powerful telescopes to scan the sky for asteroids, meteoroids, and comets. Along with other space agencies around the world, NASA has already found 95 percent of the very largest asteroids. And scientists are building newer, stronger telescopes that will be able to spot smaller space rocks.

Finding space rocks is the first step to protecting the planet. The next step is figuring out where they’re going. The B612 Foundation, an organization founded by former astronauts, is hoping to help with that. B612 is working to create a high-tech digital map of all the asteroids in our solar system that are close to Earth. The map will track the movements of the asteroids and predict whether they are headed our way.

Sooner or later, a space rock like the one in Chelyabinsk will come hurtling toward Earth. But scientists are working to be ready when it happens.

America’s space agency, NASA, uses telescopes to scan the sky for asteroids, meteoroids, and comets. NASA works with other space agencies around the world. And they have already found 95 percent of the very largest asteroids. Scientists are building stronger telescopes which will be able to see smaller space rocks.

The first step to protecting the planet: finding space rocks. The next step is figuring out where they’re going. The B612 Foundation is an organization that hopes to help with that. B612 is making a digital map of the asteroids that are close to Earth. The map will track their movements. It will also predict whether they are headed our way.