How did a rock the size of a golf ball light up the sky over Tennessee?

Hook

Why and how did a rock the size of a golf ball light up the sky over Tennessee? Earlier this month, a fireball streaked from North Carolina into Tennessee, bright enough that people across Tennessee and North Carolina saw it. NASA says it was a piece of an asteroid, about two inches across and weighing roughly six ounces.

Speed

So how does something that small make that much light? Speed. NASA clocked it at about forty seven thousand miles per hour. At that speed, even a pebble carries enormous energy. Energy of motion grows with the square of speed, so going ten times faster means a hundred times more energy.

Air

When it hit the upper atmosphere, it slammed into air faster than the air could get out of the way. The air in front of it was squeezed and heated to thousands of degrees. The rock's surface melted and vaporized, and that superheated gas glowed. The glowing streak is what we call a meteor.

Path

NASA's cameras tracked it for about ten seconds. It first appeared about fifty miles above Robbinsville, North Carolina, and disappeared about twenty five miles above East Ridge, near Chattanooga. By then, it had burned away.

Names

A few words help here. Out in space, the rock is a meteoroid. The streak of light is a meteor. Anything that survives all the way to the ground is a meteorite. Most small ones never make it down.

Taurids

The timing was a coincidence. The Taurid meteor shower was active, and Taurids are known for slow, bright fireballs. But NASA says this one wasn't a Taurid. Its path pointed to a fragment of an asteroid, not debris from a comet.

Network

How do we know all this? NASA runs a network of sky cameras across the country, including here in the Southeast. When two or more cameras catch the same fireball, scientists can triangulate its path, height and speed, then work backward to the orbit it came from. And events like this aren't rare. Small space rocks hit our atmosphere every single day, adding up to dozens of tons.

Close

So a six-ounce rock lit up the Southeast because at forty seven thousand miles per hour, the air in front of it turns into a furnace. ThatsWhyHow.