A kid-sized space rock went BOOM over New England

Professor Pip galloped up the hilltop with his green lab coat flapping behind him, brass telescope tucked under one arm and a bright red balloon bobbing in the other paw.

"There!" he pointed. A long, smoky white streak still curled high above the meadow. "Did you see it, did you see it?!"

"It looked like a comet!" gasped Mia.

"And then it went BOOM!" said Leo, hands clapped over his ears even though the boom was long gone.

Pip's tail twitched with delight. "That, my brilliant friends, was a meteor. A chunk of rock from far out in space, about the size of you, Leo, came whizzing into Earth's air at forty-two thousand miles per hour."

Leo blinked. "Faster than a jet?"

"Faster than fifty jets stacked end to end and lit on fire," Pip said, "and far above us — about thirty-one miles up — it heated up so much that it shattered."

He held up the balloon. "But the BOOM you heard isn't from breaking. It's from going faster than sound. Watch."

He blew the balloon bigger and bigger and bigger. Mia covered her ears. Leo squeezed his eyes shut. POP!

The children jumped, then giggled.

"That tiny pop," said Pip, holding up the rubbery remains, "was the air around the balloon getting squished so fast it slammed back into itself. When a meteor — or a jet — punches through the sky faster than sound can move, it squishes a giant wall of air just like that. We call that a sonic boom."

"Oh!" Mia's eyes went huge. "Like when I jump into the pool and a big wave smacks the side?"

"Exactly right!" Pip clapped his paws. "Only made of air instead of water."

Pip lifted his brass telescope and gazed at the lingering smoke trail. "Somewhere down on a Cape Cod beach right now, there might be a little black pebble lying in the sand. Older than dinosaurs. Older than Earth itself. Just sitting there."

"Now," he said, handing the kids each a fresh balloon, "blow these up. Run downhill. Let them go. Tell me which way they push you — and where the air goes after."