Science for Kids — August 23: Black hole stars, dolphin schools, and giant Brazilian bones

Professor Pip pushed his crooked spectacles up his nose and lifted a small brass telescope out of his coat pocket. Behind him, the sky was turning the color of a bruised plum.

"Tonight, my fellow scientists," he whispered, tail swishing, "we're hunting something that pretends to be a star."

Mia squinted up. "How can something pretend to be a star?"

"Ah!" said Pip, eyes gleaming. "Watch closely." He rummaged in another pocket and pulled out a flashlight and a bright red silk scarf. "Leo — cover this flashlight with the scarf. Mia — count the tiny lights on the observatory railing."

Leo draped the scarf. The flashlight glowed a warm ruby-red. Mia counted seventeen lanterns.

"Now," said Pip, "come stand five paw-steps behind me and look this way."

The children shuffled back. From where they stood, the wrapped flashlight was just a soft red dot. It looked exactly like a distant star.

"But there's no star inside my paw!" laughed Pip. "There's a bulb and a scarf. From far away, a bright thing glowing through a covering can look like a star — even when it's something else entirely."

He pointed his telescope at the sky. "Astronomers using an enormous telescope in space, called the James Webb Space Telescope, keep finding tiny red dots way out at the edge of the universe. They call them 'little red dots.' They look like stars. But they're much too bright to be one single star."

"So what are they really?" asked Leo.

Pip beamed. "This week, scientists said they think they've figured it out. Inside each red dot is a very hungry black hole — a place where gravity pulls so hard that even light can't escape. As gas swirls in, it heats up and glows red-hot. That glowing cloud is enormous — as wide as our whole solar system — and it wraps around the black hole like Leo's scarf around my flashlight."

"Oh!" Mia gasped. "Like a lantern with a monster inside!"

"Exactly right!" cried Pip, tail swishing so hard his spectacles slipped. "A lantern with a black hole for a bulb. Scientists are calling these 'black hole stars.'"

He looked up at the real stars, quieter now. "Isn't that the loveliest thing? For a long, long time, we thought a bright dot in the sky meant only one thing. But the universe keeps inventing new kinds of dots."

He handed each child a scarf and a small flashlight. "Now you try. Wrap it up — and go be someone else's mystery."

Professor Pip stood on a sunny wooden dock, his tail flicking against the boards. The bay sparkled turquoise. From his enormous coat pocket he produced — well, a very large, empty spiral seashell, about the size of a football.

"My fellow scientists!" he called. Mia and Leo padded over, along with their friend Asha, who was clutching a red plastic fish. "Today we're going to learn about a dolphin who invented a spoon."

"A spoon?" giggled Asha.

"Watch." Pip set the shell on the dock, opening upward. He held out his paw. "Asha, drop your fish."

She dropped it. It bounced across the boards and — plop! — slid neatly inside the shell.

Pip lifted the shell high, tilted it, and the fish tumbled straight down toward his open paw. The children clapped.

"That," Pip announced, spectacles slipping, "is called tool use. When a creature picks up an object and uses it to get a job done, that's a tool. Only a small number of animals in the world do it — some crows, some chimps, some sea otters, and... a very few dolphins in Australia."

Leo's eyes got round. "Dolphins use tools?"

"Precisely!" said Pip. "Off a bay called Hervey Bay, a research drone filmed a mother dolphin named Maserati. She chased a small fish into a giant empty snail shell — bigger than my paw, like this one — then poked her beak in, lifted the whole shell above the water, and shook it until the fish tumbled into her mouth. The scientists call the trick shelling."

"Like a snack cup!" said Mia.

"Exactly right, a snack cup." Pip's tail swished. "But here's the best part. Just minutes after Maserati did it, her calf — her baby, named Bentley — picked up the very same shell and held it the same way. It's the first time scientists have caught a dolphin baby copying a tool trick straight from its mom on camera."

"So she taught him?" asked Leo.

"That's the mystery," said Pip softly. "Scientists used to think dolphins learned this trick from friends, the way you might learn a game from a classmate. This little clip suggests some dolphins might learn it from their mothers, too — like you learning to tie your shoes."

He looked out over the water. Somewhere out there, a real Bentley was probably practicing.

"One drone. One lucky afternoon. One curious calf. And a question we thought was answered gets to be interesting again."

He handed each child a small paper cup and a marble. "Now you try — chase the marble into the cup. Every scientist starts with a spoon."

The dust in the air smelled like hot stone. Professor Pip stood at the edge of a great red pit, brush in one paw and pocket notebook labeled "Notes" in the other. Behind him, poking out of the earth, were rib bones taller than a grown-up.

"Oh my whiskers," he breathed.

Mia, Leo, and their friend Beatrix craned their necks up. And up. And up.

"Professor Pip," Beatrix whispered, "is that a whole dragon?"

"Nearly!" said Pip, tail poofing out with excitement. "It's a sauropod — a plant-eating dinosaur with an enormously long neck and an enormously long tail. This one stretched about twenty meters. That's as long as two school buses parked end to end."

He tapped his little brush against the rock. "But before we get to the size, let's answer the question: how did anyone find this?"

"Someone dug it up?" said Leo.

"Almost. A construction crew was clearing land here in Brazil to build a road when their machines started scraping over strange, curved shapes. They stopped digging, called paleontologists, and — precisely! — under the dirt was this."

He handed each child a soft brush and knelt beside a rib the size of a couch. "Watch closely. Bones this old aren't loose — they're stuck inside rock. To free them, we use tiny brushes and very careful hands. Sweep, don't scrape. That's how we do paleontology."

The children swept. Little clouds of red dust rose off the ancient bone.

"Now — how do we know this creature was so gigantic?" Pip asked.

"You measured?" guessed Mia.

"Even better." Pip pulled out a small measuring tape and stretched it along the exposed backbone. "We measure the bones we have, and then we compare them to sauropod skeletons we already know from other places. If one thighbone is twice as long as a cousin's thighbone, the whole animal was probably about twice as big."

Leo puffed out his chest. "Like how big shoes belong to a big person!"

"Exactly right!" Pip laughed, spectacles bouncing.

He looked up along the impossible neck. "And here's the wonderful bit. This creature walked here — right here — about ninety million years ago, munching leaves twenty meters over your head. Then it lay down. And the earth took it in. And a hundred lifetimes later, a bulldozer bumped into a rib and woke up the whole story."

He handed each child a fresh brush. "Now you try. Sweep very softly. Somewhere in this pit, another bone is waiting to say hello."