The Sound Before the Light

The crackling wouldn't stop.

Maya pulled one headphone off and looked at Soren, who was frowning at the waveform on the laptop screen. They were supposed to be cataloging reef sounds for Dr. Reyes's acoustic monitoring project. Snapping shrimp, parrotfish scraping coral, the low hum of boat motors. Simple stuff. Label the sounds, log the timestamps, help build the database.

But the crackling was everywhere. It sounded like someone frying bacon underwater. Like a thousand tiny campfires.

"It's all shrimp," Soren said. He scrolled through three minutes of recording. The waveform was dense with spikes, packed so tight they overlapped. "There's supposed to be other stuff in here. I can barely find it."

Maya put the headphone back on. She closed her eyes. In between the snaps, she could hear the parrotfish, faintly, like someone chewing gravel in another room. But the shrimp dominated everything.

"How big are they?" she asked.

"Like, five centimeters. Maybe."

"That's the size of my thumb."

"Yeah."

She listened again. One snap in particular was louder than the others, so sharp it distorted the recording slightly. She pointed at its spike on the screen. "That one. Play just that one."

Soren isolated it. Slowed it down.

At normal speed it was a single crack. Slowed to one-tenth speed, it became something else entirely. There was the snap itself, then a fraction of a second later, a second pulse. A kind of thud.

"Two sounds," Maya said.

"I see it." Soren leaned closer. Two peaks, very close together. "The second one's quieter but it's definitely separate."

"So what's making the second sound?"

Soren pulled up the species file Dr. Reyes had given them. Alpheus heterochaelis. Pistol shrimp. He read for a minute, then read for another minute, and Maya watched his face change.

"Okay," he said slowly. "So the snap isn't actually the sound of the claw closing."

"What is it then?"

"The claw closes so fast that it shoots out a jet of water. And the water jet moves so fast that it creates a bubble. A cavitation bubble. The water pressure drops so quickly in one spot that it basically rips apart, makes a vacuum pocket, and then the water slams back together and the bubble collapses." He looked up from the screen. "And when the bubble collapses, the temperature inside it reaches four thousand seven hundred degrees Celsius."

Maya took off both headphones. "How hot is the surface of the sun?"

"I don't know exactly. Hold on." He typed. "Five thousand five hundred, roughly."

They both looked at the little aquarium tank across the room. Dr. Reyes kept a live pistol shrimp in there, a pale greenish thing with one comically oversized claw. It was sitting on a rock doing absolutely nothing.

"That thing," Maya said, "is making temperatures close to the surface of the sun. In a fish tank."

"In a bubble the size of, like, I don't even know. Tiny."

"And the second sound on the recording?"

"That's the bubble collapsing. The first sound is the water jet. The second is the implosion."

Maya walked over to the tank. The shrimp didn't move. Its big claw was half-open, resting. Pale, translucent, the size of a nickel.

"There's something else," Soren said from behind her. His voice had gone quiet in the way it did when something was actually getting to him. "When the bubble collapses, it produces light."

"Light?"

"A flash of light. From the heat. They call it sonoluminescence. It lasts less than ten billionths of a second and you can't see it with your eyes, but it's there. The shrimp makes a tiny star in the water and it blinks out before anything can even register it."

Maya pressed her forehead against the glass. The shrimp shifted slightly on its rock.

Dr. Reyes came in through the screen door, carrying a cooler and talking on her phone. She held up one finger to them, the universal sign for one minute, then disappeared into the back room still talking about grant deadlines.

Maya turned to Soren. "So every single one of those snaps on the recording."

"Every one."

"Every one of those was a bubble collapsing at almost the temperature of the sun. And making a flash of light that nobody sees."

"Thousands of them. Per minute. On one reef."

Maya sat down on the floor, which she did sometimes when she needed to think at a different altitude. The reef they were recording from was maybe two hundred meters long. There were reefs all over the Florida Keys. All over the Caribbean. All over every warm ocean on Earth.

"Soren. How many pistol shrimp are there?"

"I have no idea. Hundreds of species. They're one of the loudest animals in the ocean. They mess up sonar. During World War Two, submarines used colonies of snapping shrimp to hide from acoustic detection because the noise was so dense it covered everything."

"Submarines hid behind shrimp."

"Behind the sound of shrimp making tiny suns, technically."

Maya laughed, not because it was funny but because her brain needed to do something with what she was feeling. Across every ocean, right now, at this exact second, millions of bubbles were collapsing. Each one a pinprick of star-temperature heat. Each one a flash of light too fast to witness.

The shrimp in the tank snapped.

It was loud, even through the glass. A single hard crack. Maya flinched. Soren flinched. A tiny goby fish on the far side of the tank went rigid and drifted sideways, stunned.

"Did you see a flash?" Maya asked, knowing the answer.

"No. Way too fast."

"But it happened."

"It happened."

They both stared at the tank. The shrimp settled back onto its rock. The goby twitched, recovered, and darted under a shell. The water looked exactly the same as it had five seconds ago, clear and still and holding no evidence at all of what had just occurred inside it.

Maya pressed play on the hydrophone recording. The ocean crackled and snapped and sang with invisible fire, and she turned the volume up.