Science Stories: Strange Supernova, Human Ancestors’ Close Call, and Sunken 16th-Century Ship

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Joe Johnson’s latest Science Stories segment dives into three fascinating discoveries: a never-before-seen supernova, a genetic bottleneck in human ancestors, and a centuries-old shipwreck at the bottom of the sea.

A Supernova Like No Other
Astronomers observed a unique explosion, SN 2021 YFJ, first detected in 2021 and reported in Nature. Unlike typical supernovas, this star had lost almost all of its outer layers, leaving only silicon, sulfur, and argon. When it exploded, it lit up this rare chemical cloud, giving scientists a firsthand look at a star stripped down to its core.

“The explosion lit up material we’ve only theorized about before,” Johnson said. Scientists are still unsure why the star shed its layers — a companion star, a black hole, or some unknown process could be responsible.

Our Ancestors Nearly Didn’t Make It

Around 900,000 years ago, the ancestors of modern humans, Neanderthals, and Denisovans came close to extinction. DNA analysis of over 3,000 people worldwide revealed the breeding population dropped from 100,000 to just 1,300 individuals.

This genetic bottleneck lasted roughly 100,000 years during the Ice Ages. “It’s amazing they survived with so few,” Johnson noted. Without this tiny population, humans as we know them might not exist.

16th-Century Shipwreck Found in French Waters
Deep off Saint-Tropez, French archaeologists discovered a 16th-century trading ship 8,500 feet underwater. While the wooden hull decayed, cargo including 200 ceramic jugs and 100 large platters remains remarkably intact. Many are decorated with Christian symbols and geometric patterns, a vivid glimpse of centuries-old trade.

Johnson called it “a time capsule at the ocean floor,” noting the team will return next year for mapping and possible excavation.

Image: A rare supernova exposes the silicon-rich heart of a massive star, offering astronomers an unprecedented view of stellar death. (Credit: W.M. Keck Observatory/Adam Makarenko)