Tycho’s Supernova

Tycho Brahe was one of the greatest observers of the night sky. In the era before telescopes, he compiled some of the most accurate star catalogs in history. It didn’t take a lot of talent for him to notice a bright new star in Cassiopeia, though. Tycho logged it 450 years ago tonight. He studied the star extensively, so today it’s known as Tycho’s Supernova.

At the time, the heavens were considered not only unchanging, but unchangeable. A new star suddenly flaring to life didn’t fit that model at all. It helped create a revolution in our understanding of the universe.

It took centuries for astronomers to figure out what had created the new star: a supernova. A “dead” star known as a white dwarf had pulled gas off the surface of a companion star. Eventually, so much gas piled up on the white dwarf that it caused a runaway nuclear explosion. That blasted the white dwarf to cosmic dust.

The supernova was extremely bright. It eventually got as bright as Venus, the brightest object in the night sky after the Moon. And it remained visible for a year and a half.

Today, the debris from that explosion forms a bubble of gas and dust. It’s expanding at two or three percent of the speed of light.

The bubble is too faint to see without a telescope. But you can easily spot its location. It’s close to the left of the center point of the “W” that outlines Cassiopeia, high in the northeast at nightfall.

Script by Damond Benningfield