The remnant of supernova 1987a, located in the Large Magellanic Cloud some 165,000 light years away. Image credit: Noel Carboni & the ESA/ESO/NASA Photoshop FITS Liberator.

Supernovae glow for decades thanks to radioactivity

The flash lasts seconds, the brightness dies down in months. Yet centuries later, the remnant still shines.

“When we recall the past, we usually find that it is the simplest things — not the great occasions — that in retrospect give off the greatest glow of happiness.” -Bob Hope

In 1987, the closest supernova was observed since humans last saw one with our naked eyes in 1604.

Image credit: NASA/ESA/JHU/R.Sankrit & W.Blair, of an optical/IR/X-ray composite of the 1604 supernova remnant, the last naked-eye supernova to occur within our galaxy.

A rush of neutrinos and a flash of light illuminated the heavens as a stellar core imploded, blowing off the massive star’s outer layers.

This image shows the remnant of Supernova 1987A seen in light of very different wavelengths. ALMA data (in red) shows newly formed dust in the centre of the remnant. Hubble (in green) and Chandra (in blue) data show the expanding shock wave. Image credit: ALMA (ESO/NAOJ/NRAO)/A. Angelich. Visible light image: the NASA/ESA Hubble Space Telescope. X-Ray image: The NASA Chandra X-Ray Observatory.

While a supernova brightens, reaches a peak and fades away over a few months, SN 1987A has been visible for decades.