Hubble observed a supernova brighter than its galaxy

A supernova releases as much energy in days as our Sun does in several billion years. In 2018, the Hubble Space Telescope observed a supernova 70 million light years away, which outshone its entire galaxy until it faded away over the following year.

This video zooms into the barred spiral galaxy NGC 2525, located 70 million light-years away in the southern constellation Puppis. As we approach an outer spiral arm a Hubble time-lapse video is inserted that shows the fading light of supernova 2018gv. Hubble didn’t record the initial blast in January 2018, but for nearly one year took consecutive photos, from 2018 to 2019, that have been assembled into a time-lapse sequence. At its peak, the exploding star was as bright as 5 billion Suns.

While nuclear fusion and a slow neutron capture process form all the elements up to 83 (Bismuth), the elements are also produced very rapidly in supernovae along with all the heavier elements. Supernovae have produced the the bulk of the universe’s precious metals, silver, platinum and gold, and are responsible for the creation of the heaviest elements up to uranium.

Supernovae like this all peak at the same brightness and so can be used to accurately measure the distance of their host galaxy, allowing accurate measurement of the universe’s expansion rate. The current best estimate is that the universe is expanding at a rate of 69.3 km/sec/Megaparsec plus or minus 0.8. That means that for every Megaparsec (about 3 million light years) that you go out, the Universe is expanding 69.3 km/sec faster. So that means that NGC 2525 is moving away from us at a speed of around 1500 km/s or half a light year each century.