About 170 years ago, a star nearly exploded in the Southern constellation Carina. I say nearly for a few reasons. On Earth, observers saw a dim, seemingly-average star become the second brightest star in the night sky. It stayed that way for 20 years before slowly fading.
When we looked at it with telescopes, we found that whatever happened to Eta Carinae, it ejected more than 30 times the mass of our Sun in that short twenty year period, creating what we now call the homunculus nebula.
Eta Carinae is a multiple star system 7500 light years away from Earth, so rest assured any explosion won’t cause us any trouble. This system is massive, with the main star weighing as much as 150 solar masses, and a companion weighing 30 solar masses. The whole system has a combined luminosity of 5 Million suns. This thing is bright, hot, and wild. It may be the most massive stellar system in the known Universe. The only problem is that we can’t get a good look at it to nail down its exact mass.
As far as we know, Eta Carinae’s eruption was a prequel to a Supernova explosion. Don’t get too excited though, this bomb won’t go off for a Million years or so, which is still a relatively short time frame, Astronomically speaking.
Still, it’s amazing to see the above image as the nebula is clearly expanding in two huge lobes of gas, lined with dark filaments of dust. The stars in the centre are illuminating the entire structure and fuelling its growth.