Eta Carinae: Herschel noted the Ancient 'Great Eruption'

In the 1830s, astronomer Sir John Herschel noticed an especially bright star in the southern sky while conducting a survey from Cape Town, South Africa.

He dutifully sketched the region where the star appeared, particularly noting a dark ring in the upper part of the Carina Nebula that resembled a keyhole (see image, left).

Within a few years, however, that star had so faded in brightness that Herschel's telltale keyhole was barely visible.

Today we know that Herschel's bright star was Eta Carinae, experiencing a sudden burst of brightness thanks to a "supernova imposter" event, in which the star system shed a whopping 20 solar masses worth of outer shell.

You can still see the remnant of this stellar explosion in the Homunculus Nebula. It's called that because Argentine astronomer Ernest Gaviola, who first observed it in 1950, thought it looked like a human figure, with a head, legs and folded arms.

There is even evidence that Australian aborigines may have spotted the Great Eruption around the same time, according to a paper that appeared last year in the Journal for Astronomical History and Heritage.

Co-author Duane Hamacher maintains that the Boorong people of northwestern Victoria were aware of celestial objects and cast them as characters in their oral stories of the Dreaming -- including the eruption of Eta Carinae.