Living where we do, it can be hard to tell how ordinary our Sun is, shining dimly in our ordinary galaxy. Then comes something to remind us. This time it is a colossal supernova, called SN 2006gy, the brightest exploding star ever recorded. First observed last September, this one lies about 240 million light-years from us in the constellation Perseus. The explosion was perhaps 100 times more powerful than an ordinary supernova, and the star that exploded may have been 150 times the Sun’s mass.

What we are witnessing in SN 2006gy may be the making of the very atomic stuff out of which we ourselves are made. We are used to the notion that looking at the stars means looking back in time. Looking at SN 2006gy may mean looking at one of the fundamental processes in a much earlier universe. Astronomers point to an analogous star in our own galaxy, Eta Carinae, about 7,500 light-years away. It is similar in size, and similar in instability, to the star that turned, dying, into SN 2006gy. There is a possibility that Eta Carinae may itself die. It is perhaps unwise to hope for grand celestial events in one’s lifetime. Stunning discoveries from the past should be enough. But it is tempting to wonder what such a nearby supernova, on such a scale, would be like, how it would be to live under such an altered sky.