The cosmic eruption came from Eta Carinae, a star about 7,500 light-years away from Earth that is one of the most massive stars in our Milky Way galaxy. It blazed into ultra-brightness in 1838, becoming the second-brightest star in the sky for 10 years in a rare celestial outburst later dubbed the "Great Eruption." The star later dimmed, and is now not even in the top 100 list of brightest stars.