What word do scientists use to describe the most ginormous star ever discovered? Published July 21, 2010 If you find something that’s bigger than you thought was physically possible, how would you describe it? You start with what you already have, which is R136a1, the equivalent of a cosmic ZIP code. The R stands for Radcliffe Observatory, which located the star in the first place (long before anyone knew its immensity.) Massive isn’t the same thing as “big” in astronomy. Mass is roughly equivalent to weight, and R136a1 is hefty: it once weighed 320 times as much as our sun (Sol.) That was when it was born. Because of its density, the star is unstable and part of its mass is constantly coming apart. (Insert your own jokes about the other kinds of stars coming apart.) R136a1 is what astrophysicists call a hypergiant. The names for largest of the large are as follows: subgiants, giants, bright giants supergiants and the densest, hypergiants. As faithful readers of this blog know, we don’t shy away from explanations of complex systems. The arcanum of stellar density, however, defies reasonable explication. The mythological basis of “giant” is a little more down to Earth. The violent outbursts of hypergiants echo the primal, savage Greek tale of the Giants, the children of Gaea and Uranus before Zeus and other Olympians. Many mythologies feature battles between huge human-like creatures and gods, but the Greek gigantes form the basis for the English word. The fight is called the gigantomachy. Add hyper, Greek for “over, beyond, overmuch, above measure,” and you have a ten-letter word worthy of such a brobdingnagian star. As if R136a1 hasn’t already impressed with you with its astronomical and etymological pedigree, consider the location of the hypergiant; the Tarantula Nebula, in the Large Magellanic Cloud. That’s the hippest home for a star since Hercules.