The Hubble and Keck Telescopes assemble a 3D view of a giant galaxy

A photo of the huge elliptical galaxy M87 [left] is compared to its three-dimensional shape as gleaned from meticulous observations made with the Hubble and Keck telescopes [right]. Because the galaxy is too far away for astronomers to employ stereoscopic vision, they instead followed the motion of stars around the center of M87, like bees around a hive. This created a three-dimensional view of how stars are distributed within the galaxy.

Astronomers picked one of the nearest ellipticals to Earth, M87, located 54 million light-years away in the heart of the vast Virgo cluster of galaxies. By following the motion of stars around the center of M87, like bees around a hive, they’ve measured that the galaxy is potato-shaped. It not only has a long and short axis, which defines an ellipse on a piece of graph paper, but they measured a third axis which helps define the three-dimensionality. The geometric term is: triaxial.