 El Gordo is a cluster of hundreds of galaxies that existed when the universe was 6.2 billion years old. It's the most massive cluster known to exist at that time. This image was produced by a combination of Hubble and web data. It contains 60 lensed arcs, from galaxies billions of light years further away than El Gordo. Here's a sample of the numbering system used to identify each object studied. There are over 180 points of interest. Note the long, pencil-thin line below and left of center. Known as laflaca, the thin one, it is extremely thin and one of the longest arcs known. One of the most striking features is the bright red arc at the upper right. It's called the fish hook. The light from this galaxy took 10.8 billion years to reach Earth. Its distinctive red color is due to a combination of reddening from dust within the galaxy itself and cosmological redshift due to space expansion. In our gravitational lensing segment of the How Fast is it video book, we covered how knowledge of the lens properties and critical curves of the foreground cluster enables astronomers to reconstruct the source galaxy's size and shape. Using these techniques, astronomers were able to determine that the background galaxy is disc-shaped and 26,000 light years in diameter. That's about one-fourth the size of the Milky Way. Another fascinating find in El Gordo is the first individual red supergiant star beyond one billion light years from Earth. Until now, all previous stars discovered at high redshifts have been hot blue stars. Blue juice and antaries are the brightest and best known red supergiants in our Milky Way galaxy. This star is named Quiller. Such stars at high redshift are only detectable using the infrared filters and sensitivity of the web telescope. The outer yellow circles mark the positions of two counter-images of a source that brackets the position of the critical curve. The white central circle marks Quiller.