The Hubble Space Telescope sends along the spirit of the season, spying a cosmic holiday wreath.
Just like your favorite seasonal ornament, the giant cloud of gas and dust lights up from within. Only in this case, the holiday glow comes from a massive variable star.
Located some 6,500 light years away from Earth, the super-giant star at the center of the image, RS Puppis, is in its death throes. The star weighs in with 10 times more mass than our sun, and is a whopping 200 times larger.
Because RS Puppis rhythmically pulses in brightness and energy—up to 15,000 times greater than our sun at its six week peak—it bathes the surrounding cocoon of reflective dust in waves of light rippling clear across the entire nebula. The phenomenon is known as a “light echo”.
“Even though light travels through space fast enough to span the gap between Earth and the Moon in a little over a second, the nebula is so large that reflected light can actually be photographed traversing the nebula,” said a statement on NASA’s website.
Keeping careful tabs on how the star’s light varies over time and how it drives light pulses across the entire dusty nebula, astronomers precisely measured the distance to RS Puppis—down to only an incredible 1% margin of error. The star will serve as an improved cosmic “yardstick”, according to the space agency, allowing observers to better gauge the distance to other celestial objects.