Almost 20 years ago, the Hubble Space Telescope took a breathtaking image that would soon become one of the most famous pictures in astronomy. That image was of the iconic Pillars of Creation; towering, ghost-like clouds of gas and dust, bathed in the blazing light from a cluster of newborn stars within the Eagle Nebula, or Messier 16. Now, in honor of the instrument’s 25th year in orbit, astronomers have revisited this sublime celestial landscape and captured its evocative features in an unimaginable level of detail.
The original image, snapped back in 1995, was captured using the Hubble’s Wide Field and Planetary Camera 2. It showed us three columns of cool, interstellar hydrogen gas and dust, drenched in scorching UV radiation from young stars. These trunk-like formations protrude from the interior wall of a dark molecular cloud, much like stalagmites jut out from the floor of a cave.
While it's not unusual to observe striking features such as these in star-forming regions, the Eagle Nebula’s structures are unquestionably the most haunting and captivating imaged so far. It’s therefore no surprise that the original portrait quickly became a worldwide sensation, appearing on everything from book covers to bed sheets, postage stamps to t-shirts. Not only that, but the color scheme—ionized oxygen in blue, hydrogen in green and sulfur in red—has been repeated in an abundance of cosmic images since. “We colored it that way not because it was pretty, but because it told you something about the physics,” said Paul Scowen, one of the scientists responsible for the image, “although it was pretty.”
Now, Scowen and his colleagues have used the Hubble’s newer Wide Field Camera 3, installed in 2009, to capture Messier 16’s iconic structures in a staggering level of detail. This new installation has twice the resolution of the earlier camera, providing us with a wider and crisper view. Alongside treating us to a jaw-dropping visible-light image, Hubble also snapped the celestial scene in infrared, which allows us to peer through much of the muddying clouds of dust and gas that obscure the background. This transforms the familiar bronze pillars into dark wisps of smoke set against a twinkling backdrop of stars. Here, we can see previously masked newborn stars that are in the process of formation.
The Pillars of Creation may have earned this name because of the intense rates of star formation observed within this region, but the new image showcases that they are also columns of destruction. The material within these clouds is gradually being chipped away by a harsh combination of UV light from young stars and strong winds from neighboring massive stars. This is highlighted by the milky haze that we see around the sharp edges of the pillars, which is material that is being evaporated away as a result of the intense heat radiating from young stars.
Alongside spoiling our eyes with an even more beautiful view, snapping this landscape 20 years apart helps astronomers understand how the region is changing over time. Although Hubble scientists have only had a short amount of time to study the image so far, they have already picked up some subtle differences. Some of the jets of gas, for example, have moved.