A sharp view of the Pillars of Creation was released in January 2015, in celebration of Hubble’s 25th anniversary. Credit: NASA, ESA, and the Hubble Heritage Team (STScI/AURA)

Among the vast library of Hubble’s images, one particular icon stands out: the Pillars of Creation. The image—depicting columns of greenish-brownish gas rising out of a ghostly mist against a glowing green universe speckled with bright infant stars—has permeated the public’s collective mind ever since its release in 1995.

The original Pillars of Creation image, released in 1995, is Hubble’s most iconic image. Credit: NASA, J. Hester, and P. Scowen

Although pillar-like structures of gas are not uncommon in star formation—all stars emerge within massive clouds of cosmic gas and dust—Hubble’s Pillars of Creation presented the first detailed, dramatic view of stellar birth. Scientists achieved this detail because the Eagle Nebula, where the pillars reside, is relatively close by—a mere 7000 light-years away from the Sun. The image, captured by Hubble’s Wide Field Camera 2 (WFC2), provided scientists with the first observational evidence of early processes in star formation within massive clouds of gas.

Within the billowing pillars, scientists got a glimpse of embryonic stars—before they were truly stars. Scientists also saw that fierce, ionizing winds from nearby infant stars were blowing away the surrounding cosmic dust in a process called photoevaporation. Thus, the Pillars of Creation, when viewed another way, could also be deemed the Pillars of Destruction, scientists say; these ionizing winds, which strip electrons away from atoms, tear away the material needed for a growing star.

A Fresh View

In January 2015, NASA released a new Pillars of Creation image—this time using Hubble’s Wide Field Camera 3 (WFC3). WFC3 is much more sensitive than its predecessor and can detect ultraviolet light. The new image provided an even sharper view of the pillars, revealing further destruction by infant stars’ ionizing winds.

A comparison of features in the newly released Pillars of Creation image with observations from the original image. Credit: NASA, ESA, and the Hubble Heritage Team (STScI/AURA)

By comparing the more recent image with the original, scientists spotted something new. A narrow jet of material seen in the original image has now grown, likely the result of an ejection by an infant star. Scientists estimate that the jet stretched more than 96 billion kilometers in the past 2 decades, traveling at a speed of more than 700,000 kilometers per hour.

Continuing Discoveries

The Pillars of Creation image inspires researchers to this day. Last week, a team of scientists from the European Southern Observatory (ESO) released a three-dimensional image of the pillars, giving new insight into their shape and orientation within space. Using an instrument attached to the Very Large Telescope at the Paranal Observatory in Chile, the researchers found that the left-hand pillar is oriented slightly behind the others, whereas its tip faces Earth. They also found that the left-hand pillar bears the brunt of the ionizing winds, making it appear brighter to us than the rest of the image.

ESO released an animation of its new data in the video below.

ESO scientists also spotted newly forming protostars that had been missed by previous Hubble images.

Lasting Legacy

Hubble was originally launched with a tiny error in its mirror that rendered images too blurry to use. Two years after astronauts fixed the error, NASA released the Pillars of Creation image, which captured the attention of the world.

The original image opened a door to the universe, not just to scientists and academics but to anyone who wanted to learn.

After years struggling to nurture a sense of wonder in space despite the underperforming space telescope, Hubble scientists finally could show the public what the instrument could do through this glimpse of stellar birth. The original image opened a door to the universe, not just to scientists and academics but to anyone who wanted to learn.

“There was a science story behind it that you could explain to Aunt Martha. It had to do with how we came into being,” Jeff Hester, one of the astronomers who worked on the image, told Pacific Standard.

Studying the Pillars of Creation in the Eagle Nebula could also give insight into our own galaxy, according to Paul Scowen of Arizona State University, a member of the original team that created the image. “When you look at the environment of the Eagle Nebula or other star-forming regions, you’re looking at exactly the kind of nascent environment that our Sun formed in,” he said in a press release.

—JoAnna Wendel, Staff Writer

Citation: Wendel, J. (2015), Hubble’s legacy: The pillars of creation, Eos, 96, doi:10.1029/2015EO029357. Published on 4 May 2015.

Text © 2015. The authors. CC BY-NC 3.0
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