In 1995, the world was astounded by the beautiful Hubble Space Telescope images of the Eagle Nebula, a cloud of interstellar gas and dust 7,000 light-years from Earth. Let's take a look at this intriguing region.
What is the Eagle Nebula?
Also known as M16, the Eagle Nebula is a 5.5 million-year-old cloud of molecular hydrogen gas and dust stretching approximately 70 light years by 55 light years. Inside the nebula, gravity pulls clouds of gas together to collapse inward. If enough gas is present, nuclear fusion is ignited in the center, and the compact cloud becomes a shining star. The Eagle Nebula is thought to have several star-forming regions within it.
The gas and dust that ultimately collapsed into the sun four billion years ago likely resided in a structure similar to the Eagle Nebula. [Spectacular Photos From the Revamped Hubble Telescope]
Where is the Eagle Nebula?
The Eagle Nebula lies 6,500 light-years away in the inner spiral arm of the Milky Way next to our own, the Sagittarius or Sagittarius-Carina Arm. When viewing the sky, the stellar nursery is found within the constellation of Serpens, the Serpent.
The nebula is viewable with the low-powered telescopes readily available to amateur astronomers, or with a pair of binoculars. With such equipment, observers can see approximately twenty stars clearly, surrounded by gas, dust, and the light of other, dimmer stars. In good conditions, the three pillars may also be seen.
What are the Pillars of Creation?
One of the best-known pictures of the Eagle Nebula is the Hubble Space Telescope image taken in 1995, highlighting the "Pillars of Creation." The three columns contain the materials for building new stars, and stretch four light-years out into space. Newborn stars outside of the famous Hubble image are responsible for sculpting the pillars, using ultraviolet light to burn away some of the gas within the clouds.
In 2010, images of the pillars taken by NASA's Chandra X-ray Observatory peered inside the pillars to reveal only a handful of x-ray sources. Because new stars are supposed to be a hot bed of x-ray activity, scientists speculated that the star-forming days of the pillars were coming to an end. [VIDEO: Inside the Pillars of Creation]
Similarly, research from 2007 suggested that a stellar supernova six thousand years ago could have already blown the pillars out of formation and into space. Because light takes time to travel, it may be another thousand years before we can see their demise.
What are EGGs?
Evaporating gaseous globules, or EGGs, are dense pockets of gas that lie at the top of the columns. Some EGGs appear as tiny bumps in the surface, while others have been completely uncovered or cut off completely from the pillars.
Although some EGGs will collapse down into new stars, others lack sufficient gas to create a new stellar candidate.
The EGGs are about a hundred times the Earth's distance to the sun, so the solar system would fit comfortably inside most of them. They last ten thousand to twenty thousand years.
Discovery of the Eagle Nebula
When Swiss astronomer Philippe Loys de Chéseaux discovered the Eagle Nebula in the mid-eighteenth century, he only described the cluster of stars surrounding it. Charles Messier independently rediscovered it in 1764 as part of his catalog, dubbing it M16.
The first image of the nebula appears to have been made by American astronomer Edward Barnard, in 1895.
—Nola Taylor Redd