Eagle Nebula 'Pillars of Creation' (1995)

These eerie, dark pillar-like structures are actually columns of cool interstellar hydrogen gas and dust that are also incubators for new stars. The pillars protrude from the interior wall of a dark molecular cloud like stalagmites from the floor of a cavern.

They are part of the Eagle Nebula (also called M16 — the 16th object in Charles Messier's 18th century catalog of "fuzzy" objects that aren't comets), a nearby star-forming region 6,500 light-years away in the constellation Serpens.

The pillars are in some ways akin to buttes in the desert, where basalt and other dense rock have protected a region from erosion, while the surrounding landscape has been worn away over millennia.

In this celestial case, it is especially dense clouds of molecular hydrogen gas (two atoms of hydrogen in each molecule) and dust that have survived longer than their surroundings in the face of a flood of ultraviolet light from hot, massive newborn stars (off the top edge of the picture). This process is called photoevaporation.

This ultraviolet light is also responsible for illuminating the convoluted surfaces of the columns and the ghostly streamers of gas boiling away from their surfaces, producing the dramatic visual effects that highlight the three-dimensional nature of the clouds.

The tallest pillar (left) is about 4 light-years long from base to tip. As the pillars themselves are slowly eroded away by the ultraviolet light, small globules of even denser gas buried within the pillars are uncovered.

The picture was taken on April 1, 1995, with the Hubble Space Telescope's Wide Field and Planetary Camera 2. The color image is constructed from three separate images taken in the light of emission from different types of atoms. Red shows emission from singly ionized sulfur atoms. Green shows emission from hydrogen. Blue shows light emitted by doubly ionized oxygen atoms.

Credit: NASA, ESA, STScI, J. Hester and P. Scowen (Arizona State University)