This eerie, dark structure, resembling an imaginary sea serpent's
head, is a column of cool molecular hydrogen gas (two
atoms of hydrogen in each molecule) and dust that is an incubator
for new stars. The stars are embedded inside finger-like
protrusions extending from the top of the nebula. Each "fingertip"
is somewhat larger than our own solar system.
The pillar is slowly eroding away by the ultraviolet light from
nearby hot stars, a process called "photoevaporation". As it
does, small globules of especially dense gas buried within the
cloud is uncovered. These globules have been dubbed
"EGGs" -- an acronym for "Evaporating Gaseous Globules". The
shadows of the EGGs protect gas behind them, resulting
in the finger-like structures at the top of the cloud.
Forming inside at least some of the EGGs are embryonic stars
-- stars that abruptly stop growing when the EGGs are
uncovered and they are separated from the larger reservoir of
gas from which they were drawing mass. Eventually the stars
emerge, as the EGGs themselves succumb to photoevaporation.
The stellar EGGS are found, appropriately enough, in the "Eagle
Nebula" (also called M16 -- the 16th object in Charles
Messier's 18th century catalog of "fuzzy" permanent objects
in the sky), a nearby star-forming region 7,000 light-years
away in the constellation Serpens.
The picture was taken on April 1, 1995 with the Hubble Space
Telescope 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: Jeff Hester and Paul Scowen (Arizona State University),
and NASA
Students for the Exploration and Development of Space
Created by R. Mark Elowitz
Maintained byGuy K. McArthu