Hubble: Pillars of Creation are also Pillars of Destruction
 
Jan. 7, 2015:   Although NASA's Hubble Space Telescope has taken many
breathtaking images of the universe, one snapshot stands out from the rest:
the iconic view of the so-called "Pillars of Creation." The jaw-dropping
photo, taken in 1995, revealed never-before-seen details of three giant
columns of cold gas bathed in the scorching ultraviolet light from a cluster
of young, massive stars in a small region of the Eagle Nebula, or M16.
 
In celebration of its upcoming 25th anniversary in April, Hubble has revisited
the famous pillars, providing astronomers with a sharper and wider view. 
Although the original image was dubbed the Pillars of Creation, the new image
hints that they are also "pillars of destruction."
 
http://www.nasa.gov/sites/default/files/p1501ay.jpg
 
Astronomers using NASA's Hubble Space Telescope have assembled a bigger and
sharper photograph of the iconic Eagle Nebula's "Pillars of Creation". Credit:
NASA/ESA/Hubble Heritage Team (STScI/AURA)/J. Hester, P. Scowen (Arizona State
U.)
 
"I'm impressed by how transitory these structures are," explains Paul Scowen
of Arizona State University in Tempe. "They are actively being ablated away
before our very eyes. The ghostly bluish haze around the dense edges of the
pillars is material getting heated up and evaporating away into space. We have
caught these pillars at a very unique and short-lived moment in their
evolution." Scowen and astronomer Jeff Hester, formerly of Arizona State
University, led the original Hubble observations of the Eagle Nebula.
 
The original 1995 images were taken in visible light.  The new image includes
near-infrared light as well. The infrared view transforms the pillars into
eerie, wispy silhouettes seen against a background of myriad stars. That's
because the infrared light penetrates much of the gas and dust, except for the
densest regions of the pillars. Newborn stars can be seen hidden away inside
the pillars.
 
The infrared image shows that the very ends of the pillars are dense knots of
dust and gas. They shadow the gas below them, keeping the gas cool and
creating the long, column-like structures. The material in between the pillars
has long since been evaporated away by the ionizing radiation from the central
star cluster located above the pillars.
 
At the top edge of the left-hand pillar, a gaseous fragment has been heated up
and is flying away from the structure, underscoring the violent nature of
star-forming regions. "These pillars represent a very dynamic, active
process," Scowen said. "The gas is not being passively heated up and gently
wafting away into space. The gaseous pillars are actually getting ionized, a
process by which electrons are stripped off of atoms, and heated up by
radiation from the massive stars. And then they are being eroded by the stars'
strong winds and barrage of charged particles, which are literally
sandblasting away the tops of these pillars."
 
When Scowen and Hester used Hubble to make the initial observations of the
Eagle Nebula in 1995, astronomers had seen the pillar-like structures in
ground-based images, but not in detail. They knew that the physical processes
are not unique to the Eagle Nebula because star birth takes place across the
universe. But at a distance of just 6,500 light-years, M16 is the most
dramatic nearby example - as the team soon realized.
 
[Same as JPG above]
 
The original 1995 image was beautiful. Compare this view to the 2014 image in
a side-by-side montage
 
As Scowen was piecing together the Hubble exposures of the Eagle, he was
amazed at what he saw. "I called Jeff Hester on his phone and said, `You need
to get here now,'" Scowen recalled. "We laid the pictures out on the table,
and we were just gushing because of all the incredible detail that we were
seeing for the very first time."
 
The first features that jumped out at the team in 1995 were the streamers of
gas seemingly floating away from the columns. Astronomers had previously
debated what effect nearby massive stars would have on the surrounding gas in
stellar nurseries. "There is the only one thing that can light up a
neighborhood like this: massive stars kicking out enough horsepower in
ultraviolet light to ionize the gas clouds and make them glow," Scowen said.
"Nebulous star-forming regions like M16 are the interstellar neon signs that
say, `We just made a bunch of massive stars here.' This was the first time we
had directly seen observational evidence that the erosionary process, not only
the radiation but the mechanical stripping away of the gas from the columns,
was actually being seen."
 
By comparing the 1995 and 2014 pictures, astronomers also noticed a
lengthening of a narrow jet-like feature that may have been ejected from a
newly forming star. The jet looks like a stream of water from a garden hose.
Over the intervening 19 years, this jet has stretched farther into space,
across an additional 60 billion miles, at an estimated speed of about 450,000
miles per hour.
 
Our sun probably formed in a similar turbulent star-forming region. There is
evidence that the forming solar system was seasoned with radioactive shrapnel
from a nearby supernova. That means that our sun was formed as part of a
cluster that included stars massive enough to produce powerful ionizing
radiation, such as is seen in the Eagle Nebula. "That's the only way the
nebula from which the sun was born could have been exposed to a supernova that
quickly, in the short period of time that represents, because supernovae only
come from massive stars, and those stars only live a few tens of millions of
years," Scowen explained. "What that means is 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."
 
Credits:
Production editor: Dr. Tony Phillips | Credit: Science@NASA
 
More information:
 
The Hubble Space Telescope is a project of international cooperation between
NASA and the European Space Agency. NASA's Goddard Space Flight Center in
Greenbelt, Maryland, manages the telescope. The Space Telescope Science
Institute (STScI) in Baltimore conducts Hubble science operations. STScI is
operated for NASA by the Association of Universities for Research in
Astronomy, Inc., in Washington.
 
NASA is exploring our solar system and beyond to understand the universe and
our place in it. We seek to unravel the secrets of our universe, its origins
and evolution, and search for life among the stars. Today's announcement
shares the discovery of our ever-changing cosmos, and brings us closer to
learning whether we are alone in the universe.
 
 
Regards,
 
Roger

--- D'Bridge 3.99
 * Origin: NCS BBS - Houma, LoUiSiAna (1:3828/7)