Seeing Beyond The Light
In August 1999, NASA's Chandra X-ray
Observatory opened for business. Six years later, it continues to
achieve scientific firsts.
"When Chandra opened its sunshade doors for the first time, it
opened the possibility of studying the X-ray emission of the
universe with unprecedented clarity," said Chandra project
scientist Dr. Martin Weisskopf of NASA's Marshall Space Flight
Center in Huntsville, Ala. "Already surpassing its goal of a
five-year life, Chandra continues to rewrite textbooks with
discoveries about our own solar system and images of celestial
objects as far as billions of light years away."
Based on the observatory's outstanding results, NASA
Headquarters in Washington decided in 2001 to extend Chandra's
mission from five years to ten. During the observatory's sixth year
of operation, auroras from Jupiter, X-rays from Saturn, and the
early days of our solar system were the focus of Chandra
discoveries close to home - discoveries with the potential to
better understand the dynamics of life on Earth.
Jupiter's auroras are the most spectacular and active auroras in
the solar system. Extended Chandra observations revealed that
Jupiter's auroral X-rays are caused by highly charged particles
crashing into the atmosphere above Jupiter's poles. These results
gave scientists information needed to compare Jupiter's auroras
with those from Earth, and determine if they are triggered by
different cosmic and planetary events.
Mysterious X-rays from Saturn also received attention, as
Chandra completed the first observation of a solar X-ray flare
reflected from Saturn's low-latitudes, the region that correlates
to Earth's equator and tropics.
This observation led scientists to conclude the ringed planet
may act as a mirror, reflecting explosive activity from the sun.
Solar-storm watchers on Earth might see a surprising benefit. The
results imply scientists could use giant planets like Saturn as
remote-sensing tools to help monitor X-ray flaring on portions of
the sun facing away from Earth's space satellites.
Another Chandra discovery - gleaned from the deepest X-ray
observation of any star cluster - offered insights on Earth's
survival in its infancy.
Chandra's focus was the Orion Nebula, which contains at least 1,400
young stars, 30 that are prototypes of the early sun. Using
Chandra, scientists learned these young stars produce violent X-ray
flares much more frequently and energetically than anything seen
today from our 4.6 billion-year-old sun. This implies super-flares
torched our young solar system and likely affected the
planet-forming disk around the early sun - enhancing the survival
chances of Earth.
"Space is a harsh environment with extreme temperatures, harmful
radiation and none of the protection offered by Earth's
atmosphere," said Chandra Program Manager Keith Hefner of the
Marshall Center. "Ironically, the fact that our atmosphere absorbs
harmful X-rays is the very reason for Chandra's existence. Getting
outside the absorbing atmosphere of the Earth requires space-based
observatories, and viewing the universe in multiple wavelengths is
necessary to fully study cosmic events. Chandra's continued
outstanding performance after six years of operation under such
harsh conditions is evidence that it is, indeed, an engineering
In its sixth year, Chandra also continued to build on its
growing list of discoveries involving black holes. This included
finding the most powerful eruption seen in the universe, generated
by a supermassive black hole growing at a remarkable rate. The
eruption - which has lasted for 100 million years and is still
going - has generated the energy equivalent to hundreds of millions
of gamma-ray bursts. This discovery illustrated the enormous
appetite of large black holes, and the profound impact they have on
Other recent discoveries include confirming the existence of
weight limits for supermassive black holes, finding evidence for a
swarm of black holes near the galactic center and gathering more
data supporting the existence of mid-sized black holes.