DISTANT DISCOVERIES
COOLEST PLACE IN SPACE
Astronomers have identified the coldest place ever detected in space.
It is the gas blown away from a star in the latter stages of its life-cycle.
The so-called Boomerang Nebula, one of the youngest of its kind, has
been observed in minute detail by the Hubble Space Telescope (HST).
It seems that the central dying star has been expelling gas at a huge
rate. As that gas has expanded it has cooled to such a degree that it
is now even colder than the cosmic background radiation that bathes
all of space.
The young planetary nebula imaged by the HST is in the constellation
of Centaurus, 5,000 light-years from Earth. Planetary nebulae form around
bright, central stars when they expel gas in the last stages of their
lives.
In 1995, astronomers revealed that the Boomerang Nebula is the coldest
place in the Universe found so far outside a terrestrial laboratory.
With a temperature of -272 Celsius, it is only one degree warmer than
absolute zero.
Even the -270 C background radiation from the Big Bang that permeates
the cosmos is warmer than this nebula. The Boomerang Nebula is the only
object found so far that has a temperature lower than the background
radiation.
The recent Hubble image shows faint arcs and ghostly filaments embedded
within the diffuse gas of the nebula's lobes. It appears quite different
from other observed planetary nebulae. Researchers speculate that the
object is so young that it may not have had time to develop more familiar
structures.
The remarkable coolness of the gas clouds may be the result of an unusual
central star. The clouds appear to have been sculpted by a fierce 500,000
kilometer-per-hour wind blowing ultra-cold gas away from the dying central
star.
The dying star has been losing as much as one-thousandth of a solar
mass of material each year for perhaps a millennium. This is 10-100
times more than mass-loss seen in other similar objects.
It is the rapid expansion, and subsequent cooling, of the gas cloud
that has enabled it to become the coldest known region in the Universe.
Story from BBC NEWS:
http://news.bbc.co.uk/go/pr/fr/-/1/hi/sci/tech/2783941.stm
 JAPAN
LAUNCHES ASTEROID SAMPLE RETURN MISSION
A compact Japanese space probe embarked on an ambitious mission this
month bound for a series of close encounters with an almost equally
small asteroid to gather samples for return to Earth.
Liftoff of the M-5 rocket was from the Kagoshima Space Center. The
MUSES-C payload was placed into a transfer orbit within minutes of launch.
It marked the first flight of the M-5 since a launch over three years
ago failed to successfully loft an international observatory to orbit
due to a nozzle failure on the first stage.
The 1,166-pound MUSES-C spacecraft's trajectory is expected to culminate
with arrival in orbit around asteroid 1998 SF36, an object roughly 2,300
feet by 1,000 feet in dimensions.
After its arrival in June 2005, the satellite will orbit some 12 miles
above the surface of the space rock for several months conducting scientific
investigations before using its propulsion system to dip down in at
least three "touch-and-go" maneuvers that aim to gather up
to one gram of material from a variety of sites on the asteroid.
These sample collections consist of a tiny metal projectile fired toward
the surface at very close range, which will cause an impact crater and
debris from the asteroid to be trapped within a funnel that then will
feed the material into the chamber within the capsule that will return
to Earth.
MUSES-C is expected to be en route back to Earth by the end of 2005
after a five-month stay at 1998 SF36. Shortly before arrival, a 44-pound
re-entry section will jettison from the main spacecraft body and will
undergo a high-speed entry into the atmosphere before making a parachuted
touchdown in Australia in June 2007.
During the cruise phase of the mission, MUSES-C will be driven by a
cutting edge ion propulsion thruster that saves propellant.
The spacecraft also features a high technology autonomous control system
that will govern much of the final approach during the sample collection
runs because of the long communications lag between 1998 SF36 and Earth.
MUSES-C has gone through a number of setbacks since the project's
start, including launch vehicle failures and delays, the cancellation
of a NASA rover to be dropped on the target asteroid and a change in
destination.
The mission undertaken by Japan's Institute of Space and Astronautical
Science, if successful, will be the first to return material back to
Earth from an asteroid. NASA's Stardust satellite will soon be gathering
cometary dust that will come back to Earth, while the Genesis mission
is collecting solar wind samples.
Scientists say even just one gram of returned material could hold key
clues about the early solar system because asteroids hold some of the
best preserved and oldest matter in the solar system.
Carried aboard MUSES-C are also the names of 877,490 people etched
within a target marker that will be released on the surface of 1998
SF36 during each of the sample collection passes.
Source: SPACEFLIGHT NOW
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