ASTRONEWS
WWW.ASTRONOMY.COM 19QUARK SOUP. Physicists created ultra-hot droplets of the quark-gluon plasma (QGP) that filled the entire
universe during its first few milliseconds, showing QGP flows like a near-frictionless fluid.On December 31, OSIRIS-REx made
history a staggering 1.2 billion
miles (2 billion kilometers) from
Earth when the NASA mission
entered orbit around asteroid
Bennu — the smallest object
ever circled by a spacecraft.
After reaching Bennu on
December 3, OSIRIS-REx closed in
to orbit as close as 0.9 mile (1.24 km)
above its surface. During this short
orbital phase, which lasted until
February, the mission sent a slew
of data back to Earth.
OSIRIS-REx has confirmed
ground-based predictions about
the distant asteroid. As expected, its
boulder-rich surface is porous and
blue, stretching nearly 2,000 feet
(510 meters) in diameter. Most
exciting: The mission found traces
of ancient water on the asteroid.On Bennu’s surface, the craft
discovered clay that’s chock-full
of hydrated minerals, which sug-
gest that the asteroid interacted
with liquid water in the distant
past. Since Bennu’s surface is too
small to house water on its own,
researchers think the liquid instead
pooled up on the larger body from
which Bennu broke off.
By identifying water on aster-
oids like Bennu, which are believed
to have transported it throughout
our solar system, researchers can
get a better idea of how water may
have spread to a young Earth.
Scientists won’t have to study
this hydrated material from afar,
either. In 2020, OSIRIS-REx will blast
into the asteroid’s surface and col-
lect pieces small enough to bring
back to Earth in 2023. — A.J.OSIRIS-REx, meet Bennu
Chandra Observatory serves up six colorful wonders
CLOSE-UP. OSIRIS-REx snapped this picture of Bennu with its PolyCam imager
from a distance of about 50 miles (80 km). The craft continued to approach the
asteroid, whose exterior is strewn with boulders, and eventually entered an orbit
that took it within less than a mile of the surface. NASA/GSFC/UNIVERSITY OF ARIZONACOSMIC SAMPLER. NASA’s Chandra X-ray Observatory teamed up with fellow
telescopes to help create this mosaic of celestial treats. These images mix Chandra’s
X-ray observations with other types of light. The top left image shows a colorful
supernova remnant in the Small Magellanic Cloud, supplemented with optical light
from NASA’s Hubble Space Telescope and the Very Large Telescope (VLT). At middle
top is the Abell 370 galaxy cluster, with hot, X-ray-emitting gas shown in blue.
The top right image, which includes optical data from Arizona’s Mount LemmonSkyCenter, shows the Lagoon Nebula (M8), a colossal star-forming cloud 4,
light-years away. On the bottom left is an X-ray view of the famous Orion Nebula
(M42). To its right is the Triangulum Galaxy (M33), with objects such as neutron
stars and black holes highlighted in pink X-ray light. At bottom right is Abell 2744,
3.5 billion light-years from Earth. Combined with radio data from the Very Large
Array and optical light from the VLT and Subaru Telescope, the image shows the
glowing aftermath of a cosmic crash involving four smaller galaxy clusters. — A.J.NASA/CXC/SAO