Astronomy

ASTRONEWS
Fast radio bursts (FRBs) are rare —
only 17 have ever been observed —
and as their name implies, they are
powerful but last only milliseconds.
Scientists have found most of them
buried in data well after their radio
waves actually strike a telescope dish.
This has limited researchers’
ability to perform any follow-up
observations and left the FRBs’ origins
a mystery. But on April 18, 2015,
an FRB struck Australia’s Parkes radio
telescope, which is part of the Survey
for Pulsars and Extragalactic Radio
Bursts (SUPERB).
The project alerted numerous
other radio telescopes to follow up
with the FRB, pinpointing its position
in the sky while its afterglow faded
over the next six days. Once they
knew where to look, astronomers
turned the Subaru telescope in
Hawaii to the FRB’s location, and
revealed an elliptical galaxy 6 billion
light-years away as the source.
The shape of an FRB’s signal also
can tell astronomers how much
material their radio waves passed
through on their journey. By combining
that information for the first time
with a specific origin, astronomers
could compare the material “measured”
by the FRB to cosmological
models. Current models put the
X-RAY SUCCESS. Japan’s new orbiting X-ray observatory Hitomi, or “eye,” successfully launched in February and
began instrument tests and calibrations. Once complete, Hitomi will begin observing black holes and galaxy clusters.
Fast radio burst reveals missing matter
Tharsis volcanoes
made Mars tip over
Olympus Mons is our solar system’s reigning king of
volcanoes. It dwarfs Mount Everest in height and
dominates an area the size of Arizona. The
stratovolcano is so large that, given
past performance, it would take NASA’s
Opportunity rover more than 500 years
to drive around it.
But Olympus Mons is just one peak in
a larger region known as the Tharsis
Bulge. The plateau also packs Arsia
Mons, Pavonis Mons, and Ascraeus Mons.
Mars’ diminutive size deprived it of tectonic
plates, so the lava below Tharsis
just kept pushing its way up in one place
over vast geologic timescales.
A new study published online in
Nature March 2 models the emergence
of the Tharsis Bulge along with ancient
martian climate. The French-led research
rewrites the first billion years of Mars’ history. The scientists
show that, as this region emerged more than 3.7 billion
years ago, the movement of mass and the eruption
of gases forever changed Mars.
The new work concludes that Tharsis formed later and
took longer than previously suggested.
The scientists also say it was these volcanoes that
fueled martian precipitation with their water-rich gases
FOLLOWING UP. The images on the right show successive zooms of the Parkes radio
telescope field (left) that found the fast radio burst (FRB). The bottom-right image shows
the follow-up observation by the Subaru telescope. D. KAPLAN (UWM)/E. F. KEANE (SKAO)
universe at roughly 69 percent dark
energy, 26 percent dark matter, and
only 5 percent “ordinary” matter —
but half of even this ordinary matter
remains unseen by most surveys, and
this is known as the “missing matter”
problem. “The good news is our
observations and the model match.
We have found the missing matter,”
says Evan Keane, a project scientist
at the Square Kilometer Array and
lead scientist on the study, which
was published in Nature on
February 25. — K. H.
BULGING OUT. Olympus Mons
and its neighbors on the Tharsis
Bulge rose out of the martian surface
3.7 billion years ago, altering
the Red Planet’s rotation and pushing
regions near the poles toward
the equator. NASA/WIKIMEDIA COMMONS; NASA/
JPL-CALTECH /ASU – JMARS
and propped up the Red Planet’s early atmosphere. But by
the time the Tharsis volcanoes exhaled their last breath,
the bulge held as much mass as the dwarf planet Ceres.
Tharsis had grown so big that it changed the planet’s
rotation, and the once-wet region shifted south from the
pole toward its present position at the equator. With the
volcanic gases exhausted, Mars was left with a long, dry
winter that continues through to this day. — Eric Betz
QUICK TAKES
FIRST FREE FALL
LISA Pathfinder, the
European Space Agency’s
space-based tech demonstrator
for detecting gravitational
waves, achieved free
fall for its gold-platinum test
masses in February. The
move shows the force of
gravity can be isolated as the
spacecraft maneuvers
around the test masses.
•
PLANET SLEUTHS
Amateur astronomers found
a new planet in the Hyades
star cluster by searching
public Kepler data, and then
they got McDonald
Observatory astronomers to
confirm it. The Neptunesized
world, K2–25b, is one of
the largest known around a
red dwarf star.
•
DIM DETECTOR
Charged injection devices, a
new kind of camera, can capture
light from bright and
dim objects in one image.
The technique cuts off bright
pixels while allowing dimmer
ones to continue collecting
photons. The approach could
revolutionize exoplanet
imaging.
•
R.I.P. PHILAE
Silent since July 9, 2015,
the European Space
Agency’s Philae lander was
finally pronounced dead on
Comet 67P/Churyumov-
Gerasimenko on February 12.
Despite its tumbled landing
that blocked solar power,
Philae still successfully finished
most of its scientific
goals.
•
THE LIGHT STUFF
A new study published in
Science Advances shows that
Earth’s core contains more
light elements like hydrogen,
sulfur, and silicon than previously
thought. The research
suggests these elements
make up some 5 to 10 percent
of our planet’s innards.
•
SHAPE SHIFTING
Earth’s Van Allen Belts —
electron swarms stretching
far from our planet — might
take a different shape than
previously thought, according
to new work in the
Journal of Geophysical
Research. The shape is vital
knowledge for protecting
earthly technology from
solar storms. — E. B.
WWW.ASTRONOMY.COM 11