Astronomy

ASTRONEWS

WWW.ASTRONOMY.COM 15

STATION SUCCESS. A Japanese cargo ship reached the International

Space Station on August 24 with supplies and a new electron telescope.

The inner solar system’s only dwarf planet took

astronomers by surprise when NASA’s Dawn

spacecraft arrived early this year. Many expect-

ed that impact craters on Texas-sized Ceres

would “relax” due to abundant ice thought to

lie just beneath its surface. Instead, they found

a heavily cratered world with few outer signs of

the hidden inner ice reservoir.

But that’s not the weirdest part. Ceres has an

enormous mountain — just one. At some 21,

feet (6,400 meters) in elevation, the pyramid-

shaped peak towers higher than Alaska’s Denali,

America’s highest mountain.

“The team is totally baffled by the mountain

at the present time,” Dawn Principal Investigator

Chris Russell says. “We don’t really see how the

mountain got made.”

Some early theories suggested a foreign

object impact, but the mountain looks like it’s

made from the same stuff as Ceres. Scientists

are also looking at volcanoes around the solar

system in search of similarities but have so far

come up mostly empty-handed. The mountain

does bear resemblance to some others — those

seen on Pluto.

“The heights of [Pluto’s] mountains, and the

shape of the mountains, look very similar to the

shape of our mountains,” Russell says. “There is

a story there, but we haven’t figured out what

the answer is.” — E. B.

Ceres’ lonely mountain puzzles Dawn team

Sunspots usually

occur in pairs or

clusters of opposite

magnetic polarity.

SOLAR FLAIR.

The Sun’s outer lay-

ers sport a variety of

transient features to

delight observers,

all tied to the Sun’s

tangled, twisted

magnetic field. These

phenomena appear

at slightly different

layers or stand out

best at different wave-

lengths, hence the

variety of images com-

bined here. ASTRONOMY:

LUANN BELTER/KOREY HAYNES,

AFTER NASA/SDO (FILAMENT, CORO-

NAL HOLE, FLARE, SUNSPOT); ESA/

NASA/SOHO (PROMINENCE)

WHAT’S

THAT

THING ON

THE SUN?

PUZZLING PYRAMID. Ceres’ asteroid belt home
means it’s hit regularly by debris. However, astrono-
mers don’t think an impact can explain this mountain.

PEAKABOO. Ceres has but one mountain. Mysteri-

ously, it vaults 4 miles (6 kilometers) above the dwarf

planet’s plains. NASA/JPL-CALTECH/UCLA/MPS/DLR/IDA

FAST

FAC T

Coronal

hole

Flare Filament Sunspot Prominence