2019-12-01_Astronomy

PLANET HUNTER

NASA’s TESS telescope completed

its first year of scanning the

southern sky for exoplanets in July,

and has since moved on to the

northern sky.

ERODING RODENTS

An international study found that

mice living in microgravity on the

International Space Station lost

bone mass in their legs, while mice

living in hypergravity (thanks to a

centrifuge) on Earth gained both

bone and muscle mass.

CASTAWAY

The crash landing of Israel’s

Beresheet Moon probe likely left

thousands of survivors stranded on

the Moon — specifically, tiny, hardy

creatures called tardigrades, which

were part of an experiment the

lander carried.

POSTMORTEM

University of Warwick-led

researchers have calculated that

the cores of dead planets can

survive 100 million to 1 billion years

after their stars have ballooned into

red giants, possibly providing a

glimpse into Earth’s future.

MARTIAN SCOUT

NASA’s unnamed Mars 2020 rover

will be equipped with the first

rotorcraft to fly on another planet.

However, the proof-of-concept

helicopter will not carry any

scientific instruments.

TOTAL ANNIHILATION

Astronomers have witnessed the

complete destruction of a star

that began life at some 200 solar

masses. The explosion, which

left no trace of its progenitor,

challenges theories about how

such massive stars die.

DEEP DIVE

The SETI Institute plans to

robotically explore Earth’s deep-sea

vents to practice hunting alien

life on worlds like Europa

and Enceladus. — J.P.

QUICK

TAKE S

WWW.ASTRONOMY.COM 11

The European Space Agency’s Mars Express spacecraft recently revealed the bleak yet

beautiful terrain of Terra Cimmeria in Mars’ southern highlands. The stunning new views

highlight valleys carved by liquid water that once flowed across the surface, windswept

dunes composed of sand and dust, and impact craters that run the gamut in size. Terra

Cimmeria is a particularly interesting region largely due to Eridania, a paleolake from Mars’

distant past, when liquid water was abundant in the southern highlands. Though the water

is now gone, its valleys and shorelines remain, as well as plenty of sediment rich in various

clay minerals. — ERICA NAONE, J.P.

The windswept craters of Mars

A COSMIC CLOCK

GLITCHES

Pulsars, the rapidly spinning cores

of dead stars, are some of the

universe’s most reliable rotators

— until they’re not. Astronomers

occasionally observe “glitches” in

about 5 percent of pulsars, during

which they speed up and brief ly

rotate faster. They believe glitches

occur when an inner layer of the

star suddenly sloshes outward.

When that layer hits the pulsar’s

outer crust, it causes the star to

spin faster before reverting to its

previous spin rate within seconds.

The Vela Pulsar, which lies

1,000 light-years away, glitches as

often as once every three years.

This composite image, which com-

bines optical and X-ray light, shows

the pulsar lurking inside the cloud

of gas and dust left over from when

its star went supernova more than

10,000 years ago. Vela’s most recent

glitch, observed in 2016, revealed a

surprise: The pulsar slowed down

brief ly just before the faster rotation

of the glitch kicked in. Astronomers

are now on the lookout for such

slow-down periods preceding

glitches to learn more about why

and how glitches happen in Vela

and other pulsars. — KOREY HAYNES, A.K.

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