Discover 1-2

■ ■ ■

■ ■ ■ ■ ■■ (^)
■ ■ ■ ■ ■■ (^)
■ ■ ■ ■ ■■ (^)
■ ■ ■ ■ ■■ (^)
■ ■ ■ ■ ■■ (^)
■ ■ ■ ■ ■■ (^)
■ ■ ■ ■ ■■ (^)
■ ■ ■ ■ ■■ (^)
■ ■ ■ ■ ■■ (^)
■ ■ ■ ■ ■■ (^)
■ ■ ■ ■ ■■ (^)
■ ■ ■
■ ■ ■ ■ ■■ (^)
■ ■ ■ ■ ■■ (^)
■ ■ ■ ■ ■■ (^)
■ ■ ■ ■ ■■ (^)
■ ■ ■ ■ ■■ (^)
■ ■ ■ ■ ■■ (^)
■ ■ ■ ■ ■■ (^)
■ ■ ■ ■ ■■ (^)
■ ■ ■ ■ ■■ (^)
■ ■ ■ ■ ■■ (^)
■ ■ ■ ■ ■■ (^)
■ ■ ■ ■ ■■ (^)
■ ■ ■ ■ ■■ (^)
■ ■ ■ ■ ■■ (^)
■ ■ ■ ■ ■■ (^)
■ ■ ■
■ ■ ■ ■ ■■ (^)
■ ■ ■ ■ ■■ (^)
■ ■ ■ ■ ■■ (^)
■ ■ ■ ■ ■■ (^)
■ ■ ■ ■ ■■ (^)
■ ■ ■ ■ ■■ (^)
■ ■ ■ ■ ■■ (^)
■ ■ ■ ■ ■■ (^)
■ ■ ■ ■ ■■ (^)
■ ■ ■ ■ ■■ (^)
■ ■ ■ ■ ■■ (^)
■ ■ ■ ■ ■■ (^)
■ ■ ■ ■ ■■ (^)
■ ■ ■ ■ ■■ (^)
■ ■ ■ ■ ■■ (^)
■ ■ ■
■ ■ ■ ■ ■■ (^)
■ ■ ■ ■ ■■ (^)
■ ■ ■ ■ ■■ (^)
■ ■ ■ ■ ■■ (^)
■ ■ ■ ■ ■■ (^)
■ ■ ■ ■ ■■ (^)
■ ■ ■ ■ ■■ (^)

92

93

January/February 2018^ DISCOVER^87

FROM LEFT: NICK ROMANENKO/RUTGERS UNIVERSITY; NASA; MATTIAS KARLÉN

❯ 

NEW TESTS ON A MOON

ROCK brought back by

Apollo 15 reveal surprising

evidence for a magnetic field baked

into the rock between 1 billion and

2.5 billion years ago.

Scientists knew the moon hosted

a powerful magnetic field until

about 3.6 billion years ago, when it

seemed to abruptly shut off. But the

new finding, published in August in

Science Advances, extends the moon’s

magnetic life by more than a billion

years, though at a shadow of its former self.

The work of Rutgers University researcher Sonia Tikoo

and her team was twofold: They argon-dated the rock, and

separately used a magnetometer to measure the magnetic

field recorded within the rock at the time it formed.

Researchers speculate that one activity — perhaps Earth’s

tidal tug — might have powered the moon’s young and

strong magnetic field, while a different mechanism — such as

the moon’s slow cooling — could have taken over and caused

the moon’s dim but persistent field later on.  KOREY HAYNES

The Moon’s

Magnetic Personality

❯ 

“WATER IS STRANGE,” says Anders

Nilsson, a physicist at Stockholm

University in Sweden. It expands

when it cools, for example, and it has a

strangely high boiling point. In a June

paper in the Proceedings of the National

Academy of Sciences, Nilsson and his team

described a new oddity they discovered:

Water can exist in at least two distinct

liquid states, each with different physical

properties.

It takes some coaxing to witness.

Nilsson has to bring water well below its

freezing point and then fiddle with the

pressure, eventually resulting in a liquid

that gets less dense as heat is added —

proof that liquid water can take on a

different physical form.

Nilsson even thinks this newly

discovered form of water may exist

naturally in tiny, shifting pockets within

ordinary room-temperature water. Now

he’s gathering more evidence. Even

humble water, essential for life and

thoroughly studied, still has secrets to tell.

 SHANNON PALUS

Watery Weirdness

Sonia Tikoo (top) studied

pieces of a moon rock

obtained during the

Apollo 15 mission (above)

to learn how long the

moon’s magnetic field

really lasted.