Hidden amid these colorful swirls are a bunch of jerks that could
mess with your phone’s maps app. But thanks to this vivid computer
simulation of our planet’s core, published recently in Nature
Geoscience, researchers are finally able to model and explain these
so-called geomagnetic jerks. The long-mysterious phenomena,
discovered in 1978, can introduce errors in technologies tied to
Earth’s magnetic field, including satellites and power grids.
Just beyond Earth’s solid inner core (center), the circulation of
molten metals shapes our planet’s magnetic field. Over centuries,
a slow and steady transfer of energy through convection — hotter
materials (red) rising as cooler materials (blue) sink — gradually
shifts the field (orange). However, sometimes sudden, unpredictable
changes occur in a fraction of the time. These are the jerks.
Using the new simulation, researchers were able to link
geomagnetic jerks to a type of rapid energy wave. Unlike
convection’s circular movement, these waves reach the core’s
surface like a tsunami, leading to a fast jerk in the magnetic field.
Understanding what creates the phenomena may help scientists
better predict them, and potentially limit the mayhem they can
cause. — ANNA GROVES
“What I see here is a cleaner, smar ter, safer
and cheaper world. It’s possible.”
— University of Oxford economist Matt Ives, on the potential adjustments the global economy
could make in response to climate change
What a Jerk
A
U
B
E
R
T
E
T
A
L
.
/
I
P
G
P
/
C
N
R
S
P
H
O
T
O
L
I
B
R
A
R
Y
SEPTEMBER/OCTOBER 2019
.
DISCOVER 21