Astronomy - USA (2020-08)

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Astronomers

see our Sun

spin threads

of plasma

The Sun’s magnetic field blasts

charged particles into space.

On Earth, we experience this

steady stream as the solar

wind, which fuels aurorae.

Our planet also deals with

fallout from occasional strong

outbursts. However, for all of

the downstream effects we

experience thanks to the Sun’s

magnetic field, its true nature

remains an elusive mystery.

Now, new images are bring-

ing scientists one step closer

to understanding this impor-

tant phenomenon. For the first

time, astronomers have cap-

tured the extremely fine details

of our star’s magnetic field

— details too intricate to have

previously been seen. The new

research was published April 1

in The Astrophysical Journal.

The close-ups were taken

by NASA’s High Resolution

Coronal Imager, or Hi-C, which

is not aboard a spacecraft.

Instead, it’s briefly carried aloft

by a suborbital-flight rocket

before returning to Earth. Once

in the air, the telescope zooms

in on solar features as small

as 43 miles (70 kilometers)

across, or just 0.01 percent the

width of the entire Sun. That

makes these photos of the

Sun’s atmosphere the highest-

resolution versions ever taken.

The new images show never-

before-seen bundles of million-

degree plasma threading

across the Sun’s atmosphere,

tracing the star’s magnetic field

itself. Each of these threads is

only about 310 miles (500 km)

across, roughly the driving

distance between Chicago

and Cleveland.

Now that scientists have

actually seen these delicate

threads, the next step is to

understand them. Researchers

aren’t yet sure what generates

the Sun’s fine magnetic field

lines. They also don’t know

how the field lines affect things

like the solar wind and coronal

mass ejections, with the latter

capable of pumping out billions

of tons of material into space.

The international Hi-C team

is already working to plan the

telescope’s next suborbital

flight, where they hope to

combine their observations

with data taken simultaneously

by the Parker Solar Probe and

Solar Orbiter. — A.K.

FINE THREADS. New images

show delicate magnetic field

lines, haloed by scalding

plasma, sprouting from seemingly

featureless regions of the Sun. UN

IVE

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