Explanation:
Awash in a sea of
plasma and anchored in
magnetic
fields, sunspots are planet-sized,
dark islands in
the
solar photosphere, the bright surface of the Sun.
Dark
because they are slightly cooler than the surrounding surface,
this group of sunspots is captured in a close-up
telescopic snapshot from July 11.
The field of view spans nearly 100,000 miles.
They lie in the center of active region AR1520, now crossing the
Sun's visible face.
In fact, an
X-class solar flare and
coronal mass ejection erupted
from AR1520 on July 12, releasing some of the energy stored in the
region's twisted magnetic fields.
Headed this way, the coronal mass ejection is expected to
arrive today and may trigger
geomagnetic storms.
As a result, some weekend auroral displays could grace
planet Earth's skies along with
Sunday's
predawn conjunction of bright planets and crescent Moon.
