A huge sunspot on the far side of the sun is set to face Earth this weekend,
potentially lashing our planet with a geomagnetic storm.
The spot is so big it's changing the way the sun vibrates, according to
spaceweather.com. If the dark spot hurls a blob of plasma at Earth, it could
disrupt our magnetic field, affecting GPS and communication satellites
orbiting close to Earth as well as airplane navigation systems. The National
Oceanic and Atmospheric Administration (NOAA) Space Weather Prediction Center issued a forecast for an unsettled geomagnetic field around Earth on
Aug. 6 and 7, which could means auroras, though whether it becomes a
full-blown solar storm is not yet clear.
Sunspots are dark patches on the surface of the sun that are caused by
intense magnetic fields. While this sunspot is on the far side of the sun,
scientists detected it by monitoring its effects on the sun’s vibrations.
"The Sun continually vibrates because of convection bubbles hitting the
surface,"Dean Pesnell, project scientist of NASA's Solar Dynamics
Observatory (SDO), told Live Science in an email. Hot and cool bubbles that
continually rise and fall inside the sun move energy around, causing
vibration that can be detected by solar observatories like the SDO.
The sunspot's strong magnetic field slows these vibrations, which travel
through the sun. As a result, observatories like the SDO can monitor
sunspots on our host star's far side by the delay in these vibrational
waves, despite only being able to see its near side, Pesnell added.
"The larger the sunspot and the stronger the magnetic field the larger this
delay will be," Pesnell said.
The telltale vibrational changes showed up in a helioseismic map near the
sun's southeastern limb.
This weekend the sunspot will turn to face Earth, which could potentially
lead to solar flares — an intense burst of radiation in the sun's
atmosphere.
"We will probably see flares when the sunspot rotates into view," Pesnell
said.
This solar activity could impact Earth. Solar flares can heat clouds of
electrically charged particles from the sun's upper atmosphere to enormous
temperatures, which can launch gigantic blobs of plasma at Earth known as,
coronal mass ejections (CMEs). "There is a filament heading in the direction
of the sunspot and so there might be some coronal mass ejections," Pesnell
added.
"Solar flares and CMEs are the major way solar activity affects the Earth,"
said Pesnell. "From my work, higher levels of solar activity mean increased
drag on satellites orbiting close to the Earth — and satellite operators
will lose income if that drag de-orbits a working satellite." Other possible
effects of more severe "space weather" include the disruption of
communications and navigation in the polar regions — often used by
intercontinental plane flights — and even power outages on Earth.
The sun has an 11 year cycle during which its activity waxes and wanes, with
a distinct "solar maximum" and "solar minimum" when the number of sunspots
are most and least numerous, respectively. The sun is now headed for a solar
maximum in 2024 or 2025. Lately, the sun has been more active than NASA predicted. CMEs are normal behavior for sunspots at this point of the
sunspot cycle, Pesnell said.
Originally published on
Live Science.
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Space & Astrophysics