A huge sunspot on the far side of the sun is expected to face Earth this weekend, potentially hitting our planet with a geomagnetic storm.
The spot is so big that it changes the way the Sun vibrate, according to spaceweather.com. If the dark spot projects a drop of plasma onto Earth, it could disrupt our magnetic field, affecting GPS and communications satellites in near-Earth orbit as well as aircraft navigation systems. The National Oceanic and Atmospheric Administration (NOAA) Space Weather Prediction Center released a forecast for an unstable geomagnetic field around Earth on August 6-7, which could mean auroras, although it’s not yet clear whether it will become a full-fledged solar storm.
Sunspots are dark spots on the surface of the sun caused by strong 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 is continuously vibrating due to convection bubbles hitting the surface,” NASA’s Solar Dynamics Observatory (SDO) project scientist Dean Pesnell told Live Science in an email. Hot and cold bubbles continuously rising and falling inside the sun move energy, causing vibrations that can be detected by solar observatories like the SDO. The strong magnetic field of the sunspot slows down these vibrations traveling through the sun. As a result, observatories like the SDO can monitor sunspots on the far side of our host star through the delay of these vibrational waves, although they can only see its near side, Pesnell added.
“The larger the sunspot and the stronger the magnetic field, the greater this delay will be,” Pesnell said.
The telltale vibrational shifts appeared on a helioseismic map near the southeastern limb of the sun.
This weekend, the sunspot will turn towards Earth, which could potentially lead to solar flares — an intense burst of radiation in the sun’s atmosphere.
“We will likely see flares as the sunspot spins into view,” Pesnell said.
This solar activity could have an impact on the 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 onto Earth known as, coronal mass ejections (CME). “There is a filament heading towards the sunspot and so there could be coronal mass ejections,” Pesnell added.
“Solar flares and CMEs are the primary means by which solar activity affects Earth,” Pesnell said. “According to my work, higher levels of solar activity mean increased drag on near-Earth orbiting satellites – and satellite operators will lose revenue if this drag de-orbits an operating satellite.” Other possible effects of more severe “space weather” include disruption of communications and navigation in the polar regions – often used by intercontinental aircraft flights – and even power outages on Earth.
The sun has an 11-year cycle in which its activity waxes and wanes, with a distinct “solar maximum” and “solar minimum” when the number of sunspots is greatest and least numerous, respectively. The sun is now heading towards 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 in the sunspot cycle, Pesnell said.
Originally posted on Live Science.