Solar winds from the snapping of a gigantic "canyon of fire" filament on the Sun are set to slam into the Earth today (20 July) or tomorrow (21 July), triggering a weak G1 geomagnetic storm.
Then, on 15 July, a filament that had snaked its way down our star's northern hemisphere erupted, carving out a roughly 238,880-mile-long (384,400 kilometers) and 12,400-mile-deep (20,000 km) 'canyon of fire' on the Sun's surface and belching solar material right at us.
Solar filaments are huge arcs of electrified gas (or plasma) worming their way through the Sun's atmosphere according to the whims of the star's powerful magnetic field.
These giant magnetic tubes can hold huge masses of plasma above the Sun's surface, but they're also very unstable – and once they collapse, they can launch explosive jets of solar wind called coronal mass ejections (CMEs) barreling towards Earth.
"The long snake-like filament cartwheeled its way off the Sun in a stunning ballet," Tamitha Skov, a space weather physicist, wrote on Twitter following the eruption.
"The magnetic orientation of this Earth-directed solar storm is going to be tough to predict. G2-level (possibly G3) conditions may occur if the magnetic field of this storm is oriented southward!"
(G2 and G3 storms are ones that are considered moderate and strong, respectively.)
The CME ejected by the filament's collapse should slam into Earth today or tomorrow. On planets that have strong magnetic fields, like our own, our magnetic field absorbs the barrage of solar debris from CMEs, triggering powerful geomagnetic storms.
During these storms, Earth's magnetic field gets compressed slightly by the waves of highly energetic particles, which trickle down magnetic-field lines near the poles and agitate molecules in the atmosphere, releasing energy in the form of light to create colorful auroras, similar to the ones that make up the Northern Lights.
Thankfully, the storm coming from this filament is a weak one. Classified as a G1 solar storm, it has the potential to cause fluctuations in power grids and impact some satellite functions – including those for mobile devices and GPS systems, but not dramatically. It will also bring the aurora as far south as Michigan and Maine.
More extreme geomagnetic storms can disrupt our planet's magnetic field powerfully enough to send satellites tumbling to Earth, Live Science previously reported, and scientists have warned that extreme geomagnetic storms could even cripple the internet.
Erupting debris from CMEs usually takes around 15 to 18 hours to reach Earth, according to the National Oceanic and Atmospheric Administration's (NOAA) Space Weather Prediction Center, but it can, like this CME, move slower and take longer to arrive.
This storm comes as the Sun climbs into its most active phase of its roughly 11-year-long solar cycle. It is the second solar storm to have hit Earth in 24 hours.
Astronomers have known since 1775 that solar activity rises and falls in cycles, but recently, the Sun has been more active than expected, with nearly double the sunspot appearances predicted by NOAA.
The Sun's activity is projected to steadily climb for the next few years, reaching an overall maximum in 2025 before decreasing again.
A paper published 20 July in the journal Astronomy and Astrophysics proposed a new model for the Sun's activity by separately counting sunspots in each hemisphere – a method the paper's researchers argue could be used to make more accurate solar forecasts.
Scientists think the largest solar storm ever witnessed during contemporary history was the 1859 Carrington Event, which released roughly the same energy as 10 billion 1-megaton atomic bombs.
After slamming into Earth, the powerful stream of solar particles fried telegraph systems all over the world and caused auroras brighter than the light of the full moon to appear as far south as the Caribbean.
If a similar event were to happen today, scientists warn, it would cause trillions of dollars in damage and trigger widespread blackouts, much like the 1989 solar storm that released a billion-ton plume of plasma and caused a blackout across the entire Canadian province of Quebec, NASA reported.