Thursday, August 10, 2023

SPACE WEATHER
Powerful sun storm knocks out radio transmissions across North America

Tereza Pultarova
SPACE.COM
Tue, August 8, 2023 

An x flare bursting from the sun in August 2023.

A powerful solar flare disrupted radio and navigation signals across North America on Monday (Aug. 7) and prompted space weather forecasters to issue warnings because of energetic particles hitting Earth.

The flare, classified as an X1.5, was the 20th X flare — the most potent solar flare category — of the current 11-year solar cycle, which will reach its maximum next year.

Solar flares are energetic flashes of radiation that explode from magnetically dense, cool regions on the sun's surface known as sunspots. Traveling at the speed of light, the photons from these flares arrive at our planet in eight minutes. As the radiation from the flares interacts with particles in Earth's ionosphere, the region of the atmosphere at altitudes between 50 and 400 miles (80 and 650 kilometers), it supercharges them. These changes then affect radio and satellite signals that pass through this region.

Related: Sun blasts out highest-energy radiation ever recorded, raising questions for solar physics


According to solar physicist Keith Strong, the blackout caused by the Monday flare was a strong category 3 on the five-point scale developed by the U.S. National Oceanic and Atmospheric Administration (NOAA).

"The X1.5 Flare caused an R3 (strong) radio blackout event on the daylit side of the Earth (most of the US and Canada and the Pacific Ocean)," Strong said on X, formerly Twitter. "Frequencies below 5 Mhz were most affected and navigation signals degraded."

The flare burst out of the largest and most active sunspot group currently visible on the sun's disk, according to the U.K. space weather forecaster Met Office, and emerged only two days after a somewhat weaker X flare that occurred on Saturday (Aug. 5).

In addition to these two powerful flares, the sun also unleashed multiple moderate-class flares in recent days, three of which occurred in the past 24 hours.

The Met Office issued a warning for a mild solar radiation storm due to the presence of charged solar particles in Earth's atmosphere, a result of the lashing by those solar flares. In extreme cases, these charged particles may pose a radiation hazard to astronauts in space and passengers and crew on aircraft traveling over polar regions. They can also damage satellites in orbit. The current event, a mild category 1, should, however, be rather harmless.

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The Met Office predicts that further strong flares may occur while the large sunspot cluster remains visible on the face of the sun. That threatening region should, however, disappear behind the sun's edge within the next two days, giving space weather forecasters some respite.

In the meantime, however, these experts are bracing for the arrival of two coronal mass ejections (CME), huge clouds of magnetized gas that frequently escape from the sun together with solar flares. CMEs that hit Earth can cause a different type of phenomenon, known as a geomagnetic storm, as they interact with our planet's magnetic field.

Geomagnetic storms produce beautiful aurora displays but can also cause problems to satellite operators as they make Earth's atmosphere swell. In the most severe cases, geomagnetic storms can knock out power grids and telecommunication networks. The upcoming geomagnetic storm could reach a strong G3 level, according to Spaceweather.com.


Earth hit by powerful ‘X-1’ solar flare, after fears of ‘cannibal’ blast


Andrew Griffin
Wed, August 9, 2023 

NASA’s Solar Dynamics Observatory captured this image of a solar flare – as seen in the bright flash on the top right – on Oct. 2, 2022. The image shows a subset of extreme ultraviolet light that highlights the extremely hot material in flares and which is colorized in orange 
(NASA/SDO)

The Earth narrowly avoided being hit by a “cannibal” solar flare – but has been lashed by powerful enough blasts to disrupt communications.

In recent days, space weather forecasters had warned that the Earth could be hit by a range of powerful flares that have been ejected from the Sun. Particular warnings focused on the “cannibal” flare, which was forecast to potentially glance Earth.

“Cannibal” solar flares are formed when a later blast catches up with one that was ejected earlier, and consumes it. The energy of the two is combined, which can make them far more powerful than flares that are released on their own.

The latest cannibal flare appears to have missed Earth, however. Forecasts had suggested that it was only expected to glance the planet, and so a miss was perhaps likely.

The Earth was struck by an X-class flare, however. That is the most potent category of solar flares, and can cause considerable disruption on Earth.

This time around, space weather experts warned that the blast was enough to disrupt radio and navigation signals in North America. It was measured as an R3 blackout – on a scale that runs from 1 to 5 – which meant that areas in the US and Canada as well as on the Pacific Ocean were at risk of having radio signals and navigation disrupted.

The Sun moves through a cycle of activity every 11 years, during which it releases more and less “coronal mass ejections” or CMEs, and it is currently in a particularly busy part of that cycle. Those CMEs can bring energetic flares that hit Earth – and could one day cause considerable problems on the planet, disrupting energy grids and other important infrastructure.

The latest flare was measured at X1.5 and is the 20th such X flare to have hit the Earth in its current period. It came out of a particularly active part of the Sun, and followed other, weaker flares, the UK’s Met Office said.

Nonetheless, experts said the “minor ongoing solar radiation storm” was “waning” and that it did not expect significant disruption in the coming days.

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