The sun has emitted two huge solar flares - one of which was the biggest in more than a decade. While solar flares and winds don’t really pose a direct risk to human health, they could bring down communications.
Image: NASA
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The two bursts of radiation from the sun were so intense that high-frequency blackouts were experienced on Earth, lasting for about an hour.
Both were X-class flares – the most intense classification of coronal ejection – with the second being the biggest observed since 2006.
NASA's Solar Dynamics Observatory, which is constantly looking at the sun, captured images of both events.
The largest X-class flares are by far the largest explosions in the solar system, with loops of material tens of times the size of Earth being spat from the solar surface. They're caused when magnetic fields – which guide the motion of the sun's plasma – cross over each other and reconnect.
At their largest, such events can produce as much energy as a billion hydrogen bombs.
Effect on radio, GPS signals
While harmful radiation from such flares cannot pass through Earth's atmosphere to harm humans on the ground, they can disturb the atmosphere where GPS and communications signals travel.
The initial radiation from the solar flare would have created the radio disturbances experienced on Wednesday.
Our sun — A gigantic fireball
A probe called the Solar Orbiter was launched in February 2020. It's so far traveled halfway to the sun and is sending back fantastic images of our star — without which, life on Earth would be impossible.
The probe took these excellent pictures of our sun from 77 million kilometers away. Small solar flares have never before been so clearly visible. As it gets closer to the sun, the Solar Orbiter will specifically investigate these eruptions. It will also research how solar storms — which can cause problems for us on Earth — emerge.
The sun is constantly sizzling, boiling, and erupting. The eruptions are usually small, but sometimes they can be huge. During larger solar storms, billions of tons of electromagnetically charged material are hurled into space and toward the earth. This can have consequences for us. Those eruptions can lead to power cuts or the collapse of mobile phone networks.
Our sun had already been shining for billions of years before mankind even existed. Together with the planets of our solar system, the sun developed from a gas cloud 4.6 billion years ago. And it will probably continue shining for another five billion years, until its energy reserves run out.
Image: Reuters/Y. Behrakis
A big idol for energy researchers
The sun is basically a huge nuclear fusion reactor. At its core, pressure and temperature are so high that hydrogen atoms merge together to form helium atoms. This process releases huge amounts of energy. One thimble of sun material generates as much energy as burning thousand metric tons of coal does.
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100 times bigger than Earth
Seen from Earth, the sun doesn't seem big - it is just a bright spot in the sky. But it does have a radius of about 700,000 kilometres (435,000 miles). Its core is 15 million degree Celsius (27 million degree Fahrenheit). Temperatures on the sun's surface still reach 5500 degree Celsius (10,000 degree Fahrenheit).
Image: picture-alliance/dpa/F. Rumpenhorst
One in a billion
All stars in our universe glow because they generate energy deep down inside. Our sun is just like other billlions of stars scattered across the universe. In comparison with other stars, our sun is of medium size. Some stars are a hundred times bigger, others are just a tenth of the sun's size.
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Restless on the outside
The sun's surface is seething away. Hot and brightly glowing material ascends from the sun's inside, cools and sinks down again, appearing much darker. Our sun is the only star in the universe so close to Earth that astronomers can observe in such detail.
Image: Getty Images/Q. Rooney
Amazing sunspots
Sometimes big dark spots appear on the sun's surface staying for about a month. Even before the birth of Christ, humans already knew of those spots, and Galileo Galilei later recorded their appearance in writing. But for a long time people were mystified where those spots came from. Now we know the answer: they're areas with a particularly strong magnetic field.
Image: picture-alliance/ dpa
Dangerous storms
When the sun is very active, geomagnetic storms develop. It's when the sun catapults a particularly high number of charged particles into space. Those particles can hit and destroy satellites. They might also disturb electric power substations on Earth and even lead to power breakdowns.
Image: dapd
When the sky glows
This is another, much more beautiful effect of geomagnetic storms: an aurora, also called polar light. It occurs when charged particles of the sun hit the Earth's atmosphere. The frequency of how often we may enjoy this spectacle depends on the solar cycle. Every eleven years the sun is particularly active - that's when many geomagnetic storms and auroras can be observed.
Image: dapd
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The giant clouds of charged particles thrown out by the sun – known as a coronal mass ejection – could result in a radio blackout later, possibly on Thursday or Friday.
On the way here?
When directed at Earth, such flares create radiation storms that affect satellites and communications systems, even affecting technologies on the ground.
On the plus side, it might mean there'll be a chance for sky watchers in higher latitudes to see the aurora borealis, or its southern counterpart the aurora australis.
At present, scientists are looking at date from sun-watching satellites to see if the clouds are heading this way.
The first flare was measured at X2.2, with the second at X9.3. The number indicates the intensity of the burst.
The biggest solar flare in modern times was in 2003 and it was off the charts, being recorded at X28.
