Could the SUN wipe out humanity? Superflares erupting from the star could destroy our atmosphere, astronomers warn

  • Researchers used observations of magnetic fields on the surface of stars
  • Magnetic fields on superflare stars are typically stronger than on our sun
  • This suggests that our sun is not capable of producing such superflares
  • However, superflares were found on stars with fields weaker than ours - and there may have even been a superflare in 775 AD

Earth is often struck by solar eruptions, but they tend to have little impact other than beautiful auroras seen around the planet's poles.

But if these bursts of energetic particles were to become powerful enough, they could devastate our planet, wipe out electricity and even destroy the atmosphere. 

That's the warning from a group of astronomers that recently discovered our sun is capable of producing the kind of 'superflares' seen on other stars.

Earth is often struck by solar eruptions with minimal impact, but if these bursts of energetic particles were powerful enough, they could devastate our planet. That's the stark warning from a group of astronomers that recently discovered our sun is capable of producing the kind of 'superflares' seen on other stars

Earth is often struck by solar eruptions with minimal impact, but if these bursts of energetic particles were powerful enough, they could devastate our planet. That's the stark warning from a group of astronomers that recently discovered our sun is capable of producing the kind of 'superflares' seen on other stars

Although the researchers said the chances of it happening is low, they added it's 'not impossible', and one described the findings as 'frightening.'

Solar flares occur when large magnetic fields on the surface of the sun collapse. When that happens, huge amounts of magnetic energy are released.  

When the sun pours out gigantic amounts of hot plasma during large solar eruptions, it can cause consequences on Earth. In particular, it can affect satellites and communication equipment. 

HAS OUR SUN EVER PRODUCED A SUPERFLARE?

Evidence from geological archives has shown the sun might have produced a small superflare in AD 775.

Here, tree rings show that anomalously large amounts of the radioactive isotope 14C were formed in the Earth's atmosphere. 

14C is formed when cosmic-ray particles from our galaxy, the Milky Way, or especially energetic protons from the sun, formed in connection with large solar eruptions, enter the Earth's atmosphere.

The studies from the Guo Shou Jing telescope support the notion that the event in AD 775 was indeed a small superflare.

But our sun's solar eruptions are nothing compared to the eruption we see on other stars - the so-called 'superflares'. 

Superflares have been a mystery since the Kepler mission discovered them in larger numbers four years ago, and astronomers have questioned whether they could be produced by our sun ever since.

They are typically considered solar eruptions between 10 and 100 times larger that the largest solar eruption observed during the space age. 

An international research team led by Christoffer Karoff from Aarhus University, Denmark used observations of magnetic fields on the surface of almost 100,000 stars to answer this questions. 

The team used a spectrum for every star of those available for this analysis. 

A spectrum shows the colours, or wavelengths, of the light from the stars. 

Here, certain short ultraviolet wavelengths can be used to measure the magnetic fields around the stars. 

These observations were made with the new Guo Shou Jing telescope in China.  

'The magnetic fields on the surface of stars with superflares are generally stronger than the magnetic fields on the surface of the sun,' explained Karoff.

An international research team led by Christoffer Karoff from Aarhus University, Denmark used observations of magnetic fields on the surface of almost 100,000 stars. These observations were made with the new Guo Shou Jing telescope in China (pictured)

An international research team led by Christoffer Karoff from Aarhus University, Denmark used observations of magnetic fields on the surface of almost 100,000 stars. These observations were made with the new Guo Shou Jing telescope in China (pictured)

The magnetic fields on the surface of stars with superflares were generally stronger than the magnetic fields on the surface of the sun. The range of stars with superflares is shown in red. Stars with the highest energies are in green, and the blue shaded region marks the sun's energy between solar cycle minima and maxima

The magnetic fields on the surface of stars with superflares were generally stronger than the magnetic fields on the surface of the sun. The range of stars with superflares is shown in red. Stars with the highest energies are in green, and the blue shaded region marks the sun's energy between solar cycle minima and maxima

SOLAR ERUPTIONS AND EARTH 

The sun is capable of producing monstrous eruptions that can break down radio communication and power supplies here on Earth. 

The largest observed eruption took place in September 1859, where gigantic amounts of hot plasma from our neighboring star struck the Earth.

On 1 September 1859, astronomers observed how one of the dark spots on the surface of the sun suddenly lit up and shone brilliantly over the solar surface. 

This phenomenon had never been observed before and nobody knew what was to come. On the morning of September 2, the first particles from, what we now know was an enormous eruption on the sun, reached the Earth.

The 1859 solar storm is also known as the 'Carrington Event'. 

Auroras associated with this event could be seen as far south as Cuba and Hawaii, telegraph system worldwide went haywire, and ice core records from Greenland indicate that the Earth's protective ozone layer was damaged by the energetic particles from the solar storm.

'This is exactly what we would expect, if superflares are formed in the same way as solar flares.'

This suggests that the magnetic field of our sun is too weak to produce such superflares, otherwise we would have witnessed them. 

However, out of all the stars with superflares analysed, around 10 per cent had a magnetic field with a strength similar to or weaker than the sun's magnetic field.

Therefore, even though it is unlikely, it is not impossible that the sun could produce a superflare, the researchers said.

'We certainly did not expect to find superflare stars with magnetic fields as week as the magnetic fields on the sun,' the continued.

'This opens the possibility that the sun could generate a superflare - a very frightening thought' added Karoff.

If an eruption of this size was to strike the Earth today, it would have devastating consequences. 

Not just for all electronic equipment on Earth, but also for our atmosphere and thus our planet's ability to support life. 

Plus, evidence from geological archives has shown the sun might have produced a small superflare in 775 AD. 

'One of the strengths of our study is that we can show how astronomical observations of superflares agree with Earth-based studies of radioactive isotopes in tree rings.' explained Karoff.

In this way, the observations from the Guo Shou Jing telescope can be used to evaluate how often a star with a magnetic field similar to the sun would experience a superflare. 

Around 10% of the stars analysed had a magnetic field with a strength similar to or weaker than our sun's. Therefore, even though it is unlikely,  it is not impossible  the sun could produce a superflare. Statistically speaking, it should experience a small superflare every millennium. Graph shows flare frequency

Around 10% of the stars analysed had a magnetic field with a strength similar to or weaker than our sun's. Therefore, even though it is unlikely,  it is not impossible the sun could produce a superflare. Statistically speaking, it should experience a small superflare every millennium. Graph shows flare frequency

The study shows, for example, that the sun, statistically speaking, should experience a small superflare every millennium.

This is in agreement with idea that the event in 775 AD and a similar event in 993 AD were indeed caused by small superflares on the sun. 

The findings are published in Nature Communications.