Rare 'superflares' from Sun could disrupt Earth's communications

Milky Way Galaxy

An Incredibly Powerful White-Light Superflare Erupted from a Small, Faint Star

"But there is some possibility that we could experience such an event in the next 100 years or so".

A superflare is a massive burst of charged particles, solar energy and cosmic radiation from the surface of a star. New research shows that such eruptions can occur on stars as old and as inactive as our sun.

The solar flares have the potential to wipe out entire satellite networks and disrupt power grids around the globe.

It was previously thought that older stars like our Sun - a healthy 4.6 billion years old - didn't really have the power to eject superflares, however a group of eggheads led by the University of Colorado Boulder in the United States this week showed this isn't the case.

"It is unbelievable that such a puny star can produce such a powerful explosion", co-author Peter Wheatley, an astronomy and astrophysics professor at the University of Warwick and leader of the NGTS, said in the statement. Superflares that are of this scale are incredibly rare, and they can occur every few thousand years.

Before now, scientists had witnessed Sun-like stars - meaning G-type main-sequence stars - produce superflares, although we still can't fully explain how these high-energy events are unleashed, partially due to a lack of analysis.

"Our study shows that superflares are rare events", said Notsu, a researcher in CU Boulder's Laboratory for Atmospheric and Space Physics.

To investigate, Dr Notsu and his colleagues from Japan, the United States and the Netherlands studied superflares detected from 43 Sun-like stars using data from the European Space Agency's Gaia spacecraft and New Mexico's Apache Point Observatory.

Whilst a superflare would likely have a devastating effect on the inhabitants of planet Earth, it could be instrumental to the emergence of life on planets orbiting cold L dwarf stars.

It was long thought that these superflares only took place on young and active stars and that our sun-which is much older-would not be capable of producing them. They noticed that, at times, the light from some distant stars, hundreds of light-years away, would rapidly get brighter for a relatively short period of time.

Notsu explained that normal-sized flares are common on the Sun.

The confirmation that slowly rotating, Sun-like stars can still throw out powerful superflares is surely intriguing, but it's also a bit nerve-wracking.

"Young stars have superflares once every week or so", said the study's lead author, Yuta Notsu of the University of Colorado Boulder, in a press release.

"But we didn't know if such large flares occur on the modern Sun with very low frequency".

To understand more, Notsu's team ran new spectroscopic observations with Kepler data, also utilising data from the European Space Agency's Gaia spacecraft and the Apache Point Observatory in New Mexico.

"We need more studies to clarify the properties of superflare stars on Sun-like stars and to answer the important question, 'Can our Sun have superflares?'" the team writes.

The bottom line: age matters.

Older stars like our Sun do so "once every few thousand years on average". But he said that it's a matter of when, not if.

Dr Notsu hopes that the warning might give humanity time to prepare by developing shielding to protect electronics on the ground and in orbit from these bursts of stellar radiation.

"If a superflare occurred 1,000 years ago, it was probably no big problem", said Notsu. "People may have seen a large aurora", Notsu said.

"Now, its a much bigger problem because of our electronics".

Co-authors on the recent study include researchers from Kyoto University, the National Astronomical Observatory of Japan, University of Hyogo, University of Washington and Leiden University.

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