This relatively small October solar flare (the central bright flare observed by NASA’s Solar Dynamics Observatory) would be dwarfed by a super flare.
NASA/SDO
The Sun may produce very powerful bursts of radiation more often than we thought. According to surveys of Sun-like stars, they appear to occur as often as once a century, and may be accompanied by particle storms that can have devastating effects on Earth’s electronics. Since the last major solar storm to hit Earth was 165 years ago, we may be in line for another one soon, but it’s unclear how similar the sun is to these other stars.
Direct measurements of the sun’s activity only began in the middle of the 20th century. In 1859, our star created one very strong solar radiation, burst of light radiation. These are often associated with a subsequent coronal mass ejection (CME), a bubble of magnetized plasma particles that is ejected into space.
This flare was followed by a CME that hit the Earth and caused an intense geomagnetic storm, which was recorded by astronomers at the time, and is now known as the Carrington event. If it happened today, it could wipe out communication systems and power grids.
there it is also proof of much stronger storms on Earth long before the Carrington event. Assessments of radioactive forms of carbon in tree rings and ice cores suggest that the Earth has occasionally been bombarded with very high-energy particles over several days, but it is unclear whether these came from single, massive solar flares. smaller ones It is not certain whether the sun can produce such large flares and particle storms in a single explosion.
The frequency of these signs on Earth, as well as the superflares that astronomers have recorded on other stars, suggest that these giant explosions tend to occur every hundreds to thousands of years.
now, Ilya Usoskin At the University of Oulu in Finland and his colleagues, they studied 56,450 stars and found that sun-like stars produce superflares much more often than that.
“Superflares in Sun-like stars are much more frequent than we thought, roughly once every century or two,” says Usoskin. “If we believe that this projection to the sun is correct, then we expect a solar flare approximately every 100 to 200 years, and extreme solar storms, as we know them, occur approximately every 1500 to 2000 years. There is a disagreement.”
Usoskin and his colleagues measured the star’s brightness using the Kepler space telescope and detected a total of 2889 superflares in 2527 of the stars. The energies of these flares ranged from 100 to 10,000 times the size of the largest ever measured from the sun: the Carrington event.
We still don’t know whether such large flares also produce large particle events of the kind we have evidence for on Earth, says Usoskin, but current theories of the sun cannot explain such large flares. “That opens up the question of what we’re actually seeing,” he says.
“As an interstellar survey, it looks very impressive,” he says Mathew Owens at the University of Reading, UK. “It’s clear that they have new methods of detecting flares that are more sensitive.”
How much this tells us about the sun’s flaring activity is harder to discern, Owens says, partly because it’s difficult to accurately measure the rotation speed of other stars. “The devil is in the detail here,” he says.
“The rotation rate is important because it’s how a star generates a magnetic field, and the magnetic field is related to flaring activity,” says Owens.
Topics:
