Solar flares, powerful bursts of radiation from the sun, often precede preflares, scientists say. The finding could lead to better predictions of solar storms, which can disrupt power grids and communications systems on Earth.
The scientists made the discovery after digging through years of data from NASA’s Solar Dynamics Observatory (SDO), a satellite that has been observing the sun since 2010. Since the 1970s and 80s, researchers have observed these pre-glacial flashes, instruments such as ground-based observatories were used, so there was a lot of anecdotal evidence that the flashes and flares were related, KD Leka (opens in a new tab), senior research scientist at Northwest Research Associates (NWRA) in Boulder, Colorado, told Live Science. But those researchers didn’t have instruments like SDO, which is constantly watching and recording the sun’s activity from space.
“Images of [the sun] They are certainly helping scientists and forecasters understand when an active region is likely to be capable of a productive flare,” said Leka.
In a new series of papers published in The Astrophysical Journal (opens in a new tab), Leka and her team combed nearly a decade of SDO data, zooming in on active regions of the sun called sunspots. These dark regions are places where the sun’s magnetic field is particularly active due to constraints deeper within the star. The contortions of the sun’s magnetic field create twist and tension. And when those magnetic field lines snap back into their original form, a massive burst of energy erupts from the surface.
These explosions can manifest as a solar flare or a coronary mass ejection (CME). Solar flares are intense bursts of X-rays and energy that radiate in all directions. The electromagnetic energy moves at the speed of light and can reach the Earth within 8 minutes. In contrast, CMEs are bursts of highly charged particles that explode in a specific direction. They move more slowly, at 155 to 1,900 miles per second (250 to 3,000 kilometers per second); it can take several days for a CME to sweep over the Earth.
Both types of explosion can damage power systems and telecommunications on Earth, but are usually harmless to people and other living things.
In the thousands of terabytes of data from SDO, Leka and her team found that solar flares are often associated with a moment of brightness, like when you hit a match and it goes away before lighting up. These sparks occurred up to one day before flares erupted from the same region of the sun, the authors found.
While the results are exciting for our understanding of solar physics, they don’t mean scientists can now predict solar flares, Leka said. Think of it like predicting a volcanic eruption – earthquakes near an active volcano tell scientists that underground magma is moving and that an eruption could result. So scientists monitor earthquakes and tweak models to predict when an eruption might occur. But no single earthquake is a predictor of a volcanic eruption.
“Down the road, combining all this information from the surface up through the corona [the sun’s outer atmosphere] It should allow forecasters to make better predictions about when and where solar flares will occur,” co-authored study Bishop Karin (opens in a new tab)research scientist at NDA, said in a statement (opens in a new tab).
So far, the research has sparked new questions for Leka, such as how the dynamics of the sun’s magnetic field is linked to processes occurring deep inside the sun and how to combine data from those two regions to help scientists predict solar eruptions .