Astronomers have spotted an aurora on the sun for the very first time. Here are the exciting details.
Aurora-like display on the sun
Scientists have discovered a spectacular display of crackling radio waves over the surface of the sun that resembles the Northern Lights on Earth.
The solar event occurred approximately 25,000 miles (40,000 kilometers) above a sunspot – a magnetically distorted dark patch on the surface of our star. Astronomers detected the bursts of radio waves over the course of a week.
Although scientists have found aurora-like radio signals from distant stars before, this is the first time they have observed a signal of this kind from our own sun. The findings were published on November 13 in the journal Nature Astronomy.
“This is quite unlike the typical, transient solar radio bursts typically lasting minutes or hours,” lead author Sijie Yu, an astronomer at New Jersey Institute of Technology’s Center for Solar-Terrestrial Research (NJIT-CSTR), said in a statement.
“It’s an exciting discovery that has the potential to alter our comprehension of stellar magnetic processes.”
Auroras on Earth occur when energetic solar debris travels through the atmosphere near the poles, where the protective magnetic field is weakest.
As the debris interacts with oxygen and nitrogen molecules, it causes them to release energy in the form of light, creating rippling curtains of color across the sky.
Solar debris is typically propelled away from the sun when magnetic fields around sunspots become twisted before suddenly snapping.
This release of energy results in bursts of radiation known as solar flares and explosive jets of solar material called coronal mass ejections (CMEs).
Researchers have discovered an aurora-like emission above a sunspot on the surface of our star by pointing a radio telescope at it.
They believe the emission is caused by electrons from solar flares being accelerated along the sunspot’s powerful magnetic field lines.
“However, unlike the Earth’s auroras, these sunspot aurora emissions occur at frequencies ranging from hundreds of thousands of kHz [kilohertz] to roughly 1 million kHz — a direct result of the sunspot’s magnetic field being thousands of times stronger than Earth’s,” Yu said. For comparison, a typical aurora on Earth emits light at frequencies between 100 to 500 kHz.