Why the northern and southern lights appear to be so active right now
By Katie Hunt, CNN
The breathtaking dancing shimmer of the aurora borealis and its counterpart in the southern hemisphere, aurora australis, dazzles those lucky enough to catch a glimpse of Earth’s greatest light show.
The northern and southern lights, usually confined to the Arctic and Antarctica, have generated awe and wonder for centuries and continue to do so.
In recent days, photographers and night sky watchers have been capturing the colorful display further south (or north if you’re in the southern hemisphere) than usual — places like the state of Colorado, the southeast of England and New South Wales. Pilots have circled their planes mid-flight to give their passengers a closer look at the phenomenon.
What causes auroras?
Auroras are caused by activity on the sun — particularly a type of solar storm called a coronal mass ejection, which emits electrified gas and particles into space. When these electrified particles reach magnetic field lines at the north and south poles, which usually takes around three days, they enter into Earth’s atmosphere.
Once there, the particles and energy interact with gases in the atmosphere, producing different colored light in the sky. Oxygen gives off green, the most commonly seen color, as well as red light, according to Aurora Watch at Lancaster University in the United Kingdom. Nitrogen glows blue and purple, according to NASA.
Clear weather can also help make the auroras more visible.
Researchers at NASA’s Solar Dynamics Observatory said they detected two M-class solar flares on Friday and Saturday that led to coronal mass ejections (CMEs), triggering the recent bout of elevated geomagnetic activity and producing the captivating auroras. The smallest solar flares are designated A-class, followed by B, C, M and X, the largest, according to NASA.
CMEs can also sometimes disrupt satellite operations and communication on Earth.
On Tuesday, another solar flare erupted only a shade below “X-class,” according to EarthSky, although there was no accompanying CME.
The latest uptick in geomagnetic activity has been driven by a “large and magnetically complex” sun spot region known as AR3234, according to the UK’s Met Office.
How frequent are auroras?
The recent geomagnetic wild ride is now expected to ease, meaning fewer opportunities for people to see the northern or southern lights in the coming days.
Over the next few years, the northern lights might appear further south more regularly, said Robert Massey, executive director at the Royal Astronomical Society.
The sun goes through an 11-year solar cycle where the flare activity level fluctuates. Cycle 25, the latest one, began in December 2019 with a solar minimum — a period when the sun is still active, but it’s quieter and has fewer sunspots.
We’re now approaching a solar maximum, expected to occur in July 2025, which will be a time when there are a large number of sunspots and increased solar activity.
Massey said the solar events that cause auroras will become more common as we head toward the solar maximum.
Other planets in the solar system also experience auroras.
Jupiter is bathed in spectacular color at its poles, although its powerful auroras are caused by a different mechanism that those on Earth, according to research published in 2021.
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Ashley Strickland and Megan Marples contributed to this report.
