Comet NEOWISE (C/2020 F3) with the Northern Lights and a STEVE arc aurora to the left, over the Waterton River at Waterton Lakes National Park, Alberta, in July 2020. Photo: Alan Dyer/VW PICS/Universal Images Group via Getty Images
Stargazers and space fans take note: More chances to spot the rare cosmic phenomenon known as STEVE are expected in the next few years.
The big picture: Because of an increase in solar activity, the elusive and hard-to-predict STEVE — a colorful light arc that is often purple or white and often seen with auroras — will be lighting up the sky, researchers say.
- STEVE and auroras appear most in March and September near the equinoxes. April is the third most popular month, according to a Washington Post analysis of data from NASA's Aurorasaurus.org project.
Recent STEVE sightings were triggered by a severe geomagnetic storm on March 23, and the phenomenon was photographed in South Dakota, Washington state, Idaho, Montana (twice) and in Scotland in the U.K., Space.com reports.
- The Post reported it was the strongest solar storm since 2017 with northern lights or auroras as far south as Virginia, North Carolina and Arizona.
What is STEVE?
STEVE is short for Strong Thermal Emission Velocity Enhancement and isn't an aurora but a "skyglow" created by heated and shining particles in the ionosphere, according to the journal Geophysical Research Letters.
Flashback: STEVE rose to prominence in 2018, when news of the new kind of skyglow with the funny name spread on the internet, Axios Space author Miriam Kramer explains.
- The unique glow was first noted by a sky-watchers' Facebook group, with one of the members, Chris Ratzlaff, naming it STEVE, according to NASA.
- It wasn't until later on that STEVE received its acronym.
STEVE and Northern Lights aurora viewing tips
STEVE and auroras are both hard to spot but watching space weather forecasts can help.
- Two popular forecasts are the National Oceanic and Atmospheric Administration’s Space Weather Prediction Center and the Geophysical Institute at the University of Alaska Fairbanks, which has aurora forecasts in one-hour, three-day and 27-day increments.
Aurora viewing depends on four factors, according to NOAA's space prediction center.
1. Geomagnetic activity: “If the geomagnetic field is active, then the aurora will be brighter and further from the poles. Geomagnetic activity is driven by solar activity and solar coronal holes and thus it waxes and wanes with time.”
2. Location: Go towards the magnetic poles.
- “The north magnetic pole is currently about 400 km (250 miles) from the geographic pole and is located in the islands of north east Canada,” the prediction center said. “Find a place where you can see to the north (or south if you are in the southern hemisphere).”
- Alaska is known for being one of the best places to view auroras along with Canada and Scandinavia because of the high northern latitudes, according to the institute.
- During rare and very large auroral events, auroras may be seen throughout the U.S. and Europe.
3. Darkness: It needs to be dark and you’ll need to get away from city lights.
The institute notes there is “always some aurora at some place on earth” but it might be faint and occur at very high latitudes. “Sunlight and clouds are the biggest obstacles to auroral observations.”
4. Timing: Between 10 pm and 2 am local time is usually the best time to spot auroras, the prediction center said.
- The best seasons for aurora watching are around the spring and fall equinoxes.
- The aurora viewing season in Fairbanks, Alaska is Aug. 21 to April 21, the institute said, suggesting a trip of at least three nights for better odds.
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