CHANCE OF STORMS TODAY: NOAA forecasters estimate a 65% chance of G1-class geomagnetic storms later today when a fast-moving stream of solar wind makes contact with Earth's magnetic field. Tomorrow could be even stormier. There is a 75% chance of G1-class storms with periods of moderate G2-class storming on Oct. 25th. High-latitude sky watchers should be alert for auroras. Free: Aurora Alerts.
NOISY AURORAS: On Oct. 23rd, the night sky above Tromsø, Norway, exploded in a twisted spray of green auroras. Tour guide Markus Varik knew something was happening without even looking up. "The electric wires were going bananas with crackling sounds," he explains. "We could literally hear the storm."
For centuries, Arctic sky watchers have reported hearing aurora sounds: claps, crackles, hissing, even "blaster fire." They are most often heard during intense geomagnetic activity. The underlying physics is still controversial, but the menagerie of sounds appears to be real.
"For me, it's not unusual to hear auroras, as I work with the Northern Lights tours on a regular basis," says Varik. "Typically, the volume waxes and wanes with the brightness of the aurora. I heard especially loud sounds during the major solar storm of March 17, 2015. It was so strong, it felt like it was coming from my bones!"
"The sounds I have heard are pretty similar to the ones [reported by Oliver Wright in Sweden]," he says. "The closest other natural sound I can think of is when you step on ice and it cracks. Or if there is a frozen part of the sea and the tide is going out, making it collapse a bit and releasing this specific sound."
"This week I will take an audio recorder out with me and try to capture some samples," says Varik. Stay tuned for that.
OPALITE CRYSTAL SPACE PENDANT: On Oct. 15, 2017, the students Earth to Sky Calculus launched a space weather balloon from the Sierra Nevada mountains of central California. Its mission: to measure cosmic rays at the top of Earth's atmosphere. The payload carried an array of X-ray/gamma-ray detectors, GPS trackers, temperature/pressure sensors and, for fundraising, opalite crystals:
With a soothing blue glow that matches the otherworldly color of Earth's upper atmosphere, these crystals ascended to an altitude of 32 km (105,000 feet) where the balloon exploded. The payload parachuted back to Earth, landing in the Eureka Valley on the outskirts of Death Valley National Park.
You can have one for $119.95. Each necklace comes with a unique gift card showing the pendant floating at the top of Earth's atmosphere. The interior of the card tells the story of the flight and confirms that this gift has been to the edge of space and back again.
Far Out Gifts: Earth to Sky Store
All proceeds support hands-on STEM education
ATMOSPHERIC CANYON ON THE SUN: A large hole has opened in the sun's atmosphere, cleaving the Earth-facing side of the sun with a gaseous canyon more than 700,000 km long. This image, based on data from NASA's Solar Dynamics Observatory, shows the jagged structure directly facing Earth on Oct. 22nd:
This is a coronal hole--a region where the sun's magnetic field peels back and allows solar wind to escape. The solar wind emerging from this hole is blowing faster than 600 km/s and is expected to reach Earth during the late hours of Oct. 24th. NOAA forecasters say there is a 65% chance of polar geomagnetic storms on Oct. 24th, increasing to 75% on Oct. 25th. Arctic auroras are in the offing. Free: Aurora Alerts.
Realtime Space Weather Photo Gallery
WANTED: TALES OF SPOOKY SPACE WEATHER: Have you ever been spooked by something you saw in the night sky? Maybe it was a ghoulish form in the aurora borealis, or the haunting glow of a rocket fuel dump--or something you couldn't figure out at all! In the spirit of Halloween, Spaceweather.com is reaching out to you, our readers, to share a spooky story about the night sky. Fill out this short survey, and your tale could end up on the front page of our web site as Halloween approaches. (Note: Image and audio files are accepted by the survey form.)