Directly under the Arctic Circle! Marianne's Arctic Xpress in Tromsø offers fjord, whale and wildlife tours by day, aurora tours by night. Book Now and get a 10% discount on combo day and night adventures. | | | POSSIBLE CME IMPACT: A minor coronal mass ejection (CME) that left the sun on Oct. 20th could reach Earth later today, Oct. 23rd, delivering a glancing blow to our planet's magnetic field. A high-speed solar wind stream (described below) is following close behind the CME. The combined effect of the CME+solar wind could spark G1- to G2-class geomagnetic storms on Oct. 24th and 25th. High-latitude sky watchers should be alert for auroras in the nights ahead. Free: Aurora Alerts. A HOLE IN THE SUN'S ATMOSPHERE--UPDATED: A large coronal hole is turning to face Earth, and it is spewing a complicated stream of solar wind toward our planet. This image from NASA's Solar Dynamics Observatory shows the outlines of the structure on Oct. 22nd: Coronal holes are places in the sun's atmosphere where the magnetic field opens up and allows solar wind to escape. Big holes like this one typically appear once or twice a month. According to NOAA computer models, the emerging stream of solar wind could reach Earth as early as Oct. 24th. Because the stream is broad, it will influence our planet for 2 to 3 days, possibly sparking polar geomagnetic storms and Arctic auroras for several nights in a row. Stay tuned for updates as the solar wind approaches. Realtime Aurora Photo Gallery SINUSOIDAL GROUND CURRENTS IN NORWAY: Last night in the Lofoten Islands of Norway, electrical currents began to flow through the ground, back and forth with a sinusoidal period of 74 seconds. Rob Stammes recorded the phenomenon at his geomagnetic observatory: "Just after midnight UTC and around 02.36 local time, my ground current instruments picked up these very stable pulsations," says Stammes. Currents in the ground are connected to events high overhead. Earth's magnetic field above the Lofoten Island was also swinging back and forth, inducing amperage in the soil beneath Stamme's observatory. These are natural ultra-low frequency oscillations known to researchers as "pulsations continuous" (Pc). The physics is familiar to anyone who has studied bells or resonant cavities. Earth's magnetic field carves out a cavity in the surrounding solar wind. Pressure fluctuations in the solar wind can excite wave modes in the cavity--usually in a noisy cacophany of many frequencies, but sometimes (like last night) with monochromatic purity. In a sense, Earth's magnetic field "rings like a bell," with slow tones that reach all the way down to the ground. References: #1, #2, #3. Realtime Space Weather Photo Gallery CRISS-CROSSED CLOUDS OVER MONO LAKE: Spaceweather.com reader James Phillips was driving past Mono Lake in central California yesterday when he saw something in the sky that made him pull over for a photo. Clouds above the lake were criss-crossed by dark lines: "It was visually striking," says Phillips. "Several people at a nearby gas station were staring up at the phenomenon." What caused it? "Airplanes," he says. Mono Lake is under a busy flight corridor leading from Los Angeles CA to Reno NV. Each plane makes a contrail, and each contrail cast its shadow on a layer of cirrus clouds below. "The dark lines are not 'furrows' in the clouds," says Phillips, "they are shadows. I saw one form as a plane flew overhead." Contrails and their shadows are notorious tricksters. Sometimes contrails look like they are beneath the clouds, casting their shadows up instead of down. Look for them whenever cirrus clouds fill the sky and planes are flying overhead. Realtime Space Weather Photo Gallery Realtime Airglow Photo Gallery Realtime Sprite Photo Gallery | Cosmic Rays in the Atmosphere | Updated: Sept. 29 2016 // Next Flight: Oct. 1, 2016 Sept. 20, 2016: Readers, thank you for your patience while we continue to develop this new section of Spaceweather.com. We've been working to streamline our data reduction, allowing us to post results from balloon flights much more rapidly, and we have developed a new data product, shown here: This plot displays radiation measurements not only in the stratosphere, but also at aviation altitudes. Dose rates are expessed as multiples of sea level. For instance, we see that boarding a plane that flies at 25,000 feet exposes passengers to dose rates ~10x higher than sea level. At 40,000 feet, the multiplier is closer to 50x. These measurements are made by our usual cosmic ray payload as it passes through aviation altitudes en route to the stratosphere over California. What is this all about? Approximately once a week, Spaceweather.com and the students of Earth to Sky Calculus fly space weather balloons to the stratosphere over California. These balloons are equipped with radiation sensors that detect cosmic rays, a surprisingly "down to Earth" form of space weather. Cosmic rays can seed clouds, trigger lightning, and penetrate commercial airplanes. Furthermore, there are studies ( #1, #2, #3, #4) linking cosmic rays with cardiac arrhythmias and sudden cardiac death in the general population. Our latest measurements show that cosmic rays are intensifying, with an increase of more than 12% since 2015: Why are cosmic rays intensifying? The main reason is the sun. Solar storm clouds such as coronal mass ejections (CMEs) sweep aside cosmic rays when they pass by Earth. During Solar Maximum, CMEs are abundant and cosmic rays are held at bay. Now, however, the solar cycle is swinging toward Solar Minimum, allowing cosmic rays to return. Another reason could be the weakening of Earth's magnetic field, which helps protect us from deep-space radiation. The radiation sensors onboard our helium balloons detect X-rays and gamma-rays in the energy range 10 keV to 20 MeV. These energies span the range of medical X-ray machines and airport security scanners. The data points in the graph above correspond to the peak of the Reneger-Pfotzer maximum, which lies about 67,000 feet above central California. When cosmic rays crash into Earth's atmosphere, they produce a spray of secondary particles that is most intense at the entrance to the stratosphere. Physicists Eric Reneger and Georg Pfotzer discovered the maximum using balloons in the 1930s and it is what we are measuring today. Every night, a network of NASA all-sky cameras scans the skies above the United States for meteoritic fireballs. Automated software maintained by NASA's Meteoroid Environment Office calculates their orbits, velocity, penetration depth in Earth's atmosphere and many other characteristics. Daily results are presented here on Spaceweather.com. On Oct. 23, 2016, the network reported 40 fireballs. (22 sporadics, 15 Orionids, 2 epsilon Geminids, 1 Southern Taurid) In this diagram of the inner solar system, all of the fireball orbits intersect at a single point--Earth. The orbits are color-coded by velocity, from slow (red) to fast (blue). [Larger image] [movies] Potentially Hazardous Asteroids ( PHAs) are space rocks larger than approximately 100m that can come closer to Earth than 0.05 AU. None of the known PHAs is on a collision course with our planet, although astronomers are finding new ones all the time. On October 23, 2016 there were 1736 potentially hazardous asteroids. Notes: LD means "Lunar Distance." 1 LD = 384,401 km, the distance between Earth and the Moon. 1 LD also equals 0.00256 AU. MAG is the visual magnitude of the asteroid on the date of closest approach. | The official U.S. government space weather bureau | | The first place to look for information about sundogs, pillars, rainbows and related phenomena. | | Researchers call it a "Hubble for the sun." SDO is the most advanced solar observatory ever. | | 3D views of the sun from NASA's Solar and Terrestrial Relations Observatory | | Realtime and archival images of the Sun from SOHO. | | from the NOAA Space Environment Center | | a proud supporter of science education and Spaceweather.com | | the underlying science of space weather | | Find homes for sale in Ocala, Orlando and Tampa with the #1 real estate company in Central Florida Local Realty Service | | Visit Need An Eitzah for all your questions and forum discussions on Jewish life. | | These links help Spaceweather.com stay online. Thank you to our supporters! | |