Solar minimum is here - but even now strangely beautiful auroras are dancing around the poles. Deep inside the Arctic Circle, the expert guides of Aurora Holidays in Utsjoki, Finland, can help you chase them. Book now! | | |
INCREASING CHANCE OF GEOMAGNETIC STORMS: NOAA forecasters have boosted the odds of geomagnetic storms this week to 75% as a series of CMEs approaches Earth. The action begins on May 15th when the first CME is expected to arrive and could continue through May 17th as additional CMEs follow. Storms levels will almost certainly reach category G1 (minor) with isolated periods of G2 (moderate) storming as well. Auroras could cross the US-Canadian border in the nights ahead. Aurora Alerts: SMS Text.
BE ALERT FOR STEVE! There's more to geomagnetic storms than auroras. Sometimes a completely different phenomenon appears: STEVE. Steve Zhu (no relation) photographed the strange mauve ribbon arcing over Chilliwack BC on May 14th:
"It was so big I had to stitch together three shots to capture the whole thing," says Zhu. "I could see it even in bright moonlight."
STEVE is a hot (3000 degrees C) ribbon of ionized gas slicing through Earth's upper atmosphere some 300 km above the ground. It appears unpredictably during some, but not all, geomagnetic storms. Originally thought to be a type of aurora borealis, new research shows that it is not an aurora at all.
The soft purple color of STEVE may be caused by emissions from nitrogen, according to a new study just published in the Geophysical Research Letters. Its color and narrow ribbon-like structure distinguish it from regular auroras, which tend to be green and wide. Residents of Canada and northern-tier US states should look for STEVE this week after the CMEs hit. Aurora Alerts: SMS Text.
SURPRISE STORM SPARKS AURORAS IN THE USA: A surprise geomagnetic storm erupted during the early hours of May 14th when a crack opened in Earth's magnetic field. Solar wind poured through the gap, igniting auroras over northern-tier US states. Paul Nelson photographed the display from the shore of Lake Superior near Marquette, Michigan:
"The auroras were bright enough to see reflected in the still waters of Lake Superior," says Nelson. "The ISS made a visible pass during the best part of the show, right across and above the Northern Lights."
Auroras were also sighted in Ohio, the Dakotas, and Wyoming.
At its peak, the storm reached category G3--one of the strongest in years. NOAA analysts think the instigating crack may have been opened by an early-arriving CME. If you missed the show, good news: More CMEs are coming. Subscribers to the Space Weather Alert service can receive text messages when the storm clouds arrive. Stay tuned! Aurora Alerts: SMS Text.
Realtime Aurora Photo Gallery
COSMIC RAY BALLOON: When CMEs are coming, there's only one thing to do: Launch a cosmic ray balloon. Spaceweather.com and the students of Earth to Sky Calculus launched this one on May 13th:
The balloon carried an array of X-ray/gamma-ray sensors to the stratosphere more than 100,000 feet above Earth's surface. The students have been launching these balloons almost once a week for the past 4 years. They find that cosmic rays are increasing--a trend that might temporarily reverse this week.
CMEs sweep aside cosmic rays, causing atmospheric radiation levels to drop. The phenomenon is called a "Forbush Decrease," named after physicist Scott E. Forbush who first described it. The May 13th launch established a baseline by measuring levels before the CMEs arrived. During- and after-CME launches will take place in the days ahead. Stay tuned for results.
CRYSTAL MOON BALL IN THE STRATOSPHERE: On Star Wars Day ("May the 4th be with you"), the students of Earth to Sky Calculus launched an array of cosmic ray sensors to the stratosphere. They do this every week or so to monitor increasing levels of atmospheric radiation. This crystal Moon ball went along for the ride:
You can have it for $129.95. The students are selling these far-out balls to support their cosmic ray ballooning program.
Each one comes with an LED base that turns the laser-etched crystaline Moon a beautiful shade of purple, blue, green or yellow. It makes a great night light. Also included is a greeting card showing the crystal ball in flight and telling the story of its journey to the edge of space and back again.
Far Out Gifts: Earth to Sky Store
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Realtime Space Weather Photo Gallery
Free: Spaceweather.com Newsletter
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 May. 15, 2019, the network reported 7 fireballs.
(6 sporadics, 1 eta Aquariid)
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 May 15, 2019 there were 1983 potentially hazardous asteroids.
|
Recent & Upcoming Earth-asteroid encounters: Asteroid | Date(UT) | Miss Distance | Velocity (km/s) | Diameter (m) |
2019 JN3 | 2019-May-10 | 6.5 LD | 6.7 | 14 |
2019 JJ3 | 2019-May-10 | 2 LD | 9.7 | 11 |
2019 JV2 | 2019-May-11 | 18.1 LD | 16.2 | 92 |
2019 JL | 2019-May-12 | 14.3 LD | 9.2 | 21 |
2018 VX8 | 2019-May-12 | 6.2 LD | 15.5 | 118 |
2019 JO2 | 2019-May-12 | 3.7 LD | 10.8 | 26 |
2019 JM3 | 2019-May-12 | 10.8 LD | 20.3 | 36 |
2019 JR5 | 2019-May-13 | 11.1 LD | 25 | 41 |
2019 JK3 | 2019-May-13 | 3.2 LD | 10.7 | 16 |
2019 JW5 | 2019-May-13 | 2.3 LD | 11.5 | 12 |
2019 JO3 | 2019-May-14 | 18.5 LD | 10.8 | 47 |
2019 JN2 | 2019-May-15 | 7.1 LD | 6.8 | 26 |
2019 JN5 | 2019-May-16 | 4.4 LD | 13.1 | 28 |
2019 JG1 | 2019-May-17 | 5.6 LD | 8.1 | 17 |
2012 KT12 | 2019-May-17 | 4.2 LD | 4 | 20 |
2019 GT1 | 2019-May-17 | 6.1 LD | 3.9 | 36 |
2019 JR1 | 2019-May-18 | 16.2 LD | 10 | 44 |
2019 JB1 | 2019-May-20 | 16.8 LD | 26 | 233 |
2019 JL3 | 2019-May-20 | 2.5 LD | 8.8 | 37 |
2015 KQ18 | 2019-May-25 | 10.7 LD | 13.1 | 30 |
66391 | 2019-May-25 | 13.5 LD | 21.5 | 1780 |
2003 LH | 2019-May-28 | 15.6 LD | 7.4 | 32 |
2011 HP | 2019-May-30 | 12.3 LD | 8.4 | 135 |
2019 JX2 | 2019-Jun-06 | 13.8 LD | 7 | 44 |
2014 MF18 | 2019-Jun-06 | 8.8 LD | 3 | 22 |
441987 | 2019-Jun-24 | 7.7 LD | 12.6 | 178 |
2008 KV2 | 2019-Jun-27 | 17.8 LD | 11.4 | 195 |
2016 NN15 | 2019-Jun-28 | 9.6 LD | 8.4 | 16 |
2015 XC352 | 2019-Jul-01 | 11.9 LD | 4.1 | 26 |
2016 OF | 2019-Jul-07 | 12.8 LD | 8.5 | 85 |
2016 NO56 | 2019-Jul-07 | 3.4 LD | 12.2 | 26 |
2016 NJ33 | 2019-Jul-12 | 15 LD | 4.5 | 32 |
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. | Cosmic Rays in the Atmosphere |
SOMETHING NEW! We have developed a new predictive model of aviation radiation. It's called E-RAD--short for Empirical RADiation model. We are constantly flying radiation sensors onboard airplanes over the US and and around the world, so far collecting more than 22,000 gps-tagged radiation measurements. Using this unique dataset, we can predict the dosage on any flight over the USA with an error no worse than 15%.
E-RAD lets us do something new: Every day we monitor approximately 1400 flights criss-crossing the 10 busiest routes in the continental USA. Typically, this includes more than 80,000 passengers per day. E-RAD calculates the radiation exposure for every single flight.
The Hot Flights Table is a daily summary of these calculations. It shows the 5 charter flights with the highest dose rates; the 5 commercial flights with the highest dose rates; 5 commercial flights with near-average dose rates; and the 5 commercial flights with the lowest dose rates. Passengers typically experience dose rates that are 20 to 70 times higher than natural radiation at sea level.
To measure radiation on airplanes, we use the same sensors we fly to the stratosphere onboard Earth to Sky Calculus cosmic ray balloons: neutron bubble chambers and X-ray/gamma-ray Geiger tubes sensitive to energies between 10 keV and 20 MeV. These energies span the range of medical X-ray machines and airport security scanners.
Column definitions: (1) The flight number; (2) The maximum dose rate during the flight, expressed in units of natural radiation at sea level; (3) The maximum altitude of the plane in feet above sea level; (4) Departure city; (5) Arrival city; (6) Duration of the flight.
SPACE WEATHER BALLOON DATA: 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 18% since 2015:
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.
En route to the stratosphere, our sensors also pass through aviation altitudes:
In this plot, 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.
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.
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 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 |
| fun to read, but should be taken with a grain of salt! Forecasts looking ahead more than a few days are often wrong. |
| from the NOAA Space Environment Center |
| the underlying science of space weather |
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