 | | | Switch to: Europe, USA, New Zealand, Antarctica Credit: NOAA/Ovation  Planetary K-index
Now: Kp= 3.67 quiet
24-hr max: Kp= 3.67 quiet
explanation | more data
Interplanetary Mag. Field
Btotal: 9.27 nT
Bz: 3.62 nT north
more data: ACE, DSCOVR
Updated: Today at 1147 UT Coronal Holes: 21 Dec 24 
Solar wind flowing from this minor coronal hole should reach Earth on Dec. 23-24. It is not big enough to cause a geomagnetic storm. Credit: NOAA/GOES-16 | more data  Polar Stratospheric Clouds
Colorful Type II polar stratospheric clouds (PSC) form when the temperature in the stratosphere drops to a staggeringly low -85C. NASA's MERRA-2 climate model predicts when the air up there is cold enough: 
On Dec. 21, 2024, the Arctic stratosphere is cold enough for Type I polar stratospheric clouds, but a few degrees too warm for Type II clouds. | more data. Noctilucent Clouds
The southern season for noctilucent clouds (NLCs) is underway!. The first clouds were detected over Antarctica on Nov. 19, 2024. Here is the current NLC map from the NOAA 21 satellite.
Updated: Dec. 18, 2024
An instrument onboard NOAA 21 (OMPS LP) is able to detect NLCs (also known as "polar mesospheric clouds" or PMCs). In the daily map, above, each dot is a detected cloud. As the season progresses, these dots will multiply in number and shift in hue from blue to red as the brightness of the clouds intensifies.
SPACE WEATHER
NOAA Forecasts | | Updated at: 2024 Dec 21 2200 UTC FLARE | 0-24 hr | 24-48 hr | CLASS M | 60 % | 60 % | CLASS X | 10 % | 10 % | Geomagnetic Storms:
Probabilities for significant disturbances in Earth's magnetic field are given for three activity levels: active, minor storm, severe storm Updated at: 2024 Dec 21 2200 UTC Mid-latitudes | 0-24 hr | 24-48 hr | ACTIVE | 10 % | 15 % | MINOR | 05 % | 05 % | SEVERE | 01 % | 01 % | High latitudes | 0-24 hr | 24-48 hr | ACTIVE | 15 % | 15 % | MINOR | 20 % | 25 % | SEVERE | 15 % | 25 % | | | |  | | | | | | | | | | | This is an AI Free Zone! Text created by Large Language Models is spreading rapidly across the Internet. It's well-written, but frequently inaccurate. If you find a mistake on Spaceweather.com, rest assured it was made by a real human being. | | | BIG SUNSPOT ALERT: A large and complicated group of sunspots has just emerged over the sun's southeastern limb. The group includes at least 15 dark cores and sprawls across more than 250,000 km of the sun's surface. Amateur astronomers, point your solar telescopes here. Solar flare alerts: SMS Text MERCURY'S TAIL HAS RETURNED: Space weather affects some planets more than others. It's really hard on Mercury. The solar wind scours Mercury's rocky surface at point-blank range, creating a "sodium tail" occasionally visible from Earth. David Marshall of Christ Church, Barbados, saw it on Dec. 20th: 
"It's back! Mercury's sodium ion tail is approximately 1 degree long in this image and is expected to become more prominent over the next couple of days," says Marshall. First predicted in the 1980s, Mercury’s tail was discovered in 2001. It is a yellow-orange tail of sodium-rich gas more than 24 million kilometers long. Mercury's tail brightens and dims as it orbits the sun. The predictable pattern is shown in this movie from NASA’s MESSENGER spacecraft, which spent years observing Mercury’s tail from close range: For reasons having to do with the Doppler shift of sodium absorption lines in the solar spectrum, Mercury’s tail is most luminous when the planet is ±16 days from perihelion (closest approach to the sun). The most recent perihelion was Dec. 7th. This means the tail will reach peak brightness on Dec. 23rd. Astronomers who wish to photograph the plume must wake up before dawn. Mercury is currently a bright "morning star" (magnitude –0.3) low in the southeast about 60 to 45 minutes before sunrise. Observing tip: A 589 nanometer filter tuned to the yellow glow of sodium greatly enhances the visibility of Mercury's tail. Realtime Space Weather Photo Gallery
Free: Spaceweather.com Newsletter CHRISTMAS GIFTS FROM THE EDGE OF SPACE: Christmas is coming. Are you looking for a far-out gift? Check out the Earth to Sky Store. It's filled with unique items that have flown to the edge of space onboard cosmic ray research balloons.
Carried aloft by giant helium balloons, these unique gifts have flown above 99.7% of Earth's atmosphere, experiencing space-like blasts of cosmic rays, extreme cold, and a wild ride parachuting back to Earth after the balloon explodes. Even Amazon doesn't carry items this far out. Don't forget to enter coupon code "BLACKCAT" at checkout for a 10% holiday discount. Far Out Gifts: Earth to Sky Store
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Realtime Comet Photo Gallery
Free: Spaceweather.com Newsletter
Realtime Aurora 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 Dec 19, 2024, the network reported 16 fireballs.
(13 sporadics, 3 December Leonis Minorids)  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 December 21, 2024 there were 2349 potentially hazardous asteroids.
 | Recent & Upcoming Earth-asteroid encounters: | Asteroid | Date(UT) | Miss Distance | Velocity (km/s) | Diameter (m) | | 2024 XY5 | 2024-Dec-16 | 9.1 LD | 4.8 | 23 | | 2024 XB6 | 2024-Dec-16 | 17.5 LD | 6.6 | 18 | | 2024 YN | 2024-Dec-16 | 2.7 LD | 19.3 | 12 | | 2024 XV6 | 2024-Dec-16 | 17.5 LD | 10.7 | 11 | | 2024 XE16 | 2024-Dec-16 | 17.7 LD | 3.7 | 47 | | 2024 VE7 | 2024-Dec-16 | 7.3 LD | 8 | 45 | | 2024 YL | 2024-Dec-17 | 2.2 LD | 3.3 | 5 | | 2022 YO1 | 2024-Dec-17 | 2 LD | 14.3 | 4 | | 2024 XR6 | 2024-Dec-17 | 15.3 LD | 5.6 | 16 | | 2024 XC17 | 2024-Dec-17 | 8.1 LD | 4.8 | 12 | | 2024 XS3 | 2024-Dec-18 | 8.7 LD | 10.5 | 27 | | 2024 YM | 2024-Dec-19 | 0.6 LD | 10.3 | 12 | | 2024 YA | 2024-Dec-19 | 3.7 LD | 5.3 | 16 | | 2020 XY4 | 2024-Dec-20 | 12.7 LD | 8.8 | 14 | | 2024 YD | 2024-Dec-20 | 1.2 LD | 10.6 | 13 | | 2024 XN15 | 2024-Dec-21 | 9.9 LD | 9.7 | 19 | | 2024 XQ4 | 2024-Dec-21 | 2.8 LD | 13.2 | 16 | | 2024 YC | 2024-Dec-22 | 1.6 LD | 6.4 | 12 | | 2024 XN1 | 2024-Dec-24 | 18.8 LD | 6.6 | 39 | | 2024 YH | 2024-Dec-26 | 9.6 LD | 10.4 | 30 | | 2017 YD2 | 2024-Dec-27 | 18 LD | 9.9 | 6 | | 2024 AV2 | 2024-Dec-31 | 6.7 LD | 7.8 | 17 | | 2024 XP10 | 2025-Jan-02 | 19.8 LD | 8.4 | 39 | | 2021 AO4 | 2025-Jan-04 | 6.9 LD | 15.1 | 11 | | 2020 BC6 | 2025-Jan-05 | 9.6 LD | 22.2 | 248 | | 2024 BM1 | 2025-Jan-08 | 11.5 LD | 9.1 | 22 | | 2024 PT5 | 2025-Jan-09 | 4.7 LD | 1 | 12 | | 2023 OS3 | 2025-Jan-09 | 19.9 LD | 3.1 | 10 | | 2012 UK171 | 2025-Jan-11 | 10.7 LD | 6.4 | 46 | | 2023 OS | 2025-Jan-15 | 16.6 LD | 10.9 | 48 | | 2022 CE2 | 2025-Jan-16 | 11.1 LD | 13.3 | 120 | | 2022 OB5 | 2025-Jan-18 | 8.9 LD | 1.4 | 6 | | 2024 WY70 | 2025-Jan-18 | 16.5 LD | 10.2 | 261 | | 2022 BX6 | 2025-Jan-28 | 19.7 LD | 14.3 | 24 | | 2015 DJ155 | 2025-Jan-31 | 18.6 LD | 9.2 | 56 | | 2022 AV4 | 2025-Feb-03 | 16.8 LD | 3.4 | 25 | | 2018 RE3 | 2025-Feb-03 | 15.5 LD | 11.1 | 12 | | 2002 CC14 | 2025-Feb-04 | 8.4 LD | 12.7 | 39 | | 2016 CO248 | 2025-Feb-07 | 13.5 LD | 5.9 | 11 | | 2020 GZ2 | 2025-Feb-07 | 17.7 LD | 8.9 | 9 | | 2022 PK1 | 2025-Feb-07 | 15 LD | 11 | 33 | | 2012 PB20 | 2025-Feb-09 | 3.5 LD | 4.3 | 37 | | 2004 XG | 2025-Feb-16 | 15.6 LD | 9.1 | 54 | | 2024 UD26 | 2025-Feb-16 | 16.8 LD | 9.3 | 250 | | 2014 CE13 | 2025-Feb-18 | 15.2 LD | 18.4 | 55 | Notes: LD means "Lunar Distance." 1 LD = 384,401 km, the distance between Earth and the Moon. 1 LD also equals 0.00256 AU. | | Cosmic Rays in the Atmosphere | SPACE WEATHER BALLOON DATA: Almost 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 sensors that detect secondary cosmic rays, a form of radiation from space that can penetrate all the way down to Earth's surface. Our monitoring program has been underway without interruption for 10 years, resulting in a unique dataset of in situ atmospheric measurements. Latest results (Nov. 2024): Atmospheric radiation is decreasing in 2024. Our latest measurements in November registered a 10-year low: 
What's going on? Ironically, the radiation drop is caused by increasing solar activity. Solar Cycle 25 has roared to life faster than forecasters expected. The sun's strengthening and increasingly tangled magnetic field repels cosmic rays from deep space. In addition, solar coronal mass ejections (CMEs) sweep aside cosmic rays, causing sharp reductions called "Forbush Decreases." The two effects blend together to bring daily radiation levels down. .Who cares? Cosmic rays are a surprisingly "down to Earth" form of space weather. They can alter the chemistry of the atmosphere, trigger lightning, and penetrate commercial airplanes. According to a study from the Harvard T.H. Chan school of public health, crews of aircraft have higher rates of cancer than the general population. The researchers listed cosmic rays, irregular sleep habits, and chemical contaminants as leading risk factors. A number of controversial studies (#1, #2, #3, #4) go even further, linking cosmic rays with cardiac arrhythmias and sudden cardiac death. Technical notes: 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. Data points in the graph labeled "Stratospheric Radiation" correspond to the peak of the Regener-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 Regener and Georg Pfotzer discovered the maximum using balloons in the 1930s and it is what we are measuring today. | | 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. | | | information about sunspots based on the latest NOAA/USAF Active Region Summary | | | current counts of failed and deployed Starlink satellites from Jonathan's Space Page. See also, all satellite statistics. | | | Authoritative predictions of space junk and satellite re-entries | | | 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 |  | Got a chipped or cracked windshield that prevents you from seeing space weather events while driving? Get windshield replacement from SR Windows & Glass with free mobile auto glass service anywhere in the Phoenix area. | | BestCSGOGambling is the best site for everything related to CSGO gambling on the web | | | These links help Spaceweather.com stay online. Thank you to our supporters! | | | | | | | | |  | | |  | ©2021 Spaceweather.com. All rights reserved. This site is penned daily by Dr. Tony Phillips. | |
