Note: On Nov. 26, 2024, a flood at Stanford University damaged a number of important SDO data servers. Repairs will not be completed until 2025. As a result, for the foreseeable future, Daily Sun images will be coming from readers of Spaceweather.com. Thank you, citizen scientists!
Spotless Days Current Stretch: 0 days 2024 total: 0 days (0%) 2023 total: 0 days (0%) 2022 total: 1 day (<1%) 2021 total: 64 days (18%) 2020 total: 208 days (57%) 2019 total: 281 days (77%) 2018 total: 221 days (61%) 2017 total: 104 days (28%) 2016 total: 32 days (9%) 2015 total: 0 days (0%) 2014 total: 1 day (<1%) 2013 total: 0 days (0%) 2012 total: 0 days (0%) 2011 total: 2 days (<1%) 2010 total: 51 days (14%) 2009 total: 260 days (71%) 2008 total: 268 days (73%) 2007 total: 152 days (42%) 2006 total: 70 days (19%) Updated 18 Dec 2024
Thermosphere Climate Index today: 25.42x1010W Warm Max: 49.4x1010 W Hot (10/1957) Min: 2.05x1010 W Cold (02/2009) explanation | more data:gfx, txt Updated 18 Dec 2024
Cosmic RaysSolar Cycle 25 is intensifying, and this is reflected in the number of cosmic rays entering Earth's atmosphere. Neutron counts from the University of Oulu's Sodankyla Geophysical Observatory show that cosmic rays reaching Earth are slowly declining--a result of the yin-yang relationship between the solar cycle and cosmic rays. Oulu Neutron Counts Percentages of the Space Age average: today: -7.9% Low 48-hr change: -1.3% Max: +11.7% Very High (12/2009) Min: -32.1% Very Low (06/1991) explanation |more data Updated 18 Dec 2024 @ 0700 UT
Planetary K-index Now: Kp= 4.00 unsettled 24-hr max: Kp= 4.00 unsettled explanation | more data
Interplanetary Mag. Field Btotal: 6.32 nT Bz: -4.21 nT south more data: ACE, DSCOVR Updated: Today at 1147 UT
Coronal Holes: 18 Dec 24
There are no coronal holes on the Earthside of the sun. 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. 18, 2024, the Arctic stratosphere is cold enough for Type II polar stratospheric 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. 16, 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 18 2200 UTC
FLARE
0-24 hr
24-48 hr
CLASS M
40 %
45 %
CLASS X
05 %
05 %
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 18 2200 UTC
Mid-latitudes
0-24 hr
24-48 hr
ACTIVE
10 %
10 %
MINOR
05 %
05 %
SEVERE
01 %
01 %
High latitudes
0-24 hr
24-48 hr
ACTIVE
15 %
15 %
MINOR
20 %
20 %
SEVERE
15 %
15 %
Wednesday, Dec. 18, 2024
What's up in space
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.
ANOTHER FARSIDE EXPLOSION: Another magnificent halo CME left the farside of the sun on Dec. 17th. Watch the movie. This is fourth farside CME of the past 10 days, signaling a very active sunspot hidden from view. The sun's rotation will turn the active region toward Earth next week. Solar flare alerts:SMS Text
CHINA'S NEW MEGACONSTELLATION: Elon Musk has competition. Its name is "China." This past Monday, Dec. 16th, the China Satellite Network Group Co., Ltd., launched the first group of satellites for China's new Guowang megaconstellation. Daniel Parrott watched them deploying to orbit over Oklahoma:
"I was able to capture images of the deployment and counted 10 spacecraft," says Parrott.
Guowang is a Chinese initiative to compete with Starlink. Officials say that almost 13,000 satellites are planned for the network, with at least half launching before 2032. The role of Starlink in the Ukraine war caught the attention of Chinese military analysts, and they are determined to control their own satellite network to avoid dependence on foreign powers.
This is actually China's second megaconstellation of 2024. On Aug. 6th, China launched the first 18 satellites of its new Thousand Sails network, with subsequent launches boosting the total to 54. For comparison, Starlink currently has about 7,000 satellites, so China still has a long way to go.
Liftoff of the Long March 5B carrying the first group of Guowang satellites. Credit: Ourspace
Scientists have raised many concerns about Starlink including light-pollution of the night sky, a potentially hazardous traffic jam in low-Earth orbit, metallic contamination of the stratosphere, and even ozone depletion. Guowang and Thousand Sails will only multiply those concerns. It's a brand new Space Race with many uncharted hazards ahead.
Have you seen the Guowang satellites? Submit your photos here.
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.
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 18, 2024, the network reported 15 fireballs. (11 sporadics, 2 December Monocerotids, 1 December Leonis Minorid, 1 December Hydrid)
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]
Near Earth Asteroids
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 18, 2024 there were 2349 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.
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.
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