Spotless Days
Current Stretch: 0 days
2025 total: 0 days (0%)
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 21 Nov 2025
Thermosphere Climate Index
today: 22.42x1010 W Warm
Max: 49.4x1010 W Hot (10/1957)
Min: 2.05x1010 W Cold (02/2009)
explanation | more data: gfx, txt
Updated 21 Nov 2025
The Radio
Sun
10.7 cm flux: 121 sfu
explanation | more
data
Updated 22 Nov 2025
Cosmic Rays Solar Cycle 25 is near its peak, 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: -10.9%Very Low
48-hr change: -1.5%
Max: +11.7% Very High (12/2009)
Min: -32.1% Very Low (06/1991)
explanation |more data
Updated 22 Nov 2025 @ 0700 UT
This is an AI Free Zone: Text created by Large Language Models is spreading 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.
WHERE IS INTERSTELLAR COMET 3I/ATLAS? Answer: In the constellation Virgo. You can find 3I/ATLAS in the morning sky (look east before sunrise) very close to the 4th magnitude star eta Virginis. The comet itself is 10th magnitude, so it is a relatively easy target for mid-sized backyard telescopes. Sky maps: Nov. 23, 24, 25, 26.
INTERSTELLAR COMET 3I/ATLAS IN COLOR: Who needs satellites and space agencies? Using a backyard telescope on Earth, amateur astronomers Michael Jäger and Gerald Rhemann have just captured the best-yet color image of interstellar visitor 3I/ATLAS. It is unmistakably a comet.
"We used a 12-inch telescope with a QHY600 cooled astronomy camera and color filters," says Jäger.
With one exception (discussed below), the photo is "classic comet." The comet's long tail streams straight away from the sun, sculpted by solar wind. Its blue color comes from carbon monoxide ions, CO+, a compound found in almost all Solar System comets. The comet's head is green because of another common molecule, diatomic carbon (C2), which is released from icy comet cores when they get close to the sun.
Now for the exception: There is a jet poking out of 3I/ATLAS's head toward the sun. It stands out in this black-and-white image taken by Michael Jäger and Gerald Rhemann on Nov. 20th:
This is unusual. Solar System comets rarely have such "anti-tails." This has prompted some (actually just one) astronomer to suggest that 3I/ATLAS might have an artificial thruster.
There is, however, a completely natural explanation. 3I/ATLAS spent a very long time in interstellar space. Billions of years of cosmic ray bombardment may have altered its surface--knocking hydrogen atoms out while heavier molecules remained behind. Now that 3I/ATLAS is in our solar system, sunlight is warming that crust and causing it to shed relatively large, heavy grains of dust. These grains are too massive to be quickly pushed around by radiation pressure or the solar wind. Instead they linger, creating a sunward-pointing jet that does not bend backward like a normal tail.
The backyard conclusion: 3I/ATLAS is a comet, and a wonderful one.
Realtime Comet Photo Gallery
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THE HYDROGEN-ALPHA RING FOR MEN: The Earth to Sky Store sells a lot of gifts for women. This one is for men. It's the Hydrogen Alpha Ring, returning from a trip to the stratosphere on Nov. 16th.
You can have it for 126ドル.95. The Hydrogen-Alpha Ring is the same color that hydrogen atoms emit in the sun's hot atmosphere: Red at a wavelength of 656 nanometers. Space-black edges of beveled tungsten carbide frame the deep-red band.
Multiple sizes were flown. If you're not sure, select size "11" during the checkout process; that fits most fingers. Your purchase comes with a greeting card showing the ring in flight, and telling the story of its journey to the edge of space.
Far Out Gifts: Earth to Sky Store
All sales support hands-on STEM education
Realtime Space Weather Photo Gallery
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Realtime Aurora Photo Gallery
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On Nov 21, 2025, the network reported 10 fireballs.
(4 sporadics, 3 Leonids, 3 Northern Taurids)
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]
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 sharply 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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