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SPACE WEATHER
NOAA Forecasts |
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Updated at: 2025 Dec 04 2200 UTC
FLARE |
0-24
hr |
24-48
hr |
CLASS M |
75
% |
75
% |
CLASS X |
25
% |
25
% |
Geomagnetic Storms:
Probabilities for significant
disturbances in Earth's magnetic field are given for three activity levels: active, minor
storm, severe
storm
Updated at: 2025 Dec 04 2200 UTC
Mid-latitudes
|
0-24
hr |
24-48
hr |
ACTIVE |
35
% |
30
% |
MINOR |
20
% |
15
% |
SEVERE |
05
% |
01
% |
High latitudes
|
0-24
hr |
24-48
hr |
ACTIVE |
10
% |
15
% |
MINOR |
30
% |
30
% |
SEVERE |
55
% |
45
% |
|
|
|
 |
|
|
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| |
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| |
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.
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GEOMAGNETIC STORM WATCH: Improved models of yesterday's CME suggest that it might hit Earth, after all. A glancing blow (or near miss) is possible on Dec. 7th, potentially sparking a minor G1-class geomagnetic storm. The CME was launched on Dec. 4th by an M6-class solar flare from sunspot 4300. Aurora alerts: SMS Text.
THE SODIUM TAIL OF MERCURY: The biggest comet in the Solar System is actually a planet. It’s Mercury. On Dec. 3rd, Steven Bellavia photographed Mercury's magnificent tail from Surry, Virginia:
"This 24 million kilometer plume of gas is being ejected from Mercury due to the sun, very much like a comet," says Bellavia.
First predicted in the 1980s, Mercury’s tail was discovered in 2001. Its source is Mercury’s super-thin atmosphere. Mercury is so close to the sun, pressure from sunlight pushes atoms out of the atmosphere and into space. The most important atom is sodium, which strongly scatters sunlight and gives the tail a yellow hue. Bellavia used a narrowband filter to capture the bright yellow sodium light at 589nm.
Mercury's tail waxes and wanes in brightness 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).
That special date is less than a week away: On Dec. 9th, Mercury will be 16 days past perihelion and the tail could be as much as 10 times brighter than what Bellavia saw. Take a look! Just don’t forget your sodium filter….
Realtime Space Weather Photo Gallery
Free: Spaceweather.com Newsletter
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.
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 "EARTHTOSKY" at checkout for a 10% holiday discount.
Far Out Gifts: Earth to Sky Store
All sales support hands-on STEM education
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. 04 2025, the network reported 8 fireballs.
(5 sporadics, 2 sigma_Hydrid, 1 November omega Orionid)
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 5, 2025 there were 2349 potentially hazardous asteroids.
 |
Recent
& Upcoming Earth-asteroid encounters:
| Asteroid |
Date(UT) |
Miss Distance |
Velocity (km/s) |
Diameter (m) |
| 2025 WQ3 |
2025-Nov-29 |
8.4 LD |
2.4 |
10 |
| 2025 WP8 |
2025-Nov-29 |
1.4 LD |
11.4 |
8 |
| 2025 WA10 |
2025-Nov-29 |
16.1 LD |
8.1 |
25 |
| 2025 WB3 |
2025-Nov-29 |
7.9 LD |
10.4 |
17 |
| 2025 WO8 |
2025-Nov-29 |
0.3 LD |
7.4 |
5 |
| 2025 WE14 |
2025-Nov-29 |
0.1 LD |
20.8 |
5 |
| 2025 WT6 |
2025-Nov-30 |
2 LD |
9.2 |
10 |
| 2025 WS6 |
2025-Nov-30 |
4.6 LD |
12.2 |
16 |
| 2025 WU9 |
2025-Nov-30 |
1.9 LD |
5.9 |
8 |
| 2025 WZ3 |
2025-Nov-30 |
1.2 LD |
17.9 |
14 |
| 2025 WM4 |
2025-Nov-30 |
0.7 LD |
14.1 |
17 |
| 2025 WG16 |
2025-Dec-01 |
4.3 LD |
10.8 |
28 |
| 2025 WY15 |
2025-Dec-01 |
7.9 LD |
8.7 |
25 |
| 2025 WH6 |
2025-Dec-01 |
8.2 LD |
17.4 |
20 |
| 2007 VM184 |
2025-Dec-01 |
13.1 LD |
20 |
219 |
| 2025 WG |
2025-Dec-02 |
5.1 LD |
7.2 |
18 |
| 2018 WC2 |
2025-Dec-02 |
16.1 LD |
8.4 |
36 |
| 2025 WO9 |
2025-Dec-03 |
9.1 LD |
6.1 |
13 |
| 2025 WC10 |
2025-Dec-03 |
8.1 LD |
7.3 |
12 |
| 2025 WN1 |
2025-Dec-03 |
11.1 LD |
2.8 |
45 |
| 2025 WP16 |
2025-Dec-03 |
1.1 LD |
11.4 |
6 |
| 2014 WC364 |
2025-Dec-03 |
10.3 LD |
12.5 |
39 |
| 2025 UF10 |
2025-Dec-04 |
14.5 LD |
13.1 |
133 |
| 2025 VE6 |
2025-Dec-04 |
6.3 LD |
5.2 |
22 |
| 2025 WM3 |
2025-Dec-05 |
14.1 LD |
10.7 |
27 |
| 2025 WF10 |
2025-Dec-06 |
18.3 LD |
4.3 |
40 |
| 2025 WD10 |
2025-Dec-06 |
7.7 LD |
6.9 |
15 |
| 2025 WB10 |
2025-Dec-06 |
3.9 LD |
7.5 |
13 |
| 2025 WD5 |
2025-Dec-06 |
7.8 LD |
22.5 |
48 |
| 2025 WW13 |
2025-Dec-07 |
9.9 LD |
7.3 |
18 |
| 2025 WO13 |
2025-Dec-07 |
19.6 LD |
7.7 |
30 |
| 2021 JE1 |
2025-Dec-08 |
13.5 LD |
7.1 |
16 |
| 2025 WK4 |
2025-Dec-10 |
8.9 LD |
5.5 |
31 |
| 2019 XN3 |
2025-Dec-10 |
5.7 LD |
3.6 |
15 |
| 1999 SF10 |
2025-Dec-10 |
8.2 LD |
4.4 |
46 |
| 2025 WY9 |
2025-Dec-13 |
14.5 LD |
5.3 |
19 |
| 2016 YH |
2025-Dec-13 |
6.8 LD |
8.9 |
28 |
| 2025 TZ |
2025-Dec-15 |
17.8 LD |
6.2 |
53 |
| 2025 WA14 |
2025-Dec-15 |
20 LD |
9.3 |
34 |
| 2025 WA3 |
2025-Dec-15 |
8.9 LD |
19.4 |
251 |
| 2025 WD4 |
2025-Dec-17 |
19.9 LD |
12.8 |
43 |
| 2025 WN6 |
2025-Dec-17 |
15.9 LD |
2.9 |
37 |
| 2015 XX168 |
2025-Dec-18 |
4.7 LD |
11.6 |
27 |
| 2010 WR7 |
2025-Dec-20 |
19.4 LD |
8.3 |
71 |
| 2025 WT3 |
2025-Dec-22 |
16 LD |
4.5 |
26 |
| 2021 AB1 |
2025-Dec-28 |
10.2 LD |
12.3 |
16 |
| 2019 AU |
2025-Dec-30 |
19.3 LD |
2.8 |
16 |
| 2024 AV2 |
2025-Dec-30 |
17.9 LD |
7 |
17 |
| 2014 AF16 |
2026-Jan-04 |
9 LD |
9.6 |
34 |
| 2023 XM15 |
2026-Jan-07 |
15.2 LD |
6.9 |
51 |
| 2022 GR3 |
2026-Jan-12 |
14.5 LD |
12.9 |
9 |
| 2022 OB5 |
2026-Jan-14 |
1.7 LD |
2.2 |
6 |
| 2025 BL |
2026-Jan-17 |
4.7 LD |
6.9 |
28 |
| 2004 MO3 |
2026-Jan-17 |
17 LD |
10.2 |
129 |
| 2011 AM37 |
2026-Jan-17 |
19.8 LD |
5.1 |
4 |
| 2019 LZ4 |
2026-Jan-23 |
14.2 LD |
11.6 |
45 |
| 2022 AG |
2026-Jan-29 |
13.7 LD |
5.3 |
34 |
| 2020 GE |
2026-Jan-29 |
16.2 LD |
1.2 |
8 |
| 2023 RX1 |
2026-Jan-31 |
8.8 LD |
1.2 |
3 |
| 2022 OC3 |
2026-Jan-31 |
1.3 LD |
3.8 |
8 |
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 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.
| |
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 |
 |
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