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A CME IS HEADING FOR INTERSTELLAR COMET ATLAS: How often does a CME from our own sun strike a comet from interstellar space? It's rare, so tomorrow's collision is worth watching. Monitoring NASA forecast models, physicist Marshall Eubanks of Space Initiatives Inc realized that a CME launched on Sept. 19th will reach the location of Comet 3I/ATLAS on Sept. 24th or 25th. Observers should be alert for irregularities in the comet's stubby tail, which could be bent or disconnected.
This timing of the CME's potential impact is fortuitous. It comes only a week before the comet disappears into the glare of the sun, giving Earth-based astronomers a narrow window of opportunity to record the event. It also coincides with the comet's recent brightening. Images taken by Gerald Rhemann and Michael Jäger show that it is now a 12th magnitude object:
"We can confirm Thomas Lehmann’s recent detection of the comet’s increase in brightness," says Jäger. Since early September, Comet ATLAS has brightened by a factor of 40, making it far easier to observe even as it drops lower into the sun’s glare.
The majority of the increase is in only one color: Green. This is a sign that gas production in the comet is ramping up as it approaches the sun. The key compound is diatomic carbon (C2), a reactive molecule that emits green light when it is energized by ultraviolet radiation from the sun.
This plot from Marshall Eubanks shows what is probably happening:
His model breaks the comet's brightness into two pieces--a contribution from dust (red line) and a contribution from gas (blue dashed line). The surging gas component is making the comet bright just in time for its early-October encounter with Mars and Earth's fleet of spacecraft orbiting the Red Planet. We will cover *that* later this week. Stay tuned!
Realtime Comet ATLAS Photo Gallery
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SOLAR ECLIPSE OBSERVED FROM SPACE (UPDATED): This could be a first. On Sept. 21st, NOAA's CCOR-1 coronagraph onboard GOES-19 observed a solar eclipse from Earth orbit. Watch the lights go out as the Moon zig zags between the satellite and the sun:
To our knowledge, this is the first natural solar eclipse ever observed by a space-based coronagraph. CCOR-1 is the first coronagraph in Earth's orbit, where such an event could be seen.
Coronagraphs are designed to create artificial eclipses, blocking the glare of the sun so that space weather forecasters can see faint CMEs. That makes Sunday's event an eclipse of an eclipse.
Regular readers of spaceweather.com may know that the Moon zips through CCOR-1's field of view once a month. Usually it crosses in a straight line. We're not sure why it zig-zagged this time, but it may be related to a yaw flip maneuver scheduled on Sept. 22nd to help calibrate the coronagraph.
Update: During the eclipse, the Moon covered only the disk of the sun, yet the entire corona vanished. If you're wondering why, Bill Thompson of the Goddard Space Flight Center has the answer: "It's a result of image processing," he explains. "Normally, each image seen by CCOR-1's detector is a combination of the corona and bright sunlight scattered within the telescope. A model of the scattered light is subtracted to reveal the corona. During the eclipse, the scattered light went away, but the subtraction proceded as if it hadn't. It ended up subtracting too much."
Realtime Solar Eclipse Photo Gallery
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AMBER SPACE DRGONFLY: This dragonfly has touched space. On Sep. 15, 2025, the students of Earth to Sky Calculus launched it to the stratosphere onboard a cosmic ray research balloon, 101,148 feet above California's Sierra Nevada mountains:
You can have it for $169.95. Made of genuine Baltic Amber with a sterling silver exoskeleton, the rich Cognac-colored pendant measures 3/4 inch and comes with a matching 18-inch sterling silver chain.
The students are selling space pendants to pay the helium bill for their cosmic ray ballooning program. Each one comes with a greeting card showing the ornament in flight and telling the story of its trip to the stratosphere and back again.
Far Out Gifts: Earth to Sky Store
All sales support hands-on STEM education
Realtime Space Weather 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 Sep 22, 2025, the network reported 7 fireballs.
(7 sporadics)
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 September 23, 2025 there were 2349 potentially hazardous asteroids.
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Recent
& Upcoming Earth-asteroid encounters:
| Asteroid |
Date(UT) |
Miss Distance |
Velocity (km/s) |
Diameter (m) |
| 2025 RT3 |
2025-Sep-18 |
2.7 LD |
15.1 |
13 |
| 2025 SC |
2025-Sep-18 |
1.2 LD |
3.2 |
3 |
| 2025 FA22 |
2025-Sep-18 |
2.2 LD |
10.8 |
166 |
| 2025 RC2 |
2025-Sep-18 |
4.2 LD |
18.6 |
19 |
| 2025 SZ2 |
2025-Sep-18 |
13.3 LD |
12.3 |
27 |
| 2025 RP2 |
2025-Sep-19 |
11.3 LD |
7.7 |
29 |
| 2025 SZ1 |
2025-Sep-19 |
3.3 LD |
11.2 |
18 |
| 2025 SX2 |
2025-Sep-19 |
3.7 LD |
6.4 |
22 |
| 2025 RL2 |
2025-Sep-19 |
0.6 LD |
9.7 |
22 |
| 2025 SY1 |
2025-Sep-19 |
0.1 LD |
7.9 |
2 |
| 2025 RW3 |
2025-Sep-19 |
4.2 LD |
15.1 |
12 |
| 2025 SL2 |
2025-Sep-19 |
18.4 LD |
14.4 |
27 |
| 2025 RD4 |
2025-Sep-20 |
6.4 LD |
19.3 |
19 |
| 2025 SH2 |
2025-Sep-20 |
11 LD |
14.2 |
20 |
| 2025 ST1 |
2025-Sep-21 |
4.9 LD |
8 |
12 |
| 2025 SO1 |
2025-Sep-21 |
9.7 LD |
11.4 |
29 |
| 2025 SN4 |
2025-Sep-21 |
1.9 LD |
10.7 |
29 |
| 2025 RE6 |
2025-Sep-21 |
5.4 LD |
13.4 |
8 |
| 2025 PJ1 |
2025-Sep-21 |
11.6 LD |
11.8 |
131 |
| 2025 SK3 |
2025-Sep-22 |
6.7 LD |
8.6 |
13 |
| 2025 SF4 |
2025-Sep-22 |
16.4 LD |
8.2 |
42 |
| 2025 SG4 |
2025-Sep-22 |
18.4 LD |
10.3 |
41 |
| 2025 RO3 |
2025-Sep-22 |
9.1 LD |
16.8 |
34 |
| 2022 SW12 |
2025-Sep-23 |
15 LD |
17.6 |
211 |
| 2025 SP3 |
2025-Sep-23 |
1.1 LD |
12.3 |
7 |
| 2018 QT1 |
2025-Sep-23 |
13.1 LD |
12.7 |
134 |
| 2025 SR3 |
2025-Sep-23 |
16.8 LD |
24.2 |
68 |
| 2021 RN16 |
2025-Sep-23 |
10.1 LD |
8.8 |
7 |
| 2025 SM2 |
2025-Sep-23 |
6.6 LD |
13.2 |
17 |
| 2025 SX |
2025-Sep-24 |
14.9 LD |
5 |
16 |
| 2025 RX3 |
2025-Sep-25 |
15.1 LD |
11.2 |
17 |
| 2025 RX4 |
2025-Sep-25 |
2.8 LD |
10 |
40 |
| 2025 SB4 |
2025-Sep-25 |
3.7 LD |
17.6 |
23 |
| 2025 SW |
2025-Sep-25 |
4.2 LD |
8.1 |
99 |
| 2025 SS |
2025-Sep-25 |
5 LD |
8.9 |
29 |
| 2025 RC4 |
2025-Sep-25 |
8.5 LD |
10 |
20 |
| 2025 RE5 |
2025-Sep-26 |
17.7 LD |
7.9 |
26 |
| 2025 SU3 |
2025-Sep-26 |
18.3 LD |
9.9 |
39 |
| 2025 SD4 |
2025-Sep-26 |
4.6 LD |
19.3 |
24 |
| 2025 SA1 |
2025-Sep-28 |
5 LD |
8.7 |
21 |
| 2019 SF6 |
2025-Sep-28 |
20 LD |
8.4 |
20 |
| 2025 SC4 |
2025-Sep-29 |
19.3 LD |
5.5 |
23 |
| 2025 RH4 |
2025-Sep-29 |
17.9 LD |
17.3 |
52 |
| 152664 |
2025-Sep-29 |
10.1 LD |
18.6 |
412 |
| 2023 EH2 |
2025-Sep-30 |
19.8 LD |
17.8 |
51 |
| 2025 SA3 |
2025-Sep-30 |
7 LD |
7.2 |
17 |
| 2025 SZ |
2025-Oct-01 |
9 LD |
2 |
8 |
| 2025 QL23 |
2025-Oct-01 |
7.1 LD |
10 |
75 |
| 2025 SY |
2025-Oct-02 |
12.2 LD |
5.9 |
15 |
| 2025 SH |
2025-Oct-02 |
3.6 LD |
3.7 |
12 |
| 2020 GE1 |
2025-Oct-02 |
13.7 LD |
4.7 |
14 |
| 2025 RH2 |
2025-Oct-03 |
19.6 LD |
5.1 |
37 |
| 2018 SP1 |
2025-Oct-05 |
13.2 LD |
16.4 |
85 |
| 2022 TU1 |
2025-Oct-08 |
16.9 LD |
12.9 |
10 |
| 2020 QU5 |
2025-Oct-09 |
7.1 LD |
13.6 |
26 |
| 2022 AY5 |
2025-Oct-14 |
7.4 LD |
8.4 |
5 |
| 2022 UY3 |
2025-Oct-15 |
10.2 LD |
7.4 |
15 |
| 2022 UU15 |
2025-Oct-19 |
14.8 LD |
16.1 |
34 |
| 2023 UK3 |
2025-Oct-21 |
6.7 LD |
9 |
5 |
| 2024 GD2 |
2025-Oct-22 |
17.8 LD |
4.2 |
28 |
| 2022 HM1 |
2025-Oct-23 |
15.1 LD |
13.3 |
27 |
| 2012 TP231 |
2025-Oct-25 |
15.2 LD |
6.7 |
37 |
| 2020 FA5 |
2025-Oct-26 |
15.7 LD |
26.5 |
210 |
| 2009 HC |
2025-Oct-26 |
8.6 LD |
4.2 |
39 |
| 434196 |
2025-Oct-27 |
17.4 LD |
10.9 |
171 |
| 2023 VK6 |
2025-Nov-03 |
7.6 LD |
9.6 |
15 |
| 2021 VQ10 |
2025-Nov-08 |
9 LD |
15 |
13 |
| 2019 UH7 |
2025-Nov-08 |
13.3 LD |
5.8 |
11 |
| 2018 KC |
2025-Nov-09 |
16 LD |
9.3 |
11 |
| 2017 WG14 |
2025-Nov-09 |
16.7 LD |
11.7 |
45 |
| 2020 VK4 |
2025-Nov-10 |
16.4 LD |
3.8 |
9 |
| 2012 VC26 |
2025-Nov-11 |
13.3 LD |
6.4 |
6 |
| 2019 VL5 |
2025-Nov-14 |
14.7 LD |
9.1 |
24 |
| 2022 FG4 |
2025-Nov-17 |
18.7 LD |
22.2 |
105 |
| 3361 |
2025-Nov-19 |
14.8 LD |
9.1 |
435 |
| 2013 NJ4 |
2025-Nov-20 |
12.6 LD |
6.4 |
12 |
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.
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The
official U.S. government space weather bureau |
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The
first place to look for information about sundogs,
pillars, rainbows and related phenomena. |
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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. |
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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. |
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from the NOAA Space Environment Center |
| |
the
underlying science of space weather |
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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. |
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