AI writing is everywhere -- except here. This website is written by Dr. Tony Phillips, a carbon-based lifeform with 30 yrs of forecasting experience. Our guarantee: If you find a mistake, it was made by a real human being.
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THE FIRST SOLAR WIND STREAM OF AUTUMN: Northern autumn begins on Tuesday, Sept. 22nd. The next day, a solar wind stream arrives. The incoming stream is flowing faster than 600 km/s from a canyon-shaped hole in the sun's atmosphere. Its arrival on Sept. 23rd will set the stage for the first equinox auroras of the new season. Aurora alerts: SMS Text
AURORAS LOVE EQUINOXES--BUT WHY? Autumn begins this week, and so does aurora season. The northern autumnal equinox arrives on Sept. 22nd. That is the cue for Arctic lights to switch on.
The reason is the Russell-McPherron effect. In 1973, UCLA researchers Christopher Russell and Robert McPherron figured out why geomagnetic activity has seasons. During the days and weeks around equinoxes, Earth's tilt lines up our planet's magnetic field with the sun's, and the two fields connect. This creates pathways and portals in the magnetosphere where solar wind can enter.
Above: Equinox auroras photographed 35,000 ft above Baffin Island by pilot Matt Melnyk.
In forecasting jargon, we say "BsubZ has tipped south." South-pointing magnetic fields from the sun partially cancel Earth's north-pointing field, and the door opens.
Because of the Russell-McPherron effect, Sept/Oct and March/April are the most geomagnetically active months of the year. Aurora-producing storms are about twice as likely around equinoxes as they are around the solstices of summer and winter.
Indeed, at this time of year, high-latitude auroras can appear for little apparent reason. A portal opens, ordinary solar wind enters, and voila--auroras!
Autumn darkness helps, too. The midnight sun has finally set on the Arctic, and nights there are long enough to see the show. The season runs until spring.
Would you like to know when BsubZ tips south? Instant alerts are available to Pro subscribers of our Space Weather Alert System.
Realtime Aurora Photo Gallery
Free: Spaceweather.com Newsletter
QUARTZ DIAMOND STUD EARRINGS: These earrings are out of this world. The Herkimer Quartz-Diamond Stud Earrings hitched a ride to the stratosphere onboard an Earth to Sky cosmic ray research balloon, floating 105,111 feet above California's Mono Lake:
You can have a pair for $199.95. Set in prongs of fine sterling silver, every Herkimer Quartz-Diamond is unique. Herkimer Diamonds are very sparkly clear quartz crystal specimens named after Herkimer County, New York - they were thought to be diamonds when first discovered there.
Your order comes with a full-color greeting card showing the earrings in flight with the Sierra landscape 115,111 ft below. The interior of the card tells the story of their flight to the edge of space and back.
Far Out Gifts: Earth to Sky Store
All sales support hands-on STEM education
Realtime Space Weather Photo Gallery
Free: Space Weather 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 September 19, 2026, the network reported 10 fireballs.
(10 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 21, 2026 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) |
| 2026 SU |
2026-Sep-16 |
11.2 LD |
10.1 |
11 |
| 2026 RF39 |
2026-Sep-16 |
5.7 LD |
7.7 |
20 |
| 2026 RM39 |
2026-Sep-16 |
4.3 LD |
9.8 |
10 |
| 2023 SZ3 |
2026-Sep-16 |
6.7 LD |
10.3 |
58 |
| 2026 RA4 |
2026-Sep-16 |
3.4 LD |
11.6 |
20 |
| 2026 RB39 |
2026-Sep-17 |
1 LD |
9.3 |
7 |
| 2026 NT2 |
2026-Sep-17 |
16.1 LD |
12.5 |
314 |
| 2026 RN4 |
2026-Sep-17 |
16.2 LD |
8.9 |
19 |
| 2026 SE |
2026-Sep-17 |
6.2 LD |
8.2 |
11 |
| 2026 SU2 |
2026-Sep-17 |
4.8 LD |
11.4 |
10 |
| 2026 RD38 |
2026-Sep-17 |
15.2 LD |
8.2 |
35 |
| 2026 SJ |
2026-Sep-18 |
6.9 LD |
8.5 |
15 |
| 2026 SO2 |
2026-Sep-18 |
5.3 LD |
9.8 |
20 |
| 2026 SR2 |
2026-Sep-18 |
3.2 LD |
7 |
8 |
| 2026 SG1 |
2026-Sep-18 |
14.4 LD |
10 |
26 |
| 2026 SW |
2026-Sep-18 |
10.8 LD |
8.4 |
18 |
| 2026 SK |
2026-Sep-19 |
4.3 LD |
16.2 |
17 |
| 2026 RF15 |
2026-Sep-19 |
5.5 LD |
14.1 |
27 |
| 2026 RH3 |
2026-Sep-19 |
17.2 LD |
11.7 |
29 |
| 2026 SS2 |
2026-Sep-20 |
5.6 LD |
10.6 |
37 |
| 2026 SA |
2026-Sep-20 |
4.2 LD |
10.6 |
17 |
| 2026 SF1 |
2026-Sep-20 |
15 LD |
6.2 |
19 |
| 2026 SH |
2026-Sep-20 |
10.2 LD |
13.3 |
25 |
| 2026 SG |
2026-Sep-20 |
3.2 LD |
14.5 |
25 |
| 2026 SS |
2026-Sep-20 |
2 LD |
15.5 |
8 |
| 2026 RP1 |
2026-Sep-20 |
20 LD |
17.2 |
42 |
| 2026 RW37 |
2026-Sep-20 |
1.2 LD |
8.7 |
8 |
| 2026 SZ2 |
2026-Sep-20 |
0.1 LD |
8 |
3 |
| 2026 SP2 |
2026-Sep-20 |
17.8 LD |
9.7 |
19 |
| 2026 SY |
2026-Sep-21 |
5.6 LD |
9.8 |
20 |
| 2026 SN2 |
2026-Sep-21 |
2.5 LD |
13.5 |
11 |
| 2026 SD3 |
2026-Sep-21 |
5.4 LD |
18.4 |
26 |
| 2026 SY2 |
2026-Sep-21 |
2.4 LD |
25.1 |
11 |
| 2026 SL |
2026-Sep-21 |
6.2 LD |
14.3 |
17 |
| 2026 RG39 |
2026-Sep-21 |
6.8 LD |
5.1 |
9 |
| 2026 RZ1 |
2026-Sep-22 |
10.4 LD |
9.1 |
36 |
| 2026 RD49 |
2026-Sep-22 |
15.8 LD |
3.7 |
18 |
| 2026 RA38 |
2026-Sep-22 |
14.7 LD |
8 |
24 |
| 2026 RJ15 |
2026-Sep-22 |
5.5 LD |
10.2 |
19 |
| 2026 SP |
2026-Sep-23 |
4.3 LD |
9.7 |
12 |
| 2026 SE1 |
2026-Sep-23 |
2.8 LD |
15.4 |
12 |
| 2026 RR34 |
2026-Sep-23 |
3.7 LD |
6.5 |
18 |
| 2026 RQ34 |
2026-Sep-24 |
13 LD |
7 |
24 |
| 2026 ST2 |
2026-Sep-24 |
15.9 LD |
13.7 |
42 |
| 2026 RC49 |
2026-Sep-24 |
11.1 LD |
8 |
22 |
| 2026 SC |
2026-Sep-25 |
1.7 LD |
7.8 |
21 |
| 2026 RN15 |
2026-Sep-27 |
8.4 LD |
6.5 |
21 |
| 2026 SL7 |
2026-Sep-28 |
17.7 LD |
26.9 |
46 |
| 2026 SX2 |
2026-Sep-28 |
4.1 LD |
7.7 |
13 |
| 2026 RS |
2026-Sep-30 |
11.2 LD |
6 |
25 |
| 2026 RX38 |
2026-Sep-30 |
10 LD |
14.3 |
33 |
| 2018 SP2 |
2026-Sep-30 |
5 LD |
14.3 |
39 |
| 2019 AS2 |
2026-Oct-02 |
4.5 LD |
7.3 |
49 |
| 2026 RP39 |
2026-Oct-03 |
6.1 LD |
6.1 |
21 |
| 2024 SH7 |
2026-Oct-04 |
10.5 LD |
10.8 |
12 |
| 2024 TD16 |
2026-Oct-07 |
14.2 LD |
11.8 |
17 |
| 2015 TS238 |
2026-Oct-08 |
4.7 LD |
15.8 |
30 |
| 2019 SD8 |
2026-Oct-10 |
18.7 LD |
9.5 |
12 |
| 2022 UP6 |
2026-Oct-15 |
2.6 LD |
9 |
8 |
| 2000 SZ162 |
2026-Oct-16 |
19.9 LD |
5.7 |
12 |
| 2020 FN3 |
2026-Oct-20 |
12.4 LD |
5.8 |
45 |
| 2017 UX7 |
2026-Oct-22 |
17 LD |
10.3 |
27 |
| 2018 GS1 |
2026-Oct-28 |
11.1 LD |
9.3 |
108 |
| 2022 UV21 |
2026-Oct-29 |
14.8 LD |
9.6 |
13 |
| 2025 UK9 |
2026-Oct-31 |
0.8 LD |
7.8 |
4 |
| 524522 |
2026-Nov-02 |
15.7 LD |
8.7 |
277 |
| 2021 VC4 |
2026-Nov-03 |
6 LD |
11.2 |
15 |
| 2017 WJ2 |
2026-Nov-05 |
15.6 LD |
11.8 |
118 |
| 2016 VZ1 |
2026-Nov-05 |
20 LD |
13.5 |
21 |
| 2001 KF54 |
2026-Nov-06 |
18.9 LD |
16.4 |
391 |
| 2025 UF5 |
2026-Nov-09 |
18.9 LD |
1.9 |
10 |
| 2015 VH65 |
2026-Nov-10 |
9.7 LD |
8 |
10 |
| 2012 YD7 |
2026-Nov-10 |
18.6 LD |
7.5 |
49 |
| 2023 VF3 |
2026-Nov-11 |
8.5 LD |
8.8 |
19 |
| 2022 MP2 |
2026-Nov-13 |
19.8 LD |
3.8 |
23 |
| 2025 VG5 |
2026-Nov-13 |
18.2 LD |
4.9 |
16 |
| 2023 VE6 |
2026-Nov-17 |
18.4 LD |
10.1 |
13 |
| 2019 WT1 |
2026-Nov-18 |
19.7 LD |
9.7 |
16 |
| 2018 NE1 |
2026-Nov-19 |
16.7 LD |
13.3 |
74 |
Notes: LD means
"Lunar Distance." 1 LD = 384,401 km, the distance
between Earth and the Moon. 1 LD also equals 0.00256
AU.
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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. |
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3D
views of the sun from NASA's Solar and Terrestrial
Relations Observatory |
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Realtime
and archival images of the Sun from SOHO. |
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information about sunspots based on the latest NOAA/USAF Active Region Summary |
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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 |
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from
the NOAA Space Environment Center |
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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 |
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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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