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A CME IS COMING: But it's not a big one. The sun launched the CME toward Earth on July 23rd, propelled by an erupting filament of magnetism near disk center. Although it is faint, the CME could still cause a G1-class geomagnetic storm when it arrives on July 27th. Aurora alerts: SMS Text
EQUATORIAL PLASMA BUBBLES ARE COMING FOR YOUR GPS: Earth's ionosphere is a bit like Swiss cheese. It contains holes called "equatorial plasma bubbles." If any of these bubbles drift across your sky--grip the steering wheel--your GPS might go haywire.
That's exactly what happened during a geomagnetic storm in March 2023. A new study published in the research journal Space Weather recounts how GPS radio signals began to rapidly flicker, akin to the twinkling of a star, causing positioning errors across a wide swath of the Americas.
GPS satellites transmitting through a bubbly ionosphere. Inset: a simulation of equatorial plasma bubbles. Video.
"This is the most intense event we have analyzed," says Fabiano Rodrigues, a physics professor at the University of Texas at Dallas and one of the paper's lead authors. "It produced extremely intense disruptions at low latitudes for more than 10 hours and was even detectable by our mid-latitude sensor in Dallas (UTD in the diagram below), which is unusual."
Completely surrounding Earth, the ionosphere is a shell of ionized gas created by the sun. Solar ultraviolet radiation ionizes air near the edge of space, creating a dynamic layer of plasma that varies with solar activity, time of day, and latitude. The ionosphere plays a critical role in GPS systems by reflecting or distorting radio waves passing through it.
When the sun sets, the ionosphere becomes unstable. This happens because the sun's ionizing radiation suddenly disappears. A Rayleigh-Taylor instability takes hold, and bubbles of low-density plasma begin to rise, much like blobs in a lava lamp.
These structures are especially common near the magnetic equator, where electric and magnetic fields enhance the effect. That's why they're called equatorial plasma bubbles.
The March 23-24, 2023, event was remarkable because the bubbles were so widespread. They are normally confined within +/- 20 degrees of the magnetic equator, but during this storm, they spread at least twice as far, affecting population centers at middle latitudes. Peak position errors were wider than urban roadways.
Above: Red-orange-yellow marks where rapid fluctuations were observed during the March 2023 geomagnetic storm. A plume of yellow extends all the way into Texas.
Savvy readers may wonder if something similar happened during the Great Geomagnetic Storm of May 2024. After all, that was the biggest geomagnetic storm in decades (G5+), far more intense than the March 2023 storm (G4). The answer, surprisingly, seems to be "no." The same sensors were running during both storms, yet only the lesser storm produced extraordinary scintillation.
"This is an example of how the ionosphere can respond differently to different magnetic storms," says Rodrigues. "We still have a lot to learn."
Do It Yourself: Rodrigues's team monitors equatorial plasma bubbles using a low-cost sensor called ScintPi, based on the Raspberry Pi computer. You can build one yourself. Hobbyists are using them to observe geomagnetic storms and even solar eclipses.
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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 Jul 23, 2025, the network reported 11 fireballs.
(10 sporadics, 1 Southern Delta Aquariid)
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 July 25, 2025 there were 2349 potentially hazardous asteroids.
 |
Recent & Upcoming Earth-asteroid encounters: | Asteroid | Date(UT) | Miss Distance | Velocity (km/s) | Diameter (m) |
| 2025 ME92 | 2025-Jul-20 | 13.4 LD | 5.3 | 31 |
| 2025 OP1 | 2025-Jul-21 | 3.1 LD | 7.8 | 7 |
| 2025 OR1 | 2025-Jul-21 | 12.1 LD | 12.3 | 20 |
| 2025 OA1 | 2025-Jul-22 | 13.7 LD | 7.2 | 26 |
| 2025 OZ | 2025-Jul-24 | 14 LD | 13.9 | 58 |
| 2025 OK1 | 2025-Jul-24 | 5.7 LD | 6.7 | 32 |
| 2025 OF2 | 2025-Jul-25 | 1.3 LD | 30.1 | 35 |
| 2025 OX | 2025-Jul-26 | 11.8 LD | 10.4 | 33 |
| 2025 OU1 | 2025-Jul-26 | 7 LD | 18.4 | 45 |
| 2018 BE5 | 2025-Jul-28 | 10.8 LD | 13.9 | 45 |
| 2025 OW | 2025-Jul-28 | 1.7 LD | 21 | 71 |
| 2025 ON1 | 2025-Jul-30 | 16.1 LD | 3.1 | 30 |
| 2025 OL1 | 2025-Jul-30 | 5.4 LD | 7.6 | 36 |
| 2025 OD1 | 2025-Jul-31 | 9.8 LD | 12.3 | 43 |
| 2025 OR | 2025-Jul-31 | 12.8 LD | 8 | 30 |
| 2025 OJ1 | 2025-Aug-08 | 13.4 LD | 14.2 | 91 |
| 2019 CO1 | 2025-Aug-08 | 17.8 LD | 10.5 | 65 |
| 2022 QB1 | 2025-Aug-10 | 8.9 LD | 3.9 | 6 |
| 2021 PJ1 | 2025-Aug-15 | 4.4 LD | 9.3 | 24 |
| 2025 CO3 | 2025-Aug-16 | 19.8 LD | 8.4 | 90 |
| 1997 QK1 | 2025-Aug-20 | 7.9 LD | 9.8 | 315 |
| 2022 QD3 | 2025-Aug-21 | 15 LD | 6.9 | 35 |
| 2023 PX | 2025-Aug-22 | 2.4 LD | 8.3 | 23 |
| 2019 QQ6 | 2025-Aug-24 | 9.4 LD | 17.2 | 31 |
| 2017 RK15 | 2025-Aug-29 | 15.8 LD | 13.2 | 26 |
| 2020 TS1 | 2025-Aug-29 | 17.8 LD | 3.3 | 5 |
| 1998 SH2 | 2025-Aug-30 | 8.1 LD | 17.3 | 246 |
| 2025 OG1 | 2025-Sep-05 | 14.4 LD | 4.2 | 34 |
| 2019 JG1 | 2025-Sep-09 | 18.8 LD | 7.9 | 17 |
| 2009 FF | 2025-Sep-11 | 6.8 LD | 12.9 | 155 |
| 2015 SA | 2025-Sep-13 | 10.3 LD | 9.1 | 31 |
| 2022 SS2 | 2025-Sep-13 | 2.4 LD | 7.2 | 13 |
| 2025 FA22 | 2025-Sep-18 | 2.2 LD | 10.8 | 164 |
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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