GEOMAGNETIC STORM WATCH (G3): Three and perhaps four CMEs are heading for Earth following a series of explosions on the sun this week. Estimated time of arrival: Nov. 30th and Dec. 1st. The biggest of the CMEs, launched on Nov. 28th, could sweep up some of the earlier, lesser ones, forming a Cannibal CME capable of sparking strong G3-class geomagnetic storms with mid-latitude auroras. Aurora alerts: SMS Text
ALMOST-X CLASS SOLAR FLARE: Sunspot AR3500 erupted on Nov. 28th (1950 UT), producing an M9.8-class solar flare (only percentage points below category X). NASA’s Solar Dynamics Observatory recorded the blast:
A pulse of extreme ultraviolet radiation blacked out shortwave radio communications across the South Pacific Ocean and parts of the Americas: map. Mariners and ham radio operators may have noticed loss of signal at frequencies below ~20 MHz for as much as an hour after the flare.
Of greater interest is the CME. The explosion hurled one directly toward Earth. This SOHO coronagraph movie shows a halo cloud expanding in our direction faster than 800 km/s (1.8 million mph):
According to a NASA model, this CME will strike Earth midday (UT) on Dec. 1st. It might sweep up one of several slower CMEs ahead of it. If so, it could form a Cannibal CME capable of causing a strong G3-class geomagnetic storm. CME alerts: SMS Text
STARLINK MOON HALO: Another batch of 23 Starlink satellites soared into orbit onboard a Space X Falcon 9 rocket Monday night from Cape Canaveral. Just after liftoff, the rocket pierced a thin layer of icy clouds, setting the stage for this picture:
“The Starlink schedule has increased so much that that there is a launch every week from Cape Canaveral,” says photographer Dr. Gilbert Plumer of Rockledge, Florida, only 20 miles from the Cape. “Cirrus clouds made a halo around the full Moon, adding some beauty to the liftoff.”
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 Nov 28, 2023, the network reported 9 fireballs.
(8 sporadics, 1 Leonid)
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 7 years, resulting in a unique dataset of in situ atmospheric measurements.
Latest results (July 2022): Atmospheric radiation is decreasing in 2022. Our latest measurements in July 2022 registered a 6-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.
