Study Findings: Regression to the Mean Can Explain Saturation of Geomagnetic Storms

Posted on by onespaceman2000
Image (Credit): A May 2024 image of a solar flare captured by NASA’s Solar Dynamics Observatory (SDO). (NASA SDO)

Nature abstract of study findings:

Extreme space weather events on Earth occur during intervals of strong solar wind driving. The solar wind drives plasma convection and currents in the near-Earth space environment. For low values of the driver, the Earth’s response is linear, estimated by parameters such as the polar cap index based on ground magnetometer activity. Curiously, for extreme solar wind driving, the Earth’s response appears not to increase beyond a saturation limit. Theorists have advanced a host of explanations for this saturation effect, but there is no consensus. Here we demonstrate that this saturation is a manifestation of the regression to the mean effect arising from random uncertainty in the timing and magnitude of solar wind measurements. Our results reveal that data analysis underpinning the saturation theories is nonlinearly biased, thereby challenging the validity of the theories. Correcting for the uncertainties reveals that the Earth’s response to solar wind driving is linear throughout, and that the impact of extreme geomagnetic storms can be twice as large as previously thought. We show that regression to the mean is a fundamental property of the relationship between measurement and the truth, where the truth corresponding to the measurement is closer to the mean. This effect is particularly pronounced for uncertain measurements of extreme values and is likely to manifest across various fields, from extreme climate studies to chronic medical pain.

Citation: Sivadas, N., Sibeck, D., Subramanyan, V. et al. Regression to the mean can explain saturation of geomagnetic storms. Nature 655, 1143–1147 (2026).

DOI: https://doi.org/10.1038/s41586-026-10757-4

Study-related stories:

Wired – “An Extreme Solar Storm May Be Even More Devastating Than Previously Imagined”

SciTechDaily – “Earth May Be Twice As Vulnerable to Extreme Solar Storms As Scientists Thought”

NASA – “New NASA Study Says Possibly No Limit to Solar Storm Effects”

Pic of the Week: Preparing the Nancy Grace Roman Space Telescope

Posted on by onespaceman2000
Image (Credit): Members of NASA’s Nancy Grace Roman Space Telescope propellant, safety, and quality assurance team. (NASA/Sydney Rohde (Rocz))

The image above, taken on July 20th, shows one of the many teams working on the Nancy Grace Roman Space Telescope as it gets ready for its launch on August 30th. The pictured individuals are part of the propellant, safety, and quality assurance team.

NASA’s latest update on the mission stated:

Technicians completed fueling NASA’s Nancy Grace Roman Space Telescope, bringing it an important step closer to launch. On July 25, the team completed operations that carefully loaded 290 gallons of hydrazine fuel into the observatory at the Payload Hazardous Servicing Facility at NASA’s Kennedy Space Center in Florida.

After launch and separation from the rocket, Roman will use this onboard propellant to perform maneuvers as it travels to Sun-Earth Lagrange point 2, or L2, located about one million miles from Earth. There, about four times the distance to the Moon, it will have an ideal home for astronomy.

Space Quote: Two Spacecraft Are Now Imperiled

Posted on by onespaceman2000
Image (Credit): Artist’s rendering of the LINK spacecraft in the Pegasus XL Rocket after launch. (Northrop Grumman)

“Over the weekend, Katalyst’s LINK servicing spacecraft experienced issues with attitude control, causing the spacecraft to spin and resulting in sporadic communications. Preliminary investigation shows that two of LINK’s three reaction wheels currently are not operable, and there is some loss of functionality in its cold gas thruster system. LINK is designed to approach, capture, and boost NASA’s Neil Gehrels Swift Observatory to a higher orbital altitude.”

-Statement by NASA regarding the private sector LINK mission to save the Neil Gehrels Swift Observatory, which is slowly losing altitude and is expected to burn up in the atmosphere by year’s end if nothing is done. The LINK mission was launched from the Marshall Islands on July 3rd aboard a Pegasus rocket.

Astronomy Question: The Durability of Apollo Remains

Posted on by onespaceman2000
Image (Credit): A close-up view of an astronaut’s bootprint in the lunar soil during the Apollo 11 mission. (NASA/Edwin “Buzz” Aldrin)

Multiple Choice: For how long will signs of the the earlier Apollo missions (e.g., footprints, equipment, flag, etc.) be visible on the Moon’s surface?

A. 1-10 million years
B. 10-100 million years
C. 100-500 million years
D. More than 500 million years

Take a guess and then check your answer by going to the “Astronomy Question Answer Sheet” page.

Starship’s 13th Test a Needed Success

Posted on by onespaceman2000
Credit: SpaceX

After some delays, SpaceX’s Starship rocket is back in testing mode, with yesterday’s 13th launch a success. The rocket met the milestones set for the mission, and even launched a batch of satellites. This should give SpaceX and NASA some breathing room, as well as the new investors in SpaceX.

Mr. Musk had a bad week with both Tesla and SpaceX stock struggling. While SpaceX stock fell approximately 7 percent during the five days preceding the launch, the market should be somewhat more confident on Monday morning following the successful test.

Reuters reported last week that short sellers betting against SpaceX are making a fortune to the tune of about $8.7 billion. Mr. Musk may not like this, but if you want to be part of the marketplace then you need to understand how the market works.

In stocks, what goes up can often come down, and it can be painful to watch. As a rocket man, Mr. Musk should be familiar with this.

Maybe his success with Starship on Friday will turn some of that around.