Category Archives: aurora

The Great Storm of May 10, 2024

We just passed through the biggest ‘solar storm’ in the last 20 years caused by the massive naked-eye sunspot group called AR-3664. Its size was 15 times the diameter of Earth and rivaled the size of the famous Carrington sunspot of September, 1859. Since it first appeared on May 2, it remained inactive until May 9 when it released an X2.2-class solar flare at 10:10 UT.

This enormous and violent release of energy stimulated the launch of six coronal mass ejections of which three merged to become an intense ‘cannibal CME’ that arrived near Earth on May 10 at 16:45 UT. Its south-directed magnetic field was perfect for imparting the maximum amount of energy to our planet’s magnetosphere. For a transit time of about 24-hours, it was traveling at a speed of about 1,700 km/s when it arrived. It sparked a G5-level extreme geomagnetic disturbance with a Kp index of 9 between May 10, 21:00 UT and May 11, 03:00 UT. The image below was taken by Tom Wasiela on May 10, 2024 from Roanoke, Virginia and is courtesy of the SpaceWeather Gallery. Reports suggest that aurora were seen as far south as Florida and Puerto Rico.

Taken by Tom Wasiela on May 10, 2024 @ Roanoke, Virginia

On May 9th at 06:54 UT AR-3664 produced an X-3.9 flare. This was followed on May 11 with a fourth major X-5.8 flare at 1:39 UT, which caused an immediate shortwave radio blackout across the entire Pacific Ocean that lasted for several hours. It is expected that the May 11 flare sparked anoher CME that may arrive near Earth on Monday evening May 13.

The last G5 geomagnetic storm that we experienced was way back in October 28 to November 5, 2003. These Halloween Storms caused power outages in Sweden and damaged transformers in South Africa. Despite many recent cautionary comments in the news media about cellphone and satellite outages and power grid problems, as yet none of these have been identified but perhaps in the next few weeks these technological impacts may start to be mentioned as anecdotes begin to surface.  

Unfortunately, many areas on the East Coast were covered by clouds during this three-day period and missed the opportunity to see these major aurorae. However, my DIY magnetometer (see my earlier blog on how to build your own $50 magnetometer (located in Kensington, Maryland (latitude 39o N) was able to keep up with the invisible changes going on, and produced a very respectable record of this entire storm period. As a scientist, I am often working with things I cannot directly see with my eyes, so the fact that I had my trusty magnetometer to reveal these invisible changes around me was pretty cool!

This graph shows a side-by-side comparison of the data recorded by my RM3100 magnetometer (black) and the magnetometer at the Fredericksberg Magnetic Observatory (red). I have shifted and rescaled the plots so you can more easily see how similar they are. This is very satisfying because it shows that even a simple home-made magnetometer can perform very well in keeping up with the minute changes in the geomagnetic field. This plot shows the variation in the so-called D component, which is the local magnetic declination angle. Mathematically is is defined by D = arctan(Bx/By). It’s the angle relative to geographic North that your local compass points.

Below is a slightly different graph of the RM3100 data. As you can see in the first part of the above plot between 36 and 63 UT hours, the smooth change is caused by the diurnal Sq current effect that is correlated with the solar elevation angle. During this storm period, it is assumed to have behaved smoothly during the actual storm, so in the graph below I have subtracted it from the magnetometer data. The result is that I have now isolated the changes due to the storm itself. The top row of numbers are the 3-hour Kp index averages from NOAA. The marked times are for EDT in Maryland. Universal Time is 4 hours ahead of EDT.

This was, indeed, a very powerful storm that lasted about 42 hours. This places it among a handful of exceptional geomagnetic storms that includes the great Carrington Storm of August 28 to Septemer 5, 1859.

Why is this important? Well, in the grand scheme of things it may not matter much, but as an astronomer it is still a lot of fun to have access to the invisible universe from the comfort of my suburban home. I will let geophysicists have all the fun deciphering all the bumps and wiggles and what they tell us about our magnetic field and solar storms!

Meanwhile, my gear is primed and ready to go to detect this Monday’s next storm. Some predict that it may be even bigger then the one we just experienced. It’s interesting how the Carrington Storm was actually two major storms separated by a few days, with the CME from the first storm also canibalizing several other CMEs that were also enroute.

Exploring the Heliosphere

This is my new book for the general public about our sun and its many influences across the solar system. I have already written several books about space weather but not that specifically deal with the sun itself, so this book fills that gap.

We start at the mysterious core of the sun, follow its energies to the surface, then explore how its magnetism creates the beautiful corona, the solar wind and of course all the details of space weather and their nasty effects on humans and our technology.

I have sections that highlight the biggest storms that have upset our technology, and a discussion of the formation and evolution of our sun based on Hubble and Webb images of stars as they are forming. I go into detail about the interior of our sun and how it creates its magnetic fields on the surface. This is the year of the April 2024 total solar eclipse so I cover the shape and origin of the beautful solar corona, too. You will be an expert among your friends when the 2024 eclipse happens.

Unlike all other books, I also have a chapter about how teachers can use this information as part of their standards-based curriculum using the NASA Framework for Heliospheric Education. I even have a section about why our textbooks are typically 10 – 50 years out of date when discussinbg the sun.

For the amateur scientists and hobbyists among you, there is an entire chapter on how to build your own magnetometers for under $50 that will let you monitor how our planet is responsing to solar storms, which will become very common during the next few years.

Basic book details: 239 pages; 115 ilustrations; 6 tables; 70,000 words;

There hasn’t been a book like this in over a decade, so it is crammed with many new discoveries about our sun during the 21st century. Most books for the general public about the sun have actually been written in a style appropriate to college or even graduate students.

My book is designed to be understandable by my grandmother!

Generally, books on science do not sell very well, so this book is definitely written without much expectation for financial return on the effort. Most authors of popular science books make less than $500 in royalties. For those of you that do decide to get a copy, I think it will be a pleasurable experience in learning some remarkable things about our very own star! Please do remember to give a review of the book on the Amazon page. That would be a big help.

Yep…I want to get the e-book version ($5): Link to Amazon.

Yep…I want to get the paperback version ($15): Link to Amazon.

Oh…by the way…. I am a professional astronomer who has been working at NASA doing research, but also education and public outreach for over 20 years. Although I have published a number of books through brick-and-morter publishing houses, I love the immediacy of self-publishing on topics I am excited about, and seeing the result presented to the public within a month or two from the time I get the topic idea. I don’t have to go through the lengthy (month-year) tedium of pitching an idea to several publishers who are generally looking for self-help and murder mysteries. Popular science is NOT a category that publishers want to support, so that leaves me with the self-publishing option.

Other books you might like:

Exploring Space Weather with DIY Magnetometers. ($7). Link to Amazon.

History of Space Weather: From Babylon to the 21st Century. (paperback, $30) (ebook, $5). Link to Amazon.

Solar Storms and their Human Impacts (e-book; $2) Link to Amazon.

The 23rd CycleL Learning to live with a stormy star. – Out of print.