Einstein’s Eclipse

March 26, 2021: On May 29, 1919, the Moon slid in front of the sun and forever altered our understanding of spacetime. It was “Einstein’s Eclipse.” Using the newly-developed theory of relativity, the young German physicist predicted that the sun’s gravity should bend starlight–an effect which could be seen only during a total eclipse. Some of the greatest astronomers of the age rushed to check his prediction.

More than 100 years later, Petr Horálek (ESO Photo Ambassador, Institute of Physics in Opava) and Miloslav Druckmüller (Brno University of Technology) have just released a stunning restoration of the photo that proved Einstein right:

The original picture was taken in May 1919 by astronomers Andrew Crommelin and Charles Rundle Davidson, who traveled from the Greenwich Observatory in London to the path of totality in Sobral, Brazil. They were part of a global expedition organized in part by Sir Arthur Eddington, who wanted to test Einstein’s strange ideas. Glass photographic plates from the expedition were typical of early 20th century astrophotography, colorless and a little dull.

“Our restoration shows how the eclipse would have been recorded today–a magnificent sight,” says Horálek. “The astronomers in Brazil must have been amazed when they saw the giant prominence with their unaided eyes.”

Above: From the report of Sir Arthur Eddington, a half-tone reproduction of one of the negatives taken with the 4-inch lens at Sobral, Brazil.

Horálek got the idea for this restoration in 2019 when he saw a partially restored image released by the ESO (European Southern Observatory) to celebrate the 100th anniversary of the eclipse. A scan of the original plate was provided by the Heidelberg Digitized Astronomical Plates project … and then the real work began.

“I started by manually removing scratches and specks of dust from the copied plate,” says Horálek. “There were dozens of them, and the whole process took about 50 hours of work.”

Next, Horálek applied Noise Adaptive Fuzzy Equalization (NAFE) software to sharpen the remaining details. NAFE was developed by Prof. Druckmüller to enhance images from NASA’s Solar Dynamics Observatory. It worked marvelously on the old eclipse, revealing delicate streamers and hints of a dipole structure in the sun’s corona.

Finally, he added color. “I created a palette to make the image as natural as possible. The sun’s corona is white because it is sunlight scattered by free electrons. The prominence has that special red color (H-alpha) which hydrogen makes in the sun’s atmosphere. Once these two colors were fixed, the dark-blue hue of the background sky emerged naturally. Voilà!–a modern view of Einstein’s eclipse.”

Meanwhile, back in 1919, the eclipse was a sensation. Eddington measured the positions of stars near the sun during the eclipse. (Two of them, 65 and 67 Tauri, may be found in the bottom right of the restoration.) They were displaced just as Einstein predicted. Spacetime really was a fabric that could be stretched.

The result was splashed across the front pages of most major newspapers. It made Einstein and his theory of general relativity world-famous. Einstein has been quoted as describing his reaction if general relativity had not been confirmed by Eddington and Dyson in 1919: “Then I would feel sorry for the dear Lord. The theory is correct anyway.”

“2021 is the 100th anniversary of Einstein’s Nobel Prize,” notes Horálek. “This photo is our way of paying tribute to his work.”

Full credit: ESO/Landessternwarte Heidelberg-Königstuhl/F. W. Dyson, A. S. Eddington, & C. Davidson, P. Horálek/Institute of Physics in Opava, M. Druckmüller.

The Great Québec Blackout

March 13, 2021: They call it “the day the sun brought darkness.” On March 13, 1989, a powerful coronal mass ejection (CME) hit Earth’s magnetic field. Ninety seconds later, the Hydro-Québec power grid failed. During the 9 hour blackout that followed, millions of Quebecois found themselves with no light or heat, wondering what was going on?

“It was the biggest geomagnetic storm of the Space Age,” says Dr. David Boteler, head of the Space Weather Group at Natural Resources Canada. “March 1989 has become the archetypal disturbance for understanding how solar activity can cause blackouts.”

Above: Sunspot 5395, source of the March 1989 solar storm. From “A 21st Century View of the March 1989 Magnetic Storm” by D. Boteler.

It seems hard to believe now, but in 1989 few people realized solar storms could bring down power grids. The warning bells had been ringing for more than a century, though. In Sept. 1859, a similar CME hit Earth’s magnetic field–the infamous “Carrington Event“–sparking a storm twice as strong as March 1989. Electrical currents surged through Victorian-era telegraph wires, in some cases causing sparks and setting telegraph offices on fire. These were the same kind of currents that would bring down Hydro-Québec.

“The March 1989 blackout was a wake-up call for our industry,” says Dr. Emanuel Bernabeu of PJM, a regional utility that coordinates the flow of electricity in 13 US states. “Now we take geomagnetically induced currents (GICs) very seriously.”

What are GICs? Freshman physics 101: When a magnetic field swings back and forth, electricity flows through conductors in the area. It’s called “magnetic induction.” Geomagnetic storms do this to Earth itself. The rock and soil of our planet can conduct electricity. So when a CME rattles Earth’s magnetic field, currents flow through the soil beneath our feet.

Above: Grey areas indicate regions of igneous rock where power grids are most vulnerable to geomagnetic storms.

Québec is especially vulnerable. The province sits on an expanse of Precambrian igneous rock that does a poor job conducting electricity. When the March 13th CME arrived, storm currents found a more attractive path in the high-voltage transmission lines of Hydro-Québec. Unusual frequencies (harmonics) began to flow through the lines, transformers overheated and circuit breakers tripped.

After darkness engulfed Quebec, bright auroras spread as far south as Florida, Texas, and Cuba. Reportedly, some onlookers thought they were witnessing a nuclear exchange. Others thought it had something to do with the space shuttle (STS-29), which remarkably launched on the same day. The astronauts were okay, although the shuttle did experience a mysterious problem with a fuel cell sensor that threatened to cut the mission short. NASA has never officially linked the sensor anomaly to the solar storm.

Much is still unknown about the March 1989 event. It occurred long before modern satellites were monitoring the sun 24/7. To piece together what happened, Boteler has sifted through old records of radio emissions, magnetograms, and other 80s-era data sources. He recently published a paper in the research journal Space Weather summarizing his findings — including a surprise:

“There were not one, but two CMEs,” he says.

The sunspot that hurled the CMEs toward Earth, region 5395, was one of the most active sunspot groups ever observed. In the days around the Quebec blackout it produced more than a dozen M- and X-class solar flares. Two of the explosions (an X4.5 on March 10th and an M7.3 on March 12th) targeted Earth with CMEs.

“The first CME cleared a path for the second CME, allowing it to strike with unusual force,” says Boteler. “The lights in Québec went out just minutes after it arrived.”

Above: Auroras over Pershore, England, during the March 13, 1989, geomagnetic storm. Credit: Geoffrey Morley.

Among space weather researchers, there has been a dawning awareness in recent years that great geomagnetic storms such as the Carrington Event of 1859 and The Great Railroad Storm of May 1921 are associated with double (or multiple) CMEs, one clearing the path for another. Boteler’s detective work shows that this is the case for March 1989 as well.

The March 1989 event kicked off a flurry of conferences and engineering studies designed to fortify grids. Emanuel Bernabeu’s job at PJM is largely a result of that “Québec epiphany.” He works to protect power grids from space weather — and he has some good news.

“We have made lots of progress,” he says. “In fact, if the 1989 storm happened again today, I believe Québec would not lose power. The modern grid is designed to withstand an extreme 1-in-100 year geomagnetic event. To put that in perspective, March 1989 was only a 1-in-40 or 50 year event–well within our design specs.”

Some of the improvements have come about by hardening equipment. For instance, Bernabeu says, “Utilities have upgraded their protection and control devices making them immune to type of harmonics that brought down Hydro-Québec. Some utilities have also installed series capacitor compensation, which blocks the flow of GICs.”

Other improvements involve operational awareness. “We receive NOAA’s space weather forecast in our control room, so we know when a storm is coming,” he says. “For severe storms, we declare ‘conservative operations.’ In a nutshell, this is a way for us to posture the system to better handle the effects of geomagnetic activity. For instance, operators can limit large power transfers across critical corridors, cancel outages of critical equipment and so on.”

The next Québec-level storm is just a matter of time. In fact, we could be overdue. But, if Bernabeu is correct, the sun won’t bring darkness, only light.

Additional reading:

A 21st Century View of the March 1989 Magnetic Storm” by David Boteler, head of the Space Weather Group at Natural Resources Canada.

Geomagnetically induced currents: Science, engineering, and applications readiness” by Antti Pulkkinen (NASA/GSFC), Emanuel Bernabeu (PJM) and many others.