Month: October 2021

A smidge over 100 years ago, from the 13th to the 15th of May 1921, Earth received its worst gut punch from the sun in the 20th century. Many people are familiar with the Carrington Event of 1859 – our first real interaction with solar storms and coronal mass ejections – but few know about the 1921 event, which is considered almost as severe. Places like the Stockholm Telephone Switchboard, pictured below, were on the receiving end of hundreds of volts of electricity as their telephone wires got a charge induced on them by Earth’s rapidly changing magnetic field.

The exchange in Karlstad, about 150 miles to the west, caught fire and had to be evacuated. Train service coming into and out of Grand Central Station in New York was disrupted, as the voltage on the railroad lines prevented communications with the signaling equipment. Trains had to be guided in manually.

The cause? A one-two-three ejection from the sun known as a “Coronal Mass Ejection”: the first and third were big punches, but the second one was enormous. The sun belched millions of tons of charged particles right at Earth, three times in a row. The huge influx of solar radiation bent, twisted, and tortured the Earth’s magnetic fields – and the rapidly changing magnetic field induced a voltage on anything long and metallic … like a telephone cable or a railroad track. Depending on the location, up to ten volts of electric potential were generated in every kilometer of ungrounded wire. Telephone switchboard operators could be sitting on the wrong end of a 600 volt line.

Today, such a storm would wreak havoc on our intricate network of electrical and phone wires; we have 100x more wires strewn around now than we did in 1921, and the Western World is faaaar more dependent on electricity than it was 100 years ago. The intensity of the storm was measured at -900 nanoTeslas; the solar storm of 1989 (the most significant one in ‘recent memory’) was only -589 nanoTeslas.

We are not prepared.

The Gravity Probe B satellite … probably the most precise measurement you’ve never heard of.

In 1918, 2 years after Einstein unveiled his theory of General Relativity, two Austrian physicists (Josef Lense and Hans Thirring) noticed an intriguing side effect: Einstein’s equations predicted that large, spinning bodies (like Earth) should actually drag spacetime with them as they spun. It wasn’t until GP-B came along, 86 years later and 44 years after the experiment was first proposed, that frame-dragging could actually be measured.

The frame dragging effect, even after spending a year in Earth orbit 400 miles up, is tiny: it’s like measuring the width of a human hair from a quarter mile away. How do you do that? With four of the roundest objects ever made by mankind: the superconducting niobium coated fused quartz spheres. Second to neutron stars, these are probably the roundest objects in the universe.

Spun at 4,000 RPMs, these things became the world’s best gyroscopes (a million times better than navigational systems) and Did. Not. Move. The satellite pointed itself at a faraway star, spun up the gyroscopes, and watched as spacetime stretched underneath it by the slightest of degrees as the gyroscopes stayed in their original orientation.

There was a problem, however. There were “hot spots” (my term) where some charge would build up on the spheres and on the sphere housing. These hot spots would randomly cause a torque that would jerk the sphere left or right – only by a tiny amount, but even that tiny amount was a hundred times greater than the effect they were looking for. The team spent a frenzied 18 months trying to analytically account for these random jumps of the spheres. They could never reduce all of them.

Why the “B” in Gravity Probe B? Because Gravity Probe A was launched in 1976, and measured how time goes slower close to a massive object like Earth. GP-A went about 6,200 miles straight up, and confirmed that up there, clocks run about 4 parts in 10 billion faster – just like Einstein said they would.

If you want to dive waaaay down the rabbit hole of information, there is a technical journal called “Classical and Quantum Gravity” that devoted an entire issue to Gravity Probe B. You can find a great summary and all of the technical papers on their website.

For a slightly more digestible summary, Stanford has a good writeup with lots of pictures. Happy reading.

I’ve had these icons on my desktop for about three years now…

See the “Kindle Create” and the “calibre” icons? Kindle Create is Amazon’s tool for making ebook format files out of your Word document file. Calibre is the open source version of the same.

Although I did some fiddling around in Calibre, I ultimately chickened out and went with Kindle Create. Calibre offers a few more bells and whistles and more formatting choices, but I just saw those as a risk: the bells and whistles just made it more likely that I would get it WRONG and it wouldn’t work across ebook formats.

Formatting an ebook from a properly formatted Word file is pretty easy, once you know what to do (I learned that one the hard way with Skywriting in 2013). Formatting a book for print is an utter pain in the ass, but the advantage is that, after you’ve done all the typesetting, pagination, margin control, headers, and page numbers, you submit a PDF document to Amazon — so you know exactly what the book is going to look like. I find that reassuring.

The book is technically available for pre-order now, but I’m not fully advertising it yet because I’m still waiting for the cover art to come back. When I have THAT in hand, I’ll feel better about advertising and marketing … and revealing the title.