Hey folks, I posted a new short history of science video on TikTok, telling a slightly eerie story in the spirit of Victorian Christmas ghost stories about the fate of astronomer Charles Delaunay.
This is another classic post that I will probably turn into a TikTok video in the future, but I am very proud of the writing I did here!
Just a short note to let people know that I’ve started experimenting with posting videos on TikTok about the weird history of science stories that I know! Will see how long I can put up with the effort!
For those interested, the link to my account is here, and the second video, about a particularly scary moment for a famous vulcanologist, is posted below.
I’m currently writing a textbook on Electromagnetic Waves for my graduate optics students. I was reading up on zero refractive index materials for a chapter section and thought it would be fun to write a popularized account of their fascinating and counterintuitive properties!
The past two decades have been a fascinating time to be an optics researcher. During that period, old rules about what light can and cannot do have been found in many cases to be more like guidelines, and ignoring those guidelines have led to some really astonishing new optical phenomena and devices.
One area where the rules have changed dramatically is in our understanding of the refractive index of light. The refractive index of a material, usually expressed in mathematical equations by the symbol n, represents the amount by which the speed of light is reduced in the medium from its vacuum value. If we label the speed of light in vacuum as c, then the speed of light in the medium is given by c/n. As an example, the refractive index of water in the visible light spectrum is roughly 1.33, which means that the speed of light in water is c/1.33, or 3/4ths the vacuum speed of light.
The most famous and most dramatic demonstration of seeming rule-breaking is the demonstration of materials with a negative index of refraction. When light travels from one medium to another, its direction changes according to the law of refraction, known as Snell’s law.
Mathematically, we write Snell’s law as
where “sin” represents the trigonometric sine function. This formula indicates that when light goes from a rare medium (low refractive index) to a dense medium (high refractive index), the light direction bends towards the perpendicular to the surface.
But what if the second medium has a negative index of refraction? Then Snell’s law would tell us that the light would bend on the opposite side of the perpendicular to the surface.
For centuries, this was assumed to be impossible, because among other things how could light have a negative speed? But in the 1960s, Russian physicist Victor Vesalago argued1 that there is nothing in physics that prohibits a negative refractive index, and further argued that a negative index material could be used to make a flat lens, as illustrated below.
Veselago’s work went largely unnoticed until, in 2000, UK physicist John Pendry noted2 that not only was Veselago’s lens possible, but it would in principle have perfect resolution, violating another long-held belief by optical scientists that imaging systems always have finite resolution.
Pendry’s result requires the fabrication of materials with optical properties that do not exist in nature, now called metamaterials. A metamaterial is a material that gets its optical properties from an artificial subwavelength-size structure. Many scientists initially scoffed at Pendry’s predictions, but materials with a negative refractive index3 were fabricated soon afterward, and rough experimental tests4 of the perfect lens prediction demonstrated that the principle is sound.
The introduction of negative refraction led physicists to ask: what other types of very unusual optical materials are possible, and what might they be used for? One obvious answer to the question was: we can make materials with a refractive index that is zero, or very close to zero! Such materials are known as “epsilon near zero” (ENZ) materials, and let’s take a look at what they can do.
Continue readingThought I’d share an old post from the physics archives, talking about a very important yet largely forgotten milestone in physics: the demonstration that X-rays are in fact another type of electromagnetic wave!
Okay, I finally decided that I needed to read Paperbacks from Hell, by Grady Hendrix, which was first published in 2017!
Back in October, I wrote about the 1984 horror novel Carnosaur, and it sent me fondly reminiscing about all the cheap paperback horror novels I read as a kid. I bought books like Crabs on the Rampage, about hordes of giant crabs, impervious to even tank cannons, rampaging across the UK.
Continue readingI have been rather distracted for a few months and haven’t had much time to do old school Dungeons & Dragons threads on social media, but I’m working my way back into the habit! Here’s a compilation of the four most recent threads I did about classic D&D products.
Dark Sun (1991), by Timothy B. Brown and Troy Denning. This is a big one: probably the most innovative and ambitious campaign setting that TSR introduced into Dungeons & Dragons, and one that also introduced innovative play mechanics.
I’ve been using my blog as a place to keep track of any mentions of my book on Invisibility: The History and Science of How Not to Be Seen, which came out early this year, and there’s one big review that I was unaware of that came out back in July! My book was reviewed in the Times Literary Supplement, a prestigious magazine with a century-old history!
Alas, one has to have a subscription to read the full review, but it is a really nice discussion of the book. I’ve been really delighted to see how much attention the book has gotten in the press.
And, of course, if you haven’t read it, check out the link in my blog post about it! Also, if you have read it, and enjoyed it, please consider leaving a review at the book site of your choice! (If you didn’t enjoy it, you can still leave a review, but I’m not gonna encourage you!)
Hi all, just a short note that if you weren’t aware, MST3k is fundraising for season 14, and there’s only a few hours left to make their goal and they’re quite short of the goal. If you were unaware that the fundraiser was going on (due to the writer’s strike and the collapse of social media as news), now’s your last chance to chip in!
MST3k is still a hilarious show, and started some 35 years ago! MST3k now has a permanent dedicated streaming home, the Gizmoplex, where you can either subscribe or rent shows on demand. Really hoping that they manage to pull off the new season!
As readers of the blog know, I’ve been on a Valancourt Books world horror kick recently (see here, here and here), as they’ve been releasing English translations of world horror authors, many of the stories and collections appearing in English for the first time. I recently picked up and read Orchard of the Dead, by Stefan Grabinski.
Unlike the other world horror collections I’ve looked at, this one is much older: Polish author Stefan Grabinski was born in 1887 and died in 1936, so his work was written in the same era as Lovecraft. He has in fact been referred to as the “Polish Lovecraft” or “Polish Poe,” though my reading of the stories suggests that the latter characterization is more accurate (and more complimentary).
Continue reading
The author of Skulls in the Stars is a professor of physics, specializing in optical science, at UNC Charlotte. The blog covers topics in physics and optics, the history of science, classic pulp fantasy and horror fiction, and the surprising intersections between these areas. 
Skulls in the Stars 