What the heck is the “speed of light?” Part 1

Posted on June 7, 2023 by skullsinthestars

Most of us have heard a statement similar to the one that follows: “The speed of light is constant.” That particular phrasing of the statement comes from none other than the American Museum of Natural History’s Einstein exhibit, so I think it is fair to say that most people have heard it phrased in this way at one time or another.

Most physicists would add one very important caveat to this statement to reduce confusion: “The speed of light is constant in vacuum.” It is in this sense that it forms part of the foundation of Einstein’s special theory of relativity: any observer measuring the speed of a light wave traveling in vacuum will measure exactly the same result, about 186,000 miles per second or 300,000,000 meters per second, usually labeled c in physics. Different observers moving relative to one another will agree that a given light wave is moving at c, even if one is moving towards the light source and one is moving away from the light source! This is in contradiction to our day-to-day intuition: if I am driving towards a car that is approaching me, it will move towards me faster than if I am driving away from it.

From Einstein’s special theory of relativity, and the observation that “the speed of light is constant in vacuum,” comes all sorts of non-intuitive phenomena, like length contraction and time dilation and the idea that, as far as we know, nothing can move faster than c! Apparently the “speed of light” is the speed limit of the universe.

The statement “the speed of light is constant” is therefore arguably more accurate than not, but leaves out a lot of subtlety in discussions of the speed of light! I recently started thinking about the speed of light from an optical science perspective due to a question from a Twitter friend, and I thought I would muse a bit on all the ways that the speed of light is harder to define than you might think, even without talking about objects in relative motion.

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Posted in Optics, Physics | 2 Comments

Michael Faraday, grand unified theorist? (1851)

Posted on June 6, 2023 by skullsinthestars

While I’m working on a new optics blog post, here’s a classic post about Michael Faraday and gravity!

skullsinthestars's avatarSkulls in the Stars

At long last, I get to blog about the paper that first piqued my interest about the research of Michael Faraday!  If you haven’t been following my Faraday posts, let me give a quick recap: Michael Faraday (1791-1867) was one of the greatest experimental physicists of all time, and the discoverer of some of the most important effects related to electricity and magnetism.  I’ve blogged previously about his discovery of electromagnetic induction, his work in proving that all forms of electricity have the same common origin, and his demonstration of the relationship between light and magnetism (Faraday rotation). I haven’t even had time to discuss Faraday’s contributions in formulating the laws of electrolysis, understanding diamagnetism, and inventing the Faraday cage.

The common thread of many of these discoveries is their goal: demonstrating that all the physical forces of nature are but different manifestations of a…

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Old School Dungeons & Dragons: Part 31

Posted on June 5, 2023 by skullsinthestars

This is the 31st installment of old school Dungeons & Dragons! There’s nothing special about that milestone, other than me realizing that it’s a lot of posts. Anyway, let’s jump right to it…

X6: Quagmire! (1984), by Merle M. Rasmussen. Here we delve into one of the more obscure members of the E(X)pert series of modules!

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Night of the Big Heat, by John Lymington

Posted on June 4, 2023 by skullsinthestars

I don’t know exactly what first drew my attention to Night of the Big Heat (1959), by John Lymington. I suspect I was browsing through some Wikipedia posts about alien invasion movies, and caught sight of the 1967 film adaptation of the book, which starred none other than Christopher Lee and Peter Cushing, and that drew me to the novel. In any case, I bought a copy well over a year ago and just now finally decided to give it a look!

I really didn’t have high hopes for it when I read it, but this alien invasion story is surprisingly fun, and filled with clever ideas!

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The Dark Host, by Archie Roy

Posted on June 3, 2023 by skullsinthestars

Let’s take a look at one of the most obscure books I’ve ever read!

So, I’ve written about the work of Archie Roy before, in particular his novel Devil in the Darkness (1978), a remarkably good haunted house story. In fact, I wrote the introduction for the Valancourt Books edition of the novel, and discussed the remarkable career of Roy, who was not only a novelist but an astronomer and paranormal researcher!

With this in mind, a few months back I decided to track down another Archie Roy novel, and went with the one he wrote just before Devil in the Darkness, titled The Dark Host (1976).

The Dark Host is an unusual thriller, and not a supernatural one, but it definitely has a very macabre twist in it! I enjoyed it greatly, though maybe not for the reasons one would expect!

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Posted in Mystery/thriller | 2 Comments

Some book news!

Posted on June 2, 2023 by skullsinthestars

First of all, I got news that The New York Times may be running the review of my book on Invisibility in the Sunday, June 4th issue! Previously, the review appeared online way back in mid-April. This hasn’t been officially confirmed yet, as far as I know, but I’ll definitely be hunting for a copy on Sunday to see!

Also, just to keep a record of it here, I also did a short segment on CKNW radio in Vancouver yesterday to talk about invisibility! It was a ten minute segment, and I was on my phone doing it, but it was fun — thanks to CKNW for having me on! It turns out that, at least for now, you can hear the bit by going to CKNW’s audio vault and going to June 1, 6:00 am; the segment I’m on starts about 6 minutes in, with Genesis’ “Invisible Touch.”

Also: I totally forgot to share this when it happened, but the first copies of my book arrived on March 6th, 2023, and I made a short unboxing video at the time!

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Optics basics: thin films

Posted on June 1, 2023 by skullsinthestars

Color can have surprising origins in nature. Most of the time, the color of an object is dictated by the light it absorbs: for example, if you see an object that is blue, that means that it reflects all the blue light shining on it and absorbs all the colors that aren’t blue. But colors can arise from completely different phenomena: rainbows, for example, arise due to the phenomenon of dispersion, i.e. that different colors of light are refracted differently within a raindrop.

Then we have the not-quite-a-rainbow spectrum of colors that one sees when oil is spread out over the surface of water, such as this photo that I took a few months ago in my neighborhood:

These arise from a completely different effect: wave interference! The oil forms a thin layer on top of the water, and wave interference from the oil-air interface and the oil-water interface can produce constructive interference for colors, depending on the thickness of the oil layer.

Oil slicks are an example of what is generally known as thin film optics, in which unusual optical effects are produced by putting one or more thin layers of material, usually comparable to the wavelength of light, onto a base layer. This is not only a phenomenon seen “in the wild,” in things like oil slicks, but is practically used in optical design and engineering!

Let’s take a basic look at thin film optics and how it can produce bright colors on reflection — or suppress them entirely.

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Posted in Optics basics | 5 Comments

“Invisibility” on the Colin McEnroe Show!

Posted on May 31, 2023 by skullsinthestars

I get to share another interview that I did about invisibility today, this time live on the Colin McEnroe Show on WNPR in Connecticut!

It was a great conversation! It started with me talking about the science of invisibility, and then we were joined by Lisa Yaszek (Regents Professor of Science Fiction Studies in the School of Literature, Media, and Communication at Georgia Tech) to talk about invisibility in science fiction, and then we were joined by Sophia Brueckner (Futurist artist, designer and engineer, Associate Professor at the School of Art and Design, and Co-Director of the Center for Ethics, Society, and Computing at the University of Michigan) to talk about the ethics of invisibility, if it ever becomes a practical technology!

I actually learned a lot from the discussions with Professor Yaszek and Professor Brueckner, and they gave me new things to think about in the way I think about invisibility!

Anyway, please check it out, and thanks to Colin McEnroe and Lily Tyson for having me on the show!

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A short musical interlude…

Posted on May 30, 2023 by skullsinthestars

I’m still working on posting something to the blog every day for a certain number of days! Tonight, I’m a little exhausted and don’t have a lot of time to finish a new optics post, so I thought I’d share a couple of videos of me practicing classical guitar. This is partly for me as well as the audience — I need a lot more practice in front of a camera, as I always play worse when I am aware of an audience or recording!

This is an Allegretto by Matteo Carcassi that I happen to like and isn’t too difficult.

(Dedicating this performance to my friend Hannah.)

More science to come! And probably more guitar, too.

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The Little Black Bag, by C.M. Kornbluth

Posted on May 29, 2023 by skullsinthestars

As long as I’ve been having fun tracking down classic science fiction stories that I absolutely love, let me share at least one more! “The Little Black Bag,” by C.M. Kornbluth, first appeared in the July 1950 issue of Astounding Science Fiction. (You can read it on the Archive at this link.)

Cyril M. Kornbluth is one of my favorite science fiction authors, and largely due to three stories, that encapsulate a truly prescient view of the future and an extremely cynical one. In his story “The Silly Season” (1950), strange and nonsensical events worldwide that take up the attention of the newspapers turn out to be a distraction for an alien invasion. This story really anticipates the “noise chambers” that a lot of media companies have become, harping on nonsense issues to distract from serious ones. In his story “The Only Thing We Learn” (1949), a teacher recounts to students the heroic origins of their civilized society, whereas flashbacks show us the horror and brutality that those founders actually achieved. This story warns against the whitewashing of our history, while cynically suggesting that it will repeat itself with another conqueror.

The third story is “The Little Black Bag.” (Severe spoilers from here on out, so please read it first from the link.)

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Posted in Science fiction | 3 Comments