BAN #219: SEE me speed date, Throwing open Snell’s Window

18 May 2020   Issue #219

[Spiral Galaxy M81 image credit: Adam Block/Mount Lemmon SkyCenter/University of Arizona]


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Upcoming Appearances/Shameless Self-Promotion

Where I’ll be doing things you can watch and listen to or read about

The Science and Entertainment Exchange (or SEE) — an NAS-funded group that promotes better use of scientists and science in movies, TV shows, games, and more — does an event they call Science Speed Dating, where a panel of scientists have just a few minutes to describe the work they do. I was panelist at one they did in 2018 at San Diego Comic Con and it was pretty entertaining.

They’re holding another one, but given the time we live in, it will be virtual and you can watch live! All the info you need is here — but they don’t mention there that there will be commenters afterwards who will discuss the various things that struck them that the scientists said… and I’ll be one of ‘em! This should be a lot of fun, so I hope you watch!

For your edification, here’s the video of the one the SEE sponsored at SDCC in 2018. The MC is Eric Heisserer, who wrote the movies “Arrival” and “Birdbox”.



Blog Jam

What I’ve recently written on the blog, ICYMI

[A stunning photo of the star Betelgeuse, from Tuesday’s article. Credit: Adam Block /Steward Observatory/University of Arizona]

Monday 11 May, 2020: A huge black hole eats a huger black hole's dinner then explodes with the light of a trillion suns

Tuesday 12 May, 2020: B E T E L G E U S E

Wednesday 12 May, 2020: Chelyabinsk's (much) smaller sibling asteroid fell over Arizona in 2016

Thursday 13 May, 2020: Moonrise Mirage

Friday 14 May, 2020: Breathe easy: Pluto’s atmosphere is not about to collapse


Astro Tidbit

A brief synopsis of some interesting astronomy/science news that may be too short for the blog, too long for Twitter, but just right (and cool enough to talk about) for here.

Have you ever seen a picture taken from underwater looking up, and the sky above the water takes on a circular shape? You probably have and haven’t thought about it much; I know that’s true for me.

[Water distorts incoming light into a circle due to refraction and Snell’s Law. Credit: David K. Lynch and Simon Higton via EPOD.]

If someone had asked me why this happens, I probably would’ve eventually realized it’s due to refraction and Snell’s Law (named after the dude who figured it out): Light bends when it moves from one medium to the next. So when light passes from air to water, for example, it bends a bit, and vice-versa, and the amount it bends depends on the angle it comes in at. It’s why a spoon sitting a glass of water looks “broken”. I explain this in more detail in a blog post I wrote a while back.

[Light bends when it leaves water and enters air, causing images to look bent or broken. Credit: Phil Plait]

Anyway, I’m not sure I could explain the circle sky effect more than that without thinking much more carefully about it, but now I don’t have to: An article on the Earth Science Picture of the Day already does!

Basically, light coming in from the edges of the field of view of the camera gets bent downward as it enters the water, so from the camera’s point of view it’s as if that light is coming from closer to the center. The net effect is that the light coming from the edges gets scrunched together toward the middle of the photo, creating the circle. This even has a name: Snell’s Window. I love that.

Refraction is how lenses work, and plays into a lot of what we see around us without us even knowing it. I wrote the blog article I mentioned above as an intro to a great video about refraction by master astrophotographer Babak Tafreshi, and because why not, here it is. It’s really cool.

I read EPOD every time they publish (I use an RSS feed reader for that sort of thing) and it’s always a fun article. Check ‘em out.


Et alia

You can email me at thebadastronomer@gmail.com (though replies can take a while), and all my social media outlets are gathered together at about.me. Also, if you don’t already, please subscribe to this newsletter! And feel free to tell a friend or nine, too. Thanks!