Bad Astronomy Newsletter #9

May 14, 2018 Issue #9

If you don’t subscribe then I will make the Sun turn into a red giant and fry the Earth. Caveat: It may take me a while.

Upcoming Appearances

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

June 3, 2018: I am very excited to let y’all know I’ll be giving a TEDxBoulder talk in June! The theme for the evening is Truth and Daring, and I’ll be talking about how science seeks truth, but we have to be daring to admit when our ideas don’t pan out. If you’re in the area tickets are going fast! But I’m sure there will be video of the talks. This is my second TEDx talk; the first was on asteroid impacts and you can watch that on the main TED site.

July 5 – 8, 2018: I’ll be speaking at SpaceFest IX in Tucson, AZ.

July 11 – 14, 2018: I’m speaking at ALCON, the Astronomical League Convention, in St. Paul, Minnesota. I have more on this and SpaceFest in Issue 1.

Science Getaways opening

My wife and I run a science vacation company called Science Getaways, where we take a vacation you’d want to go on anyway and add SCIENCE. We just had a couple of openings pop up in the next getaway, which is June 10 - 16, 2018 at Latigo Ranch in the mountains of Colorado. This is a beautiful dude ranch with spectacular views and great food. There’ll be horseback riding, hiking, science talks, and hanging out with good folks who share a love of science. That area also has very dark skies; I can’t wait to get my ‘scope under them and show y’all the heavens!

You can read about this trip at the Science Getaways site, and if you’re interested please email Marcella at

[One view from Latigo Ranch. I mean, if you like this kind of thing. Credit: Phil Plait.]

Pic o’ the Letter

A cool or lovely or mind-bending astronomical image/video with a short description so you can grok it

Pareidolia is the psychological tendency to see familiar shapes in random or semi-random patterns of objects. The most obvious example is seeing faces in clouds, for example.

Astronomical images are a wonderful playground of pareidolia because so many of the forces that sculpt objects on the trillion (or quadrillion)-kilometer-scale tend to push them into shapes we recognize. Check this one out:

[Credit: ESA/Gaia/DPAC]

See the cat? It’s facing left, with two big pointy ears. Or maybe it’s facing right and it’s actually a dog/fox/canine of some sort. The bright spot is one eye with ears above it, there’s a long snout, an open mouth, and the body stretches out to the left. It looks like it’s either leaping or lounging, depending on your own pareidolic leanings. 

What you’re seeing isn’t exactly an image. The European Space Agency satellite Gaia scanned the sky and has mapped the positions of about a billion stars. This image isn’t so much a photo of the sky as it is a map of the density of stars in a region in Orion. Literally, those aren’t stars, but where the image is brighter there are more stars squeezed together and where it’s darker there are fewer.

Orion is in the plane of the galaxy, so we’re looking into a volume of space loaded with stars. But there’s dust, too, which absorbs light from stars behind it, blocking them from our view. The “cat/canine” is actually a dark cloud, and the “eye” a cluster of young stars.

Gaia also measures the motions of stars, and has catalogued over two million velocities so far. This is critical to a lot of studies in astronomy, including our own motion through space, how clusters of stars move, and which stars are nearby. It’s a massive undertaking, but one with equally massive utility.

Even if it’s just to have a little feline fun. 

Blog Jam

What I’ve recently written on the blog, ICYMI

Monday, May 7: My god. It *is* full of stars 

Tuesday, May 8: The dead star, the doomed star, and their little friend

Wednesday, May 9: Neighbula

Thursday, May 10: Want to save the world? Vote.

Friday, May 11: Plaitgiarism

Follow o’ the Letter

Someone you should follow on social media

If you follow me on Twitter you’re probably already familiar with my friend Emily Lakdawalla. She has degrees in planetary geology and is a wonderful science communicator who writes extensively for The Planetary Society. Whenever she posts there it’s a must-read for me; she has a great way of explaining things in a way that’s understandable but not overly simplified.

[I only seem to have two pictures of Emily and me together, and one of them is this one drawn by SMBC’s Zach Weinersmith. Yes, we can actually do this.]

She also gives talks and has written on how to plumb astronomical databases for images and combine them into pictures, which is something I encourage people to try. It’s fun! You can find out more about her on her Wikipedia page, and you can follow her on Twitter.

And hey, look, her new book on the design and engineering of the Curiosity rover is now out! You can buy a copy on Amazon (affiliate link). She has a book excerpt available online you can read, too.

Et alia

You can email me at (I will reply… eventually), and all my social media outlets are gathered together at Also, if you don’t already, please subscribe to this newsletter! And feel free to tell a friend or ten, too. Thanks!