Multicolored Mars
Mars looking pretty panchromatic, plus my book is one of the best of 2023 so far!

June 15, 2023 Issue #578
My book
This is about Under Alien Skies, isn’t it? Yes. Yes it is.
I am extremely pleased to let y’all know that Amazon chose my book, Under Alien Skies, as one of it’s Best Science Books of 2023 So Far. Given that 2023 is half over that’s very cool!
They even have a badge for it!
The magazine New Scientist just published a positive review of it, too. The pull quote from that:
“A terrific guide to our spectacular universe. . . . Plait is a skilled, resourceful and, on occasion, downright visionary guide to the far reaches of outer space.” — Simon Ings, New Scientist
In fact I have an article I wrote for New Scientist based on the book that’ll be online soon. I’ll link to it when it goes live.
The initial promotional period for the book is winding down (it came out in April) but I still have a couple of interviews coming up for it, and when they’re up I’ll let y’all know. I’m pretty proud of this book, and I’m glad to see so many folks enjoying it. If you want to read it (or listen to it; I narrated the audiobook version) I have links on the book page.
Pic o’ the Letter
A cool or lovely or mind-bending astronomical image/video with a description so you can grok it
Colors are tricky.
We say Mars is red, but it isn’t. Not really. It’s more reddish-orange, like rust. That’s no coincidence! It’s covered in extremely fine-grained dust that’s primarily composed of oxides of iron, aka rust. Rusty dust. On the Martian crust. And when there’s a blustery gust it must just bust.

Anyway, that’s what gives Mars its overall rusty appearance, but there are other components. A lot of the surface is made of volcanic basalt, which looks gray to the eye, but other minerals reflect different colors, just not as strongly as the dust does, so they’re more subtle.
However, if you have a spacecraft orbiting Mars equipped with a camera and a variety of filters, you can observe the planet at different wavelengths (aka colors) and then use a little photographic trickery to enhance them, you get a much different view.

Neat! In this shot the green and blue are enhanced, producing a somewhat less eye-aching portrait. The darker areas are dominated by basalt, making it look brown. The big slash across the middle is Valles Marineris, an immense crack in the crust — actually a series of huge cracks that together are longer and wider and deeper than the Grand Canyon by a huge amount. At 4,000 kilometers long — enough to stretch nearly across the entire continental US — it may have formed when the truly staggeringly ginormous volcanoes to its west built up. The crust stretched and cracked, creating the valley.
Valles Marineris looks bluish in this enhanced image, likely due to clouds or fog lying in it. They’re thin, but ramping up the blue light in the image brings them out.
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