BAN #175: Astro gifts, Cloudy Martian volcano

16 December 2019   Issue #175

December 16, 2019

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It’s that time of year once again, when the most common thing I am asked on Twitter is, “What kind of first-time telescope can I get for my cousin/nephew/niece/wife/husband/friend/kid/clone/?” That one’s easy: Go here and read what I wrote (and also this page by my friend Dr. Nicole Gugliucci).

Sometimes, though, people ask about other things with which I’m not as familiar, like books. Of course, I can think of one or two everyone should buy (and get multiple copies for cousins, nephews, nieces, etc. usw.). But if you want a book for kids, I can’t help you directly.

[Emily and me, at least the way Zach Weinersmith sees us.]

But my friend Emily Lakdawalla can! She’s a planetary scientist and terrific science communicator, and every year she goes through a pile of books to pick the best to recommend to people for just this occasion. Here’s her list for 2019. Emily is good people, and her list is sure to be the one you want. So take a look and save her answering her own FAQ tweet, at least this once.

And hey, if you’re looking for another gift idea, paid subscriptions to this here newsletter are available too!

Pic o’ the Letter

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

The Indian Space Research Organisation’s Mars Orbiter Mission has been orbiting the red planet since September of 2014. It was the country’s first mission to Mars, and has been an amazing success. The highly elliptical orbit takes the spacecraft from over 75,000 kilometers to a low of 420 km above the planet’s surface, so it can take detailed images as well as get an overview of the terrain (aresain?).

On 18 March 2018 it was swooping down over Olympus Mons, the enormous Martian volcano, the largest volcano on the planet and the tallest in the solar system. From a height of about 8,390 km it took this incredible image:

Wow! Kevin Gill reprocessed the original data, applying “tone, contrast, and sharpening algorithms” to produce this stunning shot. You can clearly see the caldera in the middle, and the cracked regions around it from lava that flowed eons ago. Most astonishing are the clouds circling the crater’s rim! The air of Mars is pretty thin and dry, but can form ice clouds under the right conditions (usually orographic uplift, when air is swept up the side of a mountain, or volcano in this case, and condenses).

For scale, the flank of the volcano (seen through the clouds as the bright ring of cliff around the caldera) is over 600 kilometers across, roughly the width of Arizona, and the summit is a staggering 21 km above the plains.

I love everything about this shot, especially the oblique angle that also shows the limb of Mars (the edge of the planet) off to the right. What scale!

Olympus Mons is big enough to see from Earth through a good telescope is seeing conditions are perfect. I have a bucket list of things in the sky I want to see with my own eyes, and this is one of them. Until then, well, I’m pretty happy with what spacecraft send us from being there.

For more images of clouds on Mars, see my posts here, here, and here (that last one has an animation of them moving!).

Blog Jam

What I’ve recently written on the blog, ICYMI

[Oops. From Wednesday’s article. Credit: Jingchuan Yu / Beijing Planetarium (modified by Phil Plait)]

Thursday 12 December, 2019: Ryugu’s history has been… weird

Friday 13 December, 2019: Flyby video of a Martian moon

Et alia

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