BAN #259: Meet Wanda!, Gorgeous Mars dunes

05 October 2020   Issue #259

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

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Personal Stuff

Yeah, but not too personal

Meet Wanda!

[Wanda and me, not necessarily in that order. Credit: Phil Plait]

Wanda is, for those of you not paying close attention, a horse. She joins the herd of our other two, Tasha and Tiny Elvis.

My wife loves horses, and when we moved out into the country the house we got had a barn, corral, and pasture ready to go. We didn’t use them much for a while (the goats were out there at first until we made a pen and shed for them closer to the house), but Marcella really wanted to ride. So she went to Colorado Horse Rescue and found some good candidates.

We went back and forth on some; we had a male we named Captain America (that was almost what we named one of the goats, until I decided I wanted to call him Jack Burton instead) but he was not a good fit. By the time we realized this we had already picked up Tasha — in fact I named her that for Natasha Romanoff, given the name of the other horse and that fact that she has red hair.

But then we sent Cappy back. You can’t have just one horse; like goats they’re herd animals and need to be around other horses. That’s when Marcella found Tiny Elvis (she came up with the name, and it’s perfect, especially since he’s a mini and he has a pouf of hair and mutton chops).

She can’t ride Tiny E for obvious reasons (like, he’s less than a meter high at the shoulder), and Tasha wound up having a bad leg after a year or so. The pandemic has made it hard to find horses, but by coincidence someone we know who works with horses had one that was perfect for us, so we took her in. Her name was originally Oakley, which is cute, but didn’t work for us. My daughter suggested we call her Scarlett, which I thought would be funny given who plays Romanoff in the movies, but then I came up with Wanda, for the Scarlet Witch, the MCU’s most powerful superhero (but again also due to red hair). Marcella loved it, so Wanda she is.

Wanda looks a lot like Tasha but doesn’t have the white blaze on her nose. As it stands right now the horses are getting used to each other; we keep Wanda separate for now. Tasha is used to have Tiny Elvis to herself, and doesn’t much like having a younger, healthier mare show up, so we’re watching them carefully. Horse politics are pretty easy to discern once you’ve seen them in action, and when Tasha settles a bit we’ll let them all be together all the time.

So, the new horse can run.
October 3, 2020

[Video of Wanda running; you might have to click it or right-click and open in a new window to get it to play. Credit: Phil Plait]

She’s still figuring things out, and we’re helping her adjust. Hopefully soon they’ll be one big happy herd. Marcella will be able to ride again, and I might ride her a bit as well before it gets too cold here, too.

As someone from the suburbs of DC I never thought I’d enjoy horses, but here we are. They’re big and smelly and can be real jerks, but they’re also pretty cool, and fun, and their strong personalities are worthy of respect.

Pic o’ the Letter

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

I love shots of dunes on Mars from orbit. Love love love. Especially when the way the individual shots are put together show the dunes as being very dark. They are dark, but when done this way they look like polished metal.

I mean, look:

[Credits: ESA/ExoMars/CaSSIS]


Dunes on Mars are typically made of volcanic basalt, which is a pretty dark rock. Erosion wears the rock down into grains, small enough that the extremely weak winds on Mars can push them in to dunes, though the process can be excruciatingly slow.

That image shows a dune field in a small crater about 15 kilometers wide; that crater sits inside the much larger Green crater, which is nearly 200 km across. The dune field is partly in Green and flows into the smaller crater.

The rim wall is to the left. It looks a little odd because the image was taken when the ExoMars Trace Gas Orbiter was directly over the crater, so vertical relief is suppressed, making it difficult to get a feel for what you’re seeing. If I’m not mistaken, the smoother land to the left (north) is the floor of Green crater, and the sudden transition to gray/white ice is the smaller crater’s wall with debris flow channels running down it. The dunes start where the wall meets the floor.

I was wondering how accurate the colors are here, but couldn’t find much info about this particular shot (European missions tend not to have that data as easily accessible as NASA missions). It was taken by the Colour and Stereo Surface Imaging System, a camera that maps the surface of Mars at a resolution of about 5 meters per pixel. It has filters that allow it to take images in blue/green, red, infrared, and a wide-band spectral range from blue to near infrared.

I think it’s natural color, given how red the ground looks. Sometimes the images are posted with the colors “shifted”, by which I mean the infrared image is displayed as red, the red as green, and the blue/green displayed as blue. It makes basalt look very blue and the surface oddly white or gray. The colors here are certainly very saturated, though. It makes for a very dramatic scene.

You can read more about the Trace Gas Orbiter at the ESA page. It was designed to map out gases like methane in the atmosphere of Mars, which some missions have detected and others haven’t. It’s weird, and a mystery that I believe that is still not solved. Methane might be created naturally by geology, but here on Earth it’s produced mostly by life, so of course scientists would like very much to know where it’s coming from on Mars.

The Orbiter also has the CaSSIS camera to take data as well, which is helpful if it does see trace gases… but also, obviously, can create spectacular and lovely images, too.

Blog Jam

What I’ve recently written on the blog, ICYMI

[Combined Herschel, Spitzer, and SOFIA image of the Swan. From Friday’s article. Credit: NASA/SOFIA/Lim, De Buizer, & Radomski et al.; ESA/Herschel; NASA/JPL-Caltech]

Monday 21 September, 2020: For the first time, an aurora is seen around a comet

Tuesday 22 September, 2020: More liquid water found on — *under* — Mars!

Wednesday 23 September, 2020: What's the matter with the Universe? About 31%.

Thursday 24 September, 2020: Solar flares cause massive ripples in and under the Sun's surface

Friday 25 September, 2020: SOFIA and starbirth in the Swan

Et alia

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