BAN #167: Mercury brightens, Rabbit vanishes

18 November 2019   Issue #167

November 18, 2019

Subscribers leave but one track in the snow.

Pic o’ the Letter

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

In last Monday’s newsletter I posted a video of Mercury heading toward the Sun in prelude to the big transit. As it approached it got fainter, because from Earth we see Mercury as a thinner and thinner crescent as it gets nearer the Sun.

It occurred to me that a similar video taken after the event would show the reverse, which would also be fun! So, voilà!

Mercury appears to the right of the Sun, moving right, at the start of the video. As you can see, it gets brighter as it moves away, because now the crescent is getting thicker, like the very new Moon starts as a thin crescent, then gets thicker every night. You can’t see that physically here because the Solar And Heliospheric Observatory doesn’t have the resolution to see it, but it can certainly see it changing brightness.

The star it passes near the end is Zubenelgenubi, in Libra. It’s a visual double star, which is why it looks weird, though it’s actually a multiple system, with each star you see also orbiting along with fainter star you can’t (we call these spectroscopic binaries, ad I explain in the Binary Stars episode of Crash Course Astronomy). There may even be a fifth star there too!

So, if you’re an early riser, Mercury is now a morning star, and will continue to pull away from the Sun for the next few weeks. It orbits the Sun every 88 days, so very soon it’ll be on the far side of its orbit, pass the Sun, and become an evening star once again. I hope you get a chance to take a look! I’ve seen it many many times, and it’s amazing how fast it moves in the sky; you can see it’s motion over just a single day!

And don’t forget that Venus is low to the west after sunset right now, with Jupiter right next to it. From about 22 – 25 November they’ll be very close together  (they get about 1° apart on the 23rd), which will be quite pretty, Take a look!

And while I’m at it, REMINDER: There may be a meteor storm on the evening of Friday the 22nd. I wrote an article with the info you need to see it. I hope we all can watch this!

Red in Tooth and Claw

I live in rural Colorado, and we get nature here

My kitchen window faces roughly west, toward the mountains (I won’t lie to you, it’s one reason we bought this house; the view is phenomenal). There’s a line of power poles heading that direction, and one in particular is, apparently, a favorite spot for raptors to land and imperious survey their kingdoms. We’ve seen bald eagles there, osprey, and more.

[Credit: Phil Plait]

I though this one was a juvenile osprey, but my friend Rosemary set me straight: It’s a Red-tailed hawk (she said the dark belly band of feathers gives that away). I was a little disappointed, because Red-tails are everywhere here, and ospreys more uncommon, but c’mon. I can’t feel too bad. Look at that bird!

They do pretty well around here, obviously. We have Great Horned owls and lots of other apex bird predators, and I can’t tell you how many mice and rabbits live within a hundred meters of our house. I’d guess trillions. It seems that way.

Which means that a lot of them get et. Sometimes we see evidence:

[Credit: Phil Plait]

Note the rabbit tracks stop rather abruptly, and there appears to have been a kerfuffle at the end. I looked around for several meters but didn’t see anywhere the tracks started up again, so I can safely assume one of our raptors had a decent breakfast.

The other night we heard coyotes right outside our front door, too. We hear them pretty often, but holy yikes was this group close. They probably got a rabbit or two themselves. But that’s why we have a goat house where the ungulates get put away every night at sunset. They’re a little bit big for coyote meals, but not too big for them to try.

We don’t worry about the horses. Any coyote that’s dumb enough to go after them gets what it deserves. And any coyote that dumb would’ve long been culled from the genetics of the species, I’d wager. I’ve seen a horse kick, and that is not something a coyote would survive. There’s a reason you don’t walk around the back of a horse without letting it know you’re back there (you run a hand along their back as you walk around and even then you keep an eye on them). The phrase shattered ribs isn’t all that theoretical when you have horses.

Anyway, winter is here so everything’s changing along the local food chain. I’m not sure what we’ll see, but I expect the cycle will continue even if we can’t see it. But when I do, if I have my camera, I’ll be sure to show you.

Blog Jam

What I’ve recently written on the blog, ICYMI

[Artwork depicting a star shot out of the galaxy by a supermassive black hole. From Wednesday’s post. Credit: James Josephides (Swinburne Astronomy Productions) ]

Et alia

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