BAN #177: Special discount for the newsletter, Plato on the Moon

23 December 2019   Issue #177

[Saturn image credit: NASA / JPL / Space Science Institute / Gordan Ugarkovic]

Subscribers are the Moon to my Earth.

About this newsletter

Ooo, meta

Hey folks! The majority of you reading these words right now are free subscribers to my Bad Astronomy Newsletter, and I thank you for it!

The free issue goes out every Monday. On Thursday I also send out another issue to paid subscribers that has more content, and sometimes special content (more personal stuff, opinions, extra astronomy, and the like).

Normally, the subscription rate is $5/month or $50/year. However, ‘tis the season and all that… and of course by that I mean that Earth is approaching perihelion, the closest it gets to the Sun in its elliptical orbit. That occurs on 5 January 2020, so from right this moment until that day, I have dropped the subscription rate to a special price of $40/year, a 20% discount!

You can just click here to get the special annual rate. It’ll be good for a whole orbit around the Sun — well, a calendar year. Close enough.

If you don’t want to get a whole year, but just a month to try it out, that’s cool too.

You can also give someone else a gift subscription, too! It makes a fine last-minute holiday gift, IIDSSM.

Thanks! Paid subscriptions help me do things like pay for health insurance, feed my family, stay alive, etc. So I sincerely appreciate it.

Pic o’ the Letter

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

Damian Peach is well known for taking ridiculously gorgeous images of planets like Jupiter and Saturn, but it’s rare for him to take on our nearest cosmic neighbor, the Moon.

But when he does, of course it’s incredible. Of course it is.

[Credit: Damian Peach]

Whoa. Yeah, you super duper want to see that full size.

Plato is an impact crater on the Moon, about 100 km across. It’s over three billion years old, and its most striking feature is the floor, which doesn’t look like other craters. I’m sure it did after it formed, creating a bowl-shaped depression and a central peak, but at some point after that it got flooded with lava, so now its floor is really smooth. There aren’t many craters in it (at least not on this scale), indicating relative youth, so the flooding must have happened long after the crater itself formed.

It sits on the north edge of the huge Mare Imbrium, and even at a latitude of 50°, making it foreshortened into an ellipse, it’s really obvious even in binoculars.

But wait! There’s more! He also posted an image of the crater Copernicus:

[Credit: Damian Peach]

Whoa again. Copernicus is on the eastern edge of the truly huge Oceanus Procellarum, a vast flooded plain on the Moon’s west side. The crater is a little smaller than Plato, and looks more like a “normal” crater. It’s much brighter than Plato, too, indicating youth, and has an extensive set of rays radiating away from it, debris plumes blown out by the impact, making it obvious by binoculars, too.

Another master of his craft, Seán Doran, took Lunar Reconnaissance Orbiter images of Copernicus and made this amazing flyover of it:

I know social media is a plague upon humanity, but without it I would never have seen these images and video, so it’s not 100% garbage.

And when it’s good, well, oh my is it ever good. Follow Peach here, and Doran here.

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Blog Jam

What I’ve recently written on the blog, ICYMI

[A thermal infrared image of Jupiter’s south pole in November 2019 reveals six cyclones surrounding a central cyclone. From Monday’s article. Credit: NASA/JPL-Caltech/SwRI/ASI/INAF/JIRAM ]

Monday 16 December, 2019: Jupiter is still *really* weird: A new monster storm has formed around its south pole

Tuesday 17 December, 2019: A billion years ago the Milky Way had a huge burst of star birth

Wednesday 18 December, 2019: Across the Universe, it's the normal galaxies doing all the star-making work

Thursday 19 December, 2019: Are galactic spiral arms traffic jams or do they wind up? The evidence is… polarizing.

Friday 20 December, 2019: When galaxies collide, you get… a heron?

Et alia

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