BAN #247: Perseverance Marsbound, Comet outbound, Pop song Soundbound

24 August 2020   Issue #247

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

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Space news

Space is big. That’s why we call it “space”

This is pretty cool: NASA has added the Perseverance Mars spacecraft to its Eyes on the Solar System site, meaning you can follow the mission as it makes its way to Mars! The site is cool; it loads up a 3D model of the solar system and you can pan, tilt, and move around to look at planets, moons, and various missions visiting them.

[The Mars 2020 Perseverance spacecraft on its way to Mars. Credit: NASA/JPL-Caltech]

It should be informative to follow Perseverance for a while. The path it’s taking is called a Hohmann transfer orbit, which is a special kind that takes the least amount of energy to get from point A to point B (so it saves on rocket fuel). The spacecraft makes a half-ellipse as it orbits the Sun, going from Earth’s orbit to that of Mars. It’s launched in the direction of Earth’s motion, moving at a tangent to the orbit, and arrives at Mars the same way. Over the next few months that’ll be pretty obvious in the spacecraft’s trajectory.

So check out the site and play with the simulation. It’s fun to fool around and see how things are laid out, and where all the space missions are right now.

Pic o’ the Letter

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

The comet C/2020 F3 NEOWISE is on its way out of the inner solar system, currently 200 or so million kilometers from Earth. When it passed us in late July from a distance of about 100 million kilometers it was easily visible to the naked eye, and I quite enjoyed the view through my 20-cm ‘scope.

Hubble is a bit bigger, and without an atmosphere to screw up the sight it’s in a somewhat better position to get good images.

And so it did:

[Comet NEOWISE via Hubble. Credit: NASA, ESA, Q. Zhang (California Institute of Technology), A. Pagan (STScI)]

Nice. The nucleus (the solid bit of rock and ice) is likely less than 5 kilometers wide, and buried in the coma, the gas surrounding it, so it can’t seen here — and would be far too small (by a factor of 20!) to be resolved even with Hubble’s keen eyesight at a distance of 150 million km, as it was on 8 August 2020 when this image was taken.

But it does look elongated, due to a pair of jets blowing material out of vents in the comet’s surface. As that gas and dust blows out it forms the bowtie structure you can see extending away.

[Comet NEOWISE wide view from the ground, showing where Hubble was looking to see the detail. Credit: NASA, ESA, Q. Zhang (California Institute of Technology), A. Pagan (STScI), and Z. Levay]

Sadly, NEOWISE is on such an elliptical orbit that it won’t be back for, oh, about 7,000 more years. So this is pretty much it for the comet. Happily, though, a comet like this passes Earth and becomes bright every few years, so hopefully we won’t have to wait too long for the next one.

Apropos of nothing

Not everything needs to be themed

For some reason, probably coincidence, the past three times I have been in my car I turned on the radio and the song “I Love You Always Forever” by Donna Lewis has come on.

Sure, you remember this song. It’s an impossibly catchy earworm pop hit from 1996, with Lewis breathily singing about how much she loves her partner, sounding like Cyndi Lauper but more winsome.

It’s weird that it keeps popping up when I happen to have the radio on in the car, but it does serve as a reminder that along with some of the lyrics being legitimately nice, there’s also this line:

“As we lay there under a blue sky with pure white stars”

… and apparently I am the only person on the planet who realizes that you can’t see pure white stars during the day and I feel like how did everyone involved with this song miss this and don’t give me any guff about it being shortly after sunset or whatever because only a few stars are out when the sky is by even a stretched definition “blue” and those stars tend to be blue like Vega or red/orange like Arcturus and Antares and if I had been involved with writing it I would’ve suggested changing it to “… under the twilight and shining stars” which still scans well and is scientifically closer to reality though it isn’t as romantic and likely wouldn’t have helped the song be the megahit it eventually became.

So that’s a peek inside my brain if you wanted it. Anyway here’s the song.

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Blog Jam

What I’ve recently written on the blog, ICYMI

[Artwork of stars orbiting the Milky Way’s central supermassive black hole, from Monday’s article. Credit: ESO/L. Calçada/spaceengine.org]

Monday 17 August, 2020: The fastest star in the galaxy has been found, and yeah, it’s really *really* fast

Tuesday 18 August, 2020: The mysterious spirals of RU Lupi

Wednesday 19 August, 2020: A small asteroid called 2020 QC just gave Earth the closest near-miss ever seen

Thursday 20 August, 2020: The *entire* sky glows from the light of distant hydrogen. All of it, everywhere.

Friday 21 August, 2020: The Orion Nebula like you’ve never seen it before

Et alia

You can email me at thebadastronomer@gmail.com (though replies can take a while), and all my social media outlets are gathered together at about.me. Also, if you don’t already, please subscribe to this newsletter! And feel free to tell a friend or nine, too. Thanks!