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Mark McCaughrean

@markmccaughrean

28 Jan

@ESASolarOrbiter

Cosmic detective story time 🕵️‍♂️🕵️‍♀️

Remember that @ESASolarOrbiter movie released yesterday, showing Venus, Earth, & Mars as the spacecraft cruised along last November? 🛰

Turns out there's a fourth planet in there: Uranus 🙂

The tale of how it was spotted is worth telling 👍

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@ESASolarOrbiter

@ESASolarOrbiter The original movie, made from 22 hours of images taken by the SoloHI instrument on #SolarOrbiter clearly showed Venus, Earth, & Mars moving against the stellar background as the spacecraft & planets moved on their orbits.

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https://twitter.com/ESASolarOrbiter/status/1354067873514344455

@ESASolarOrbiter

@ESASolarOrbiter The movie was posted in several places, including on the Facebook page of @RAL_Space_STFC, one of @esa's partners in the mission. In a comment on that post, James Thursa posed an interesting question. He asked whether Uranus was also in the image.

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facebook.com/pg/RAL.Space/p…

Read 21 tweets

Mark McCaughrean

@markmccaughrean

15 Oct 20

Before you get too excited about today's #BepiColomboVenusFlyby images, keep in mind that they will have been taken with the engineering cameras designed to confirm hardware deployments, not the main science camera.

Why & what does that mean?

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@bepicolombo

En-route to Mercury, @bepicolombo is a stack of three spacecraft: the propulsion module, @esa_mtm, the @esa orbiter, @esa_bepi, & the @jaxa_en orbiter, @jaxa_mmo. They only separate when we finally enter Mercury orbit in 2025.

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@BepiColombo

@BepiColombo @ESA_MTM @esa @ESA_Bepi @JAXA_en @JAXA_MMO Some of the science instruments, including the main science camera, SYMBIO-SYS, are sandwiched between the MTM & the European orbiter, MPO, at this stage, due to the way the MPO has been designed to work once the spacecraft reach Mercury.

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Read 23 tweets

Mark McCaughrean

@markmccaughrean

3 Jul 20

My talk on space astronomy & the impact of megaconstellations at #EASLeiden2020 today was recorded & it'll be best to hear the narration to make full sense of it. In lieu of having the recording to hand yet though, here at least are my slides to get some idea 🤷‍♂️

Thread: 1/

Slides from talk on space astronomy & the impact of megaconstellations for #EASLeiden2020.

cont.

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Slides from my talk on space astronomy & the impact of megaconstellations for #EASLeiden2020.

cont.

3/

Read 10 tweets

Mark McCaughrean

@markmccaughrean

26 Apr 20

Fascinating. I didn’t realise wild storks had been extinct in the UK for centuries – there are loads of them around us here in NL.

In particular, there is a large flock in The Hague & strangely enough, they don’t migrate in winter. 1/ theguardian.com/environment/20…

The reason is that storks were domesticated here in the Middle Ages & helped clean away fish remains at the fish market in the Binnenhof. So their ancestors stay here in the winter, instead of migrating to Africa. They’ve been on the coat of arms of Den Haag since 1541. 2/

There is a large flock in the north side of the The Hague & a lady calls them down off their nests atop the apartment buildings to feed them once a day – an impressive sight. I posted a movie of it, but can’t find it now. 3/

Read 5 tweets

Mark McCaughrean

@markmccaughrean

14 Jan 20

@esa

#OTD in 2005, @esa's Huygens probe descended to the surface of Titan as part of the @CassiniSaturn mission.

I wasn't working for ESA at the time, but happily took part in an inadvertent experiment in public engagement that took place that day.

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@esa

@esa @CassiniSaturn IIRC, as imaging data arrived back from Saturn, they were transferred from @esaoperations to the DISR camera team at @uarizona via ftp.

The ftp account was public & unpassworded, & details of its existence leaked on to the internet.

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@esa

@esa @CassiniSaturn @esaoperations @uarizona Like many, I went on to the ftp account & downloaded images as they arrived. They were raw & uncalibrated as below, & Huygens was spinning, so it wasn't clear (at least to my untrained eye) that they were showing valleys, channels, & flood plains.

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planetary.org/blogs/guest-bl…

Read 20 tweets

Mark McCaughrean

@markmccaughrean

24 Dec 19

There's a lot of discussion about the dimming of Betelgeuse on astrotwitter at the moment.

This simulation by Bernd Freytag et al. spanning just 16 years shows just how crazily variable red supergiant stars can be due to convection & magnetic fields.

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astro.uu.se/~bf/publicatio…

That 3D magnetohydrodynamical simulation using the CO5BOLD code is of a 5 solar mass star with a radius of 600 solar radii (IIRC – need to check) & shows roughly what you'd see with the naked eye. It's very red because red supergiants are cooler than the Sun, around 3500K. 2/

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Betelgeuse is larger, ~11–20 solar masses & 900 solar radii (630 million km, 80% of the distance between the Sun & Jupiter), but the same physics applies: huge convection cells from the core to the surface, with magnetic fields threading through, as seen here by Freytag et al. 3/