Dr. Raphael Marschall
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Dr. Raphael Marschall
@spacemarschall.net
4.1K followers 360 following 900 posts
#asteroids #comets #protoplanetarydisks #planetaryScience 🧪🔭🚀🛰️☄️
Science Programme Manager @issibern.ch. Co-I of ESA's Comet Interceptor, collaborator on NASA's Lucy and ESA's Rosetta missions.
www.spaceMarschall.net
(he/him)🇨🇭🇺🇸🇫🇷
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spacemarschall.net
Dr. Raphael Marschall @spacemarschall.net · Nov 14
Hello to all new followers! I'm a 🇨🇭 physicist and planetary scientist at the Observatory in Nice 🇫🇷. I study asteroids, comets, and similar bodies and how they formed/evolved. This helps us understand how our Solar System formed. I'm also involved in several space missions.
#planetaryScience 🔭🧪🚀🛰️☄️🪨
Family picture of all asteroids visited by spacecraft except for Ceres. The different asteroids are to scale with Vesta being over 500 km large to Itakawa at only 500 m. High resolution image here: https://spacemarschall.net/outreach/asteroid-family-picture/ Credit to individial asteroids in the legend.
Reposted by Dr. Raphael Marschall
adampknave.com
I've started to see arguments that we have to get used to AI Slop coding even if it isn't great, because it's fast. Humans could go faster, too, if they're allowed to turn in stuff that only sometimes works. Such a fascinating double standard that will in no way come back to haunt, naw.
December 26, 2025 at 5:10 PM
spacemarschall.net
It's Boxing Day, and we have the ultimate matchup: Uranus vs. Earth.

You can vote for your favourite image in this thread bsky.app/profile/spac...

Voting ends on Tuesday, Dec. 30, at 3 p.m. UTC/4 p.m. CET/10 a.m. EST/7 a.m. PST/midnight JST.
Dr. Raphael Marschall (@spacemarschall.net)
Final of ✨ #planetaryScience image of 2025 ✨ is here: Uranus vs. Earth or outer vs. inner Solar System 🗳️ The vote link is 3 posts down. Voting ends on Tuesday, Dec. 30, at 3 p.m. UTC/4 p.m. CET/10…
bsky.app
December 26, 2025 at 6:04 PM
spacemarschall.net
Final of ✨ #planetaryScience image of 2025 ✨ is here:

Uranus vs. Earth
or
outer vs. inner Solar System

🗳️ The vote link is 3 posts down. Voting ends on Tuesday, Dec. 30, at 3 p.m. UTC/4 p.m. CET/10 a.m. EST/7 a.m. PST/midnight JST. 🧪⚛️
Bracket for "BSky Planetary Science Image of 2025" contest, featuring small icons of 16 images grouped into four quarter-finals. Then there were two semi-finals and the filled in spots of the final with Uranus on the left and a lightning into the Earths atmosphere on the right. There are winner placeholders is still just a question mark. All is set on a lunar surface backdrop.
December 26, 2025 at 3:00 PM
spacemarschall.net
Click on the image name you want to be the image of the year:

1️⃣ Uranus as seen by JWST
2️⃣️ Gigantic TLE above Mexico seen from the ISS

📅 Ends: December 30, 2025, 3:00 PM UTC

📊 Show results
December 26, 2025 at 3:00 PM
Reposted by Dr. Raphael Marschall
astromikemerri.bsky.social
The thing about art is that it can be interpreted by the viewer as they wish, especially when the artist gives no comment. I choose to interpret the latest Banksy as a statement on the importance of astronomy… 🔭
December 23, 2025 at 9:09 AM
spacemarschall.net
🗳️ Currently, the image from Earth is cleaning the clock of one of comet Lemmon. If you are on #teamComet you'll have to step up and vote below ⬇️

Though I have to say that the one of the lightning seen from the ISS is quite spectacular!
spacemarschall.net Dr. Raphael Marschall @spacemarschall.net · 5d
2nd semi-final of ✨ #planetaryScience image of 2025✨
This round features Earth vs. Comets 🧪⚛️

🗳️ Voting ends on Wednesday, Dec. 24, at 3 p.m. UTC/4 p.m. CET/10 a.m. EST/7 a.m. PST/midnight JST.

Here are the two semi-finalists 🔽
Bracket for "BSky Planetary Science Image of 2025" contest, featuring small icons of 16 images grouped into four quarter-finals. There are finalist placeholders against a lunar surface backdrop.
December 22, 2025 at 4:24 PM
Reposted by Dr. Raphael Marschall
planetplanet.bsky.social
My new paper with Nate Kaib explores what triggered the dynamical instability that took place among the giant planets in the young Solar System.

We show that the flyby of a low-mass brown dwarf or free-floating planet could have done it (probability ~5%).

ui.adsabs.harvard.edu/abs/2025arXi...
December 22, 2025 at 12:21 PM
Reposted by Dr. Raphael Marschall
transport.esa.int
As you're preparing for 2026, don't forget to add the post-CM25 industry event to your calendars:

🗓️ 14 January 2026
📍 Online

@esa.int Director General @josefaschbacher.esa.int and all ESA directors will present the outcome of the ESA Council at Ministerial Level 2025.

www.esa.int/About_Us/Bus...
Post-CM25 industry event online set for 14 January
On 14 January 2026, the European Space Agency (ESA) will hold an online post-CM25 industry event for all ESA industrial partners.
www.esa.int
December 22, 2025 at 9:33 AM
spacemarschall.net
2nd semi-final of ✨ #planetaryScience image of 2025✨
This round features Earth vs. Comets 🧪⚛️

🗳️ Voting ends on Wednesday, Dec. 24, at 3 p.m. UTC/4 p.m. CET/10 a.m. EST/7 a.m. PST/midnight JST.

Here are the two semi-finalists 🔽
Bracket for "BSky Planetary Science Image of 2025" contest, featuring small icons of 16 images grouped into four quarter-finals. There are finalist placeholders against a lunar surface backdrop.
December 21, 2025 at 3:11 PM
spacemarschall.net
Click on the image name you want to see advance to the final:

1️⃣ Gigantic TLE above Mexico seen from the ISS
2️⃣️ Comet C/2025 A6 (Lemmon) and a meteor train

📅 Ends: December 24, 2025, 3:00 PM UTC

📊 Show results
December 21, 2025 at 3:11 PM
spacemarschall.net
🗳️ Four more hours to vote for your favourite semi-finalist (Mars vs. Uranus) for the Planetary Science Image of the Year. Vote link can be found in the thread here: bsky.app/profile/spac...

🧪 #SciComm #Mars #Uranus
Looking back over the rover's chassis (bottom-right) and dark parallel wheel tracks trailing back into the distance, where a dust devil - a tall narrow swirling cone of light dust and grit whipped up by thermal currents in the thin dusty air - plays across the ground in front of some low hills. Source: https://bsky.app/profile/martian-observer.art/post/3lqff6e45xs2j Credit: NASA/JPL-Caltech/MSSS/Martian-Observer @martian-observer.art Image of planet Uranus taken by the James Webb Space Telescope (JWST). Source: www.flickr.com/photos/192271236@N03/54879990600/sizes/o/ Credit: NASA/ESA/CSA/STScI/AndreaLuck CC BY Colourised image created processing data from: mast.stsci.edu NASA/ESA JWST Webb Space Telescope Instrument: NIRCAM Title: CAL-NRC-421: NIRCam Linearity Characterization Target: Uranus Time: 2025-10-06 Filters: F150W2-F162M, F410M Observation ID: jw08975-o001_t001_nircam_f150w2-f162m-sub320, jw08975-o001_t001_nircam_clear-f410m-sub320 Proposal PI: Varun Bajaj PI Institution: Space Telescope Science Institute Proposal ID: 8975 www.stsci.edu/jwst-program-info/program/?program=8975 Credit: NASA/ESA/CSA/STScI/AndreaLuck CC BY
December 21, 2025 at 11:13 AM
Reposted by Dr. Raphael Marschall
emily.space
Ever wondered how many bins to choose when making a histogram of data? The answer is that you shouldn't choose a number of bins yourself! ☄️ #astrocode

Here's a little notebook explaining how to make less biased histograms:
Making histograms is a common way to estimate the true density distribution of a sample. But how can we choose the number of histogram bins? And if we get fancy and use kernel density estimation (KDE)...
Making histograms is a common way to estimate the true density distribution of a sample. But how can we choose the number of histogram bins? And if we get fancy and use kernel density estimation (K...
gist.github.com
December 19, 2025 at 9:19 AM
spacemarschall.net
The first semi-final is super close (50%/50%) as of right now. Will Mars or Uranus reach the final? There is still time to vote in this thread: bsky.app/profile/spac...
Looking back over the rover's chassis (bottom-right) and dark parallel wheel tracks trailing back into the distance, where a dust devil - a tall narrow swirling cone of light dust and grit whipped up by thermal currents in the thin dusty air - plays across the ground in front of some low hills. Source: https://bsky.app/profile/martian-observer.art/post/3lqff6e45xs2j Image of planet Uranus taken by the James Webb Space Telescope (JWST). Source: www.flickr.com/photos/192271236@N03/54879990600/sizes/o/ Credit: NASA/ESA/CSA/STScI/AndreaLuck CC BY Colourised image created processing data from: mast.stsci.edu NASA/ESA JWST Webb Space Telescope Instrument: NIRCAM Title: CAL-NRC-421: NIRCam Linearity Characterization Target: Uranus Time: 2025-10-06 Filters: F150W2-F162M, F410M Observation ID: jw08975-o001_t001_nircam_f150w2-f162m-sub320, jw08975-o001_t001_nircam_clear-f410m-sub320 Proposal PI: Varun Bajaj PI Institution: Space Telescope Science Institute Proposal ID: 8975 www.stsci.edu/jwst-program-info/program/?program=8975 Credit: NASA/ESA/CSA/STScI/AndreaLuck CC BY
December 19, 2025 at 7:44 AM
spacemarschall.net
Click on the image name you want to see advance to the final:

1️⃣ Dust devil on Mars seen by the Perseverance rover
2️⃣️ Uranus as seen by JWST

📅 Ends: December 21, 2025, 3:00 PM UTC

📊 Show results
December 18, 2025 at 4:14 PM
spacemarschall.net
1st semi-final of ✨ #planetaryScience image of 2025✨
This round features Mars vs. Uranus 🧪⚛️

🗳️ Voting ends on Sunday, Dec. 21, at 3 p.m. UTC/4 p.m. CET/10 a.m. EST/7 a.m. PST/midnight JST.

Here are the two semi-finalists 🔽
Bracket for "BSky Planetary Science Image of 2025" contest, featuring small icons of 16 images grouped into four quarter-finals. There are finalist placeholders against a lunar surface backdrop.
December 18, 2025 at 4:13 PM
spacemarschall.net
There is still time to vote for one of these four great images in the 4th quarter-final of #planetSci image of the year. Currently, it’s a tight race between asteroid Donaldjohanson and comet Lemmon.

The vote can be found in this thread: bsky.app/profile/spac...

#scicomm
The asteroid Donaldjohanson as seen by the Lucy Long-Range Reconnaissance Imager (L’LORRI). This is one of the most detailed images returned by NASA’s Lucy spacecraft during its flyby. This image was taken at 1:51 p.m. EDT (17:51 UTC), April 20, 2025, near closest approach, from a range of approximately 660 miles (1,100 km). The spacecraft’s closest approach distance was 600 miles (960 km), but the image shown was taken approximately 40 seconds beforehand. The image has been sharpened and processed to enhance contrast. Source: https://lucy.swri.edu/DonaldjohansonImageGallery.html Credit: NASA/Goddard/SwRI/Johns Hopkins APL/NOIRLab How many bright tails does Comet Lemmon have? Two. In the featured image it appears to have three, but why? The reason is that the zigzagging brown filament is a persistent meteor train that by luck appeared in front of the distant comet C/2025 A6 (Lemmon). A meteor train is the hot gas and fine dust that remains in the Earth's atmosphere and disperses in the seconds after a bright meteor flashes by. The two bright tails are the blue ion tail stretching across the image, and the white dust tail nearer the green coma on the upper left. All real comet tails originate from the nucleus of the comet inside the coma. The image was captured from Manciano, Italy. Source: https://apod.nasa.gov/apod/ap251027.html Unusual “witch hat” or “helmet-shaped” rock composed entirely of smaller spherules. The image was taken by the NASA rover Perseverance on Mars. Source: https://science.nasa.gov/blog/shocking-spherules/ https://jackiebranc.site/nasas-perseverance-rover-journey/ The Bennu samples revealed magnetite (iron oxide) crystals less than 1 micrometer in size. The individual crystals included hexahedra (six-sided cubes) and octahedra (eight-sided polyhedra). Rob Wardell/Tim Gooding/Tim McCoy/Smithsonian Source: https://edition.cnn.com/2025/01/29/science/asteroid-bennu-building-blocks-of-life
December 17, 2025 at 6:58 PM
spacemarschall.net
Hi friends, please help me spread the word on the open professor position in #planetaryScience we have in Bern 🔽
Dr. Raphael Marschall (@spacemarschall.net)
Hi #planetaryScience folks, we have an open position for a *Professor in Planetary Sciences* at the Space Research & Planetary Sciences Division of the @unibe.ch. Application deadline: *Jan 31, 2026*…
bsky.app
December 17, 2025 at 5:31 PM
spacemarschall.net
What are asteroids made of? Among others, these tiny iron oxide crystals. These come from samples returned from Bennu by NASA's OSIRIS-Rex mission.

This image is also up for the planetary science image of 2025: bsky.app/profile/spac...

Credit: R. Wardell/T. Gooding/T. McCoy/Smithsonian
#SciComm 🧪
The Bennu samples revealed magnetite (iron oxide) crystals less than 1 micrometer in size. The individual crystals included hexahedra (six-sided cubes) and octahedra (eight-sided polyhedra). Rob Wardell/Tim Gooding/Tim McCoy/Smithsonian Source: https://edition.cnn.com/2025/01/29/science/asteroid-bennu-building-blocks-of-life
December 16, 2025 at 7:32 PM
spacemarschall.net
Unusual “helmet-shaped” rock composed entirely of smaller spherules. This image was taken by NASA's Perseverance rover on Mars.

This image is also up for the planetary science image of 2025: bsky.app/profile/spac...

NASA/JPL-Caltech/ASU/ @jackiebranc.site
#SciComm 🧪
Unusual “witch hat” or “helmet-shaped” rock composed entirely of smaller spherules. The image was taken by the NASA rover Perseverance on Mars. Source: https://science.nasa.gov/blog/shocking-spherules/ https://jackiebranc.site/nasas-perseverance-rover-journey/
December 16, 2025 at 6:17 PM
spacemarschall.net
Here, comet C/2025 A6 (Lemmon) crosses behind a meteor train, which is hot gas and fine dust that briefly remains in the Earth's atmosphere after a bright meteor flashes by.

This image is also up for the planetary science image of 2025: bsky.app/profile/spac...

Credit: Massimo Penna
#SciComm 🧪
How many bright tails does Comet Lemmon have? Two. In the featured image it appears to have three, but why? The reason is that the zigzagging brown filament is a persistent meteor train that by luck appeared in front of the distant comet C/2025 A6 (Lemmon). A meteor train is the hot gas and fine dust that remains in the Earth's atmosphere and disperses in the seconds after a bright meteor flashes by. The two bright tails are the blue ion tail stretching across the image, and the white dust tail nearer the green coma on the upper left. All real comet tails originate from the nucleus of the comet inside the coma. The image was captured from Manciano, Italy. Source: https://apod.nasa.gov/apod/ap251027.html
December 16, 2025 at 5:26 PM
spacemarschall.net
NASA's Lucy mission reached another milestone this year with the encounter with asteroid (52246) Donaldjohanson.

This image is also up for the planetary science image of 2025: bsky.app/profile/spac...

Credit: NASA/Goddard/ @swri.org / @jhuapl.bsky.social / @noirlabastro.bsky.social
#SciComm 🧪
The asteroid Donaldjohanson as seen by the Lucy Long-Range Reconnaissance Imager (L’LORRI). This is one of the most detailed images returned by NASA’s Lucy spacecraft during its flyby. This image was taken at 1:51 p.m. EDT (17:51 UTC), April 20, 2025, near closest approach, from a range of approximately 660 miles (1,100 km). The spacecraft’s closest approach distance was 600 miles (960 km), but the image shown was taken approximately 40 seconds beforehand. The image has been sharpened and processed to enhance contrast. Source: https://lucy.swri.edu/DonaldjohansonImageGallery.html Credit: NASA/Goddard/SwRI/Johns Hopkins APL/NOIRLab
December 16, 2025 at 4:51 PM
spacemarschall.net
All you ever wanted to know about what meteorite tell us about Solar System Formation! Check out the newest @issibern.ch book ⬇️

#planetSci
issibern.ch International Space Science Institute (ISSI) @issibern.ch · 10d
Check out the latest Topical Collection in Space Science Reviews on "Evolution of the Solar System: Constraints from Meteorites"
edited by Dominik C. Hezel, Herbert Palme, Jutta Zipfel, Alessandro Morbidelli and Klaus Mezger

Find all papers here (open-access): link.springer.com/collections/...
December 16, 2025 at 3:27 PM
spacemarschall.net
4th quarter-final of ✨ #planetaryScience image of 2025 ✨
This round features mostly small bodies 🧪⚛️

🗳️ Voting ends on Thursday, Dec. 18, at 3 p.m. UTC/4 p.m. CET/10 a.m. EST/7 a.m. PST/midnight JST.
🔽 The voting can be found after the fourth image.

Here come the next four quarter finalists ☄️
Bracket for "BSky Planetary Science Image of 2025" contest, featuring small icons of 16 images grouped into four quarter-finals. There are semi-finalists and finalist placeholders against a lunar surface backdrop.
December 15, 2025 at 5:46 PM
spacemarschall.net
Click on the image name you want to see advance to the semi-final:

1️⃣ Asteroid Donaldjohanson seen by Lucy
2️⃣️ Comet Lemmon and a meteor train
3️⃣ Spherules on Mars seen by Perseverance
4️⃣ Spherules returned from asteroid Bennu

📅 Ends: December 18, 2025, 3:00 PM UTC

📊 Show results
December 15, 2025 at 5:45 PM