Dr. Raphael Marschall
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Dr. Raphael Marschall
@spacemarschall.net
4.1K followers 360 following 920 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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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
watershedlab.bsky.social
After reviewing nearly 200 applications from prospective grad students and postdocs over the past few months for a couple different 🧪⚒️ postings, here are some tips, at least as they apply to North American positions. I hope they help future applicants. Share with your networks. 🧵
January 4, 2026 at 2:17 PM
Reposted by Dr. Raphael Marschall
mpoessel.de
Heute habe ich ein Video von einem der für mich beeindruckendsten Physik-Miniversuche gemacht. Dazu habe ich einen Wanderstiefel an seinen beiden Schnürsenkeln aufgehängt. Eine doppelte Drehung des Stiefels lässt sich rückgängig machen, ohne die Orientierung des Stiefels zu verändern! 1/
January 4, 2026 at 2:42 PM
Reposted by Dr. Raphael Marschall
seanmcarroll.bsky.social
The calendar changes— on the one hand, an entirely arbitrary chronological signifier. On the other, an absolutely necessary chance to catch our breath, renew our energies, and look ahead. Let’s go!
January 1, 2026 at 5:44 AM
Reposted by Dr. Raphael Marschall
theymaybeparted.bsky.social
“Produce your own dream. If you want to save Peru, go save Peru. … I can’t wake you up. You can wake you up. I can’t cure you. You can cure you.”

- John Lennon, 1980

(Annual post. My favorite John Lennon quote, btw)

#HappyNewYear2026
January 1, 2026 at 5:19 AM
spacemarschall.net
As we embark on this new year, may it bring you joy, health and fulfillment. I wish everyone all the best for 2026 ✨
In the center of the image a man walking on a stony beach. On the right side waves are crashing onto shore and in the background buildings are lit up orange from a sunset.
December 31, 2025 at 10:07 PM
spacemarschall.net
This image, taken by astronaut Nichole Ayers, is also a finalist in our ✨Planetary Science Image of the Year✨! You can still vote for it in this thread: bsky.app/profile/spac...
exploration.esa.int ESA Exploration @exploration.esa.int · 11d
Can you see fireworks from space? 🎆

You can if you get lucky, but nature always puts on the best show.

We're celebrating the New Year with this stunning sight from the International Space Station: a giant blue jet and red sprites shooting upwards from a thunderstorm.

🔗 www.esa.int/ESA_Multimed...
Fireworks from space
Fireworks from space
www.esa.int
December 30, 2025 at 10:15 AM
spacemarschall.net
Who will win ✨ #planetaryScience image of 2025 ✨?

Currently, Uranus is winning, but you still have time to vote for either finalist in this thread here until tomorrow, Dec. 30, at 3 p.m. UTC/4 p.m. CET/10 a.m. EST/7 a.m. PST/midnight JST: bsky.app/profile/spac...

🧪⚛️
Final machup of planetary science image of the year with "Uranus as seen by JWST" vs "Gigantic TLE above Mexico seen from the ISS". Uranus image description: 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 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 Description Earth: On July 3rd, astronaut Nichole Ayers photographed a gigantic jet from the ISS. These rare upward directed electrical discharges extend ~90-100 km high into the mesosphere. The jet originated from a thunderstorm over Northern Mexico, with city lights from South Texas and the green airglow layer visible along Earth’s limb. I processed this image from the RAW file, adjusting the color profile, white balance and contrast and applied Lightroom's machine learning denoise with low strength. The RAW was provided to me by Frankie Lucena, his analysis of the event, correlating it to measurements from the Geostationary Lightning mapper and ELF-VLF radio signals can be found here: https://spaceweathergallery2.com/indiv_upload.php?upload_id=224355 City annotations referenced from Riccardo Rossi: https://x.com/RikyUnreal/status/1942367538714734609 Original image listing in the NASA archive: https://eol.jsc.nasa.gov/SearchPhotos/photo.pl?mission=ISS073&roll=E&frame=281502 Credit: Nichole Ayers / NASA JSC / ESRS / Simeon Schmauß
December 29, 2025 at 9:22 PM
spacemarschall.net
Last year, this spectacular image of Jupiter's moon Io won the Planetary Science Image of the Year 🧪

Credit: NASA/JPL-Caltech/SwRI/MSSS/Kevin M. Gill,
@kevinmgill.bsky.social

Who will win this year? Vote here: bsky.app/profile/spac...
A true color image of Io as imaged by Juno on December 30, 2023 during its closest flyby. This is the closest a spacecraft got in the past 20 years. North is up and this side of Io faces Jupiter. The ↄ-shaped black spot is Loki Patera, to its north is the black spot Amaterasu Patera volcano and further north is the Dazhbog Patera also a black spot. Source: https://commons.wikimedia.org/wiki/File:Io_imaged_by_Juno_spacecraft.png NASA/JPL-Caltech/SwRI/MSSS/Kevin M. Gill, @kevinmgill.bsky.social
December 29, 2025 at 2:13 PM
spacemarschall.net
The James Webb Space Telescope (JWST) is revolutionising our understanding of the universe. It's also doing it for the Solar System with spectacular data, such as that of Uranus here.

If you like this image, you can vote for it here: bsky.app/profile/spac...

🧪⚛️ #sciComm #planetSci
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 29, 2025 at 2:06 PM
spacemarschall.net
I find this image quite fascinating and beautiful. It's showing lightning discharging towards space. Astronaut Nichole Ayers took this image from the International Space Station on July 3, 2025.

If you like it too, you can vote for it here:
bsky.app/profile/spac...

🧪⚛️ #sciComm #planetSci
Description by Simeon Schmauß (https://www.flickr.com/photos/semeion/54664805569/): On July 3rd, astronaut Nichole Ayers photographed a gigantic jet from the ISS. These rare upward directed electrical discharges extend ~90-100 km high into the mesosphere. The jet originated from a thunderstorm over Northern Mexico, with city lights from South Texas and the green airglow layer visible along Earth’s limb. I processed this image from the RAW file, adjusting the color profile, white balance and contrast and applied Lightroom's machine learning denoise with low strength. The RAW was provided to me by Frankie Lucena, his analysis of the event, correlating it to measurements from the Geostationary Lightning mapper and ELF-VLF radio signals can be found here: https://spaceweathergallery2.com/indiv_upload.php?upload_id=224355 City annotations referenced from Riccardo Rossi: https://x.com/RikyUnreal/status/1942367538714734609 Original image listing in the NASA archive: https://eol.jsc.nasa.gov/SearchPhotos/photo.pl?mission=ISS073&roll=E&frame=281502 Credit: Nichole Ayers / NASA JSC / ESRS / Simeon Schmauß @stim3on.bsky.social
December 29, 2025 at 1:55 PM
Reposted by Dr. Raphael Marschall
andrealuck.bsky.social
Hey Martians, did I mention we now also have a video of epic Phobos passing over a Martian dust storm near Pavonis Mons? 🌪️🌋🥔

Video & full info: flic.kr/p/2rNN8wk
Credit: ESA/DLR/FUBerlin/AndreaLuck CC BY

@esa.int Mars Express HRSC
300 MP Photo quoted below
Easy zoom: easyzoom.com/image/674026
December 27, 2025 at 2:01 PM
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 · 20d
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