Linn Boldt-Christmas
@nplinnspace.bsky.social
🇸🇪 Exoplanet atmospheres + chemistry + formation at Uppsala University 🪐🔭 Also into astrobiology, policy, climate, equality/EDI, and scicomm ✨ (she/her) – linnboldtchristmas.wordpress.com
Pinned
VLT/CRIRES+ observations of warm Neptune WASP-107 b: Molecular detections and challenges in ground-based transmission spectroscopy of cooler and cloudy exoplanets
Atmospheres of transiting exoplanets can be studied spectroscopically using space-based or ground-based observations. Each has its own strengths and weaknesses, so there are benefits to both approache...
arxiv.org
Do you love WASP-107 b? Do you love making use of *both* ground VLT + space JWST obs to detect molecules in a "warm" (Teq<800K) #exoplanet in transmission, even in a crazy confusing cloudy atmosphere?!
🚨 It's PAPER* DAY! Which means #scicomm thread!
🧵⬇️🔭🪐🧪
*pre-print!
arxiv.org/abs/2508.18964
🚨 It's PAPER* DAY! Which means #scicomm thread!
🧵⬇️🔭🪐🧪
*pre-print!
arxiv.org/abs/2508.18964
Reposted by Linn Boldt-Christmas
Amazing thread: every time we expand the range of what's possible for terrestrial extremophiles, the likelihood life exists elsewhere in the galaxy goes up for me.
So happy to announce our new preprint, “A geothermal amoeba sets a new upper temperature limit for eukaryotes.” We cultured a novel amoeba from Lassen Volcanic NP (CA, USA) that divides at 63°C (145°F) 🔥 - a new record for euk growth!
#protistsonsky 🧵
#protistsonsky 🧵
November 25, 2025 at 10:34 PM
Amazing thread: every time we expand the range of what's possible for terrestrial extremophiles, the likelihood life exists elsewhere in the galaxy goes up for me.
Reposted by Linn Boldt-Christmas
🔭🧪🎢 PhD Project focus: Novel Pu Gd oxides for Space Nuclear Power Systems
We're advertising this project with Dr Emily Jane Watkinson, investigating new options to power exploration of the outer solar system
For details of all our PhD projects look here: le.ac.uk/study/resear... 🔭🧪🎢
We're advertising this project with Dr Emily Jane Watkinson, investigating new options to power exploration of the outer solar system
For details of all our PhD projects look here: le.ac.uk/study/resear... 🔭🧪🎢
STFC | Postgraduate research | University of Leicester
STFC Studentships in Physics and Astronomy. University of Leicester
le.ac.uk
November 25, 2025 at 12:19 PM
🔭🧪🎢 PhD Project focus: Novel Pu Gd oxides for Space Nuclear Power Systems
We're advertising this project with Dr Emily Jane Watkinson, investigating new options to power exploration of the outer solar system
For details of all our PhD projects look here: le.ac.uk/study/resear... 🔭🧪🎢
We're advertising this project with Dr Emily Jane Watkinson, investigating new options to power exploration of the outer solar system
For details of all our PhD projects look here: le.ac.uk/study/resear... 🔭🧪🎢
Reposted by Linn Boldt-Christmas
That is an ex-comet
Fantastic work by Ariel Graykowski and our @setiinstitute.bsky.social citizen scientists.
Comet C/2025 K1 (ATLAS) is breaking apart — and some of you caught it live. After passing 0.3 AU from the Sun, it erupted, and three days later a third appeared.
K1 is now officially in pieces.
Comet C/2025 K1 (ATLAS) is breaking apart — and some of you caught it live. After passing 0.3 AU from the Sun, it erupted, and three days later a third appeared.
K1 is now officially in pieces.
November 25, 2025 at 6:09 AM
That is an ex-comet
Reposted by Linn Boldt-Christmas
If your planet's not too big, and your transit spectrum is flatter than you'd think, your aerosols might be clumpy.
Owen+ arxiv.org/abs/2511.19013
🧪🔭🪐 #exoplanets
Owen+ arxiv.org/abs/2511.19013
🧪🔭🪐 #exoplanets
Resolving the flat-spectrum conundrum: clumpy aerosol distributions in sub-Neptune atmospheres
Transmission spectroscopy of sub-Neptunes was expected to reveal their compositions and hence origins, yet many show flat near- to mid-infrared spectra. Such spectra can be explained either by metal d...
arxiv.org
November 25, 2025 at 8:32 AM
If your planet's not too big, and your transit spectrum is flatter than you'd think, your aerosols might be clumpy.
Owen+ arxiv.org/abs/2511.19013
🧪🔭🪐 #exoplanets
Owen+ arxiv.org/abs/2511.19013
🧪🔭🪐 #exoplanets
Reposted by Linn Boldt-Christmas
Norway’s icy landscapes are a dream for both Northern lights lovers and space fanatics.
🇳🇴
In 1987 Norway became a full member of @esa.int and these are the country's contributions to Europe's heavy-lift rocket #Ariane6
🚀
www.esa.int/Enabling_Sup...
🇳🇴
In 1987 Norway became a full member of @esa.int and these are the country's contributions to Europe's heavy-lift rocket #Ariane6
🚀
www.esa.int/Enabling_Sup...
November 24, 2025 at 4:11 PM
Norway’s icy landscapes are a dream for both Northern lights lovers and space fanatics.
🇳🇴
In 1987 Norway became a full member of @esa.int and these are the country's contributions to Europe's heavy-lift rocket #Ariane6
🚀
www.esa.int/Enabling_Sup...
🇳🇴
In 1987 Norway became a full member of @esa.int and these are the country's contributions to Europe's heavy-lift rocket #Ariane6
🚀
www.esa.int/Enabling_Sup...
Reposted by Linn Boldt-Christmas
We are hiring a new Assistant Professor in Astrophysics at Trinity College Dublin!! ☘
Job ad here: aas.org/jobregister/...
Deadline: Jan 02 2026
Please share widely! 🪐🔭
Job ad here: aas.org/jobregister/...
Deadline: Jan 02 2026
Please share widely! 🪐🔭
Assistant Professor in Astrophysics | American Astronomical Society
The School of Physics at Trinity College Dublin invites applications for a position at the level of Assistant Professor in the field of observational or theoretical astrophysics. We seek motivated ind...
aas.org
November 24, 2025 at 12:27 PM
We are hiring a new Assistant Professor in Astrophysics at Trinity College Dublin!! ☘
Job ad here: aas.org/jobregister/...
Deadline: Jan 02 2026
Please share widely! 🪐🔭
Job ad here: aas.org/jobregister/...
Deadline: Jan 02 2026
Please share widely! 🪐🔭
🔭🧪 A+ thread below summarising what kind of incoming asteroids/objects we can, cannot, and *kind of* can track ahead of impact and thus protect ourselves from ⬇️
Then decide for yourself if you find it reassuring or not…
Then decide for yourself if you find it reassuring or not…
OK, so. Below a certain size, the atmosphere takes care of the problem--objects below 10 meters in size, say, are going to give a great showy fireball but not do any damage on the ground unless you're really personally unlucky, like the teenager who owned this car.
meteoritecar.com
meteoritecar.com
The Peekskill Meteorite Car Official Website
The official website of the Peekskill Meteorite Car, the most famous object to ever be struck by a meteorite.
meteoritecar.com
November 22, 2025 at 1:32 PM
🔭🧪 A+ thread below summarising what kind of incoming asteroids/objects we can, cannot, and *kind of* can track ahead of impact and thus protect ourselves from ⬇️
Then decide for yourself if you find it reassuring or not…
Then decide for yourself if you find it reassuring or not…
Reposted by Linn Boldt-Christmas
Why are planetary scientists, astrobiologists and and SETI scientists so negative (pissed off, even) about Avi Loeb’s repeated claims that 3I/Atlas may be an invading alien spaceship?
🧵
🧪🔭🛸
(1/7)
🧵
🧪🔭🛸
(1/7)
November 10, 2025 at 11:41 PM
Why are planetary scientists, astrobiologists and and SETI scientists so negative (pissed off, even) about Avi Loeb’s repeated claims that 3I/Atlas may be an invading alien spaceship?
🧵
🧪🔭🛸
(1/7)
🧵
🧪🔭🛸
(1/7)
Reposted by Linn Boldt-Christmas
It’s widely known (and, I think, pretty uncontroversial) that learning requires effort — specifically, if you don’t have to work at getting the knowledge, it won’t stick.
Even if an LLM could be trusted to give you correct information 100% of the time, it would be an inferior method of learning it.
Even if an LLM could be trusted to give you correct information 100% of the time, it would be an inferior method of learning it.
Relying on ChatGPT to teach you about a topic leaves you with shallower knowledge than Googling and reading about it, according to new research that compared what more than 10,000 people knew after using one method or the other.
Shared by @gizmodo.com: buff.ly/yAAHtHq
Shared by @gizmodo.com: buff.ly/yAAHtHq
November 21, 2025 at 12:49 PM
It’s widely known (and, I think, pretty uncontroversial) that learning requires effort — specifically, if you don’t have to work at getting the knowledge, it won’t stick.
Even if an LLM could be trusted to give you correct information 100% of the time, it would be an inferior method of learning it.
Even if an LLM could be trusted to give you correct information 100% of the time, it would be an inferior method of learning it.
Reposted by Linn Boldt-Christmas
There are about 400 photons and 300 neutrinos in every cubic cm of the Universe left over from the Big Bang 🧪
Man, everything is so bleak, anyone got a fun fact or little bit of trivia they want to share
November 21, 2025 at 12:41 PM
There are about 400 photons and 300 neutrinos in every cubic cm of the Universe left over from the Big Bang 🧪
Reposted by Linn Boldt-Christmas
We have a PhD opportunity at the University of Reading focused on analysing Jupiter and Saturn auroral observations!
Title: Investigating Earth-like responses to the Solar Wind in Gas Giant Upper Atmospheres
Supervisor: me!
Full description/application portal:
www.findaphd.com/phds/project...
Title: Investigating Earth-like responses to the Solar Wind in Gas Giant Upper Atmospheres
Supervisor: me!
Full description/application portal:
www.findaphd.com/phds/project...
Crocus DLA
crocus-dla.ac.uk
November 20, 2025 at 2:11 PM
We have a PhD opportunity at the University of Reading focused on analysing Jupiter and Saturn auroral observations!
Title: Investigating Earth-like responses to the Solar Wind in Gas Giant Upper Atmospheres
Supervisor: me!
Full description/application portal:
www.findaphd.com/phds/project...
Title: Investigating Earth-like responses to the Solar Wind in Gas Giant Upper Atmospheres
Supervisor: me!
Full description/application portal:
www.findaphd.com/phds/project...
🔭🧪 Absolutely blown away by the pedagogy and the *artistry* of this goliath piece of #scicomm ⬇️ Just look at these drawings!!
This must have taken an incredible amount of time & talent, and I learned so much (about a fairly-distant-subfield-to-mine) from it! So grateful for scientists who do this!
This must have taken an incredible amount of time & talent, and I learned so much (about a fairly-distant-subfield-to-mine) from it! So grateful for scientists who do this!
November 20, 2025 at 7:31 AM
🔭🧪 Absolutely blown away by the pedagogy and the *artistry* of this goliath piece of #scicomm ⬇️ Just look at these drawings!!
This must have taken an incredible amount of time & talent, and I learned so much (about a fairly-distant-subfield-to-mine) from it! So grateful for scientists who do this!
This must have taken an incredible amount of time & talent, and I learned so much (about a fairly-distant-subfield-to-mine) from it! So grateful for scientists who do this!
Reposted by Linn Boldt-Christmas
To finish it off, I've also done an annotated version of the paper complete with silly drawings and accessible language! These are inspired by @clairelamman.bsky.social , and you can read this and more here: ryanwhite1.github.io/wolf-rayet.h...
4/4 ⚛️🔭🧪
4/4 ⚛️🔭🧪
November 19, 2025 at 10:18 PM
To finish it off, I've also done an annotated version of the paper complete with silly drawings and accessible language! These are inspired by @clairelamman.bsky.social , and you can read this and more here: ryanwhite1.github.io/wolf-rayet.h...
4/4 ⚛️🔭🧪
4/4 ⚛️🔭🧪
Reposted by Linn Boldt-Christmas
First time in a while where I’ve had the “wait that’s an IMAGE. That’s the DATA.” double take.
Very excited to share the NASA/ESA/STScI press release of our team's work on Apep! It's a terrific writeup, complete with a brand new beautiful visualisation of the nebula geometry.
1/? ⚛️🔭🧪
science.nasa.gov/missions/web...
1/? ⚛️🔭🧪
science.nasa.gov/missions/web...
Webb First to Show 4 Dust Shells 'Spiraling' Apep, Limits Long Orbit - NASA Science
NASA’s James Webb Space Telescope has delivered a first of its kind: a crisp mid-infrared image of a system of four serpentine spirals of dust, one expanding
science.nasa.gov
November 20, 2025 at 12:14 AM
First time in a while where I’ve had the “wait that’s an IMAGE. That’s the DATA.” double take.
Reposted by Linn Boldt-Christmas
Remember that lovely aurora last week?
Well...um...this is what Euclid saw... 😱
🧵
Well...um...this is what Euclid saw... 😱
🧵
November 19, 2025 at 11:51 AM
Remember that lovely aurora last week?
Well...um...this is what Euclid saw... 😱
🧵
Well...um...this is what Euclid saw... 😱
🧵
Reposted by Linn Boldt-Christmas
If you live in France, a new documentary about 'Oumuamua comes out Thursday evening, starting at 9pm on the France 5. Replays on france.tv after
I was scientific advisor (and I show up in several places), which was a great pleasure.
www.francetvpro.fr/contenu-de-p...
I was scientific advisor (and I show up in several places), which was a great pleasure.
www.francetvpro.fr/contenu-de-p...
France TV - Replay et Direct tv des chaînes France Télévisions (ex Pluzz)
Retrouvez toutes les vidéos, articles et podcasts des programmes des chaînes de France Télévisions.
france.tv
November 18, 2025 at 11:21 AM
If you live in France, a new documentary about 'Oumuamua comes out Thursday evening, starting at 9pm on the France 5. Replays on france.tv after
I was scientific advisor (and I show up in several places), which was a great pleasure.
www.francetvpro.fr/contenu-de-p...
I was scientific advisor (and I show up in several places), which was a great pleasure.
www.francetvpro.fr/contenu-de-p...
Reposted by Linn Boldt-Christmas
collaborative proposal writing tip:
start the narrative out with one font size larger than the minimum allowed. Then in the final days when everyone is squeezed for space, drop down to the proper font size. This forces everyone to write more concisely from the start.
start the narrative out with one font size larger than the minimum allowed. Then in the final days when everyone is squeezed for space, drop down to the proper font size. This forces everyone to write more concisely from the start.
November 17, 2025 at 6:55 PM
collaborative proposal writing tip:
start the narrative out with one font size larger than the minimum allowed. Then in the final days when everyone is squeezed for space, drop down to the proper font size. This forces everyone to write more concisely from the start.
start the narrative out with one font size larger than the minimum allowed. Then in the final days when everyone is squeezed for space, drop down to the proper font size. This forces everyone to write more concisely from the start.
Reposted by Linn Boldt-Christmas
Everyone: sees my paper on arxiv: arxiv.org/abs/2511.10801
What I see: 6 years of tears, struggles, COVID pandemic, medical and mental health chronic issues, multiple surgeries, adopting my two fur babies, getting married, healing from trauma, and so much more. And still submitting this paper! 🥹😭💖
What I see: 6 years of tears, struggles, COVID pandemic, medical and mental health chronic issues, multiple surgeries, adopting my two fur babies, getting married, healing from trauma, and so much more. And still submitting this paper! 🥹😭💖
November 17, 2025 at 6:03 PM
Everyone: sees my paper on arxiv: arxiv.org/abs/2511.10801
What I see: 6 years of tears, struggles, COVID pandemic, medical and mental health chronic issues, multiple surgeries, adopting my two fur babies, getting married, healing from trauma, and so much more. And still submitting this paper! 🥹😭💖
What I see: 6 years of tears, struggles, COVID pandemic, medical and mental health chronic issues, multiple surgeries, adopting my two fur babies, getting married, healing from trauma, and so much more. And still submitting this paper! 🥹😭💖
🔭 Welcome to the world, brand new Moon crater! Impact caught yesterday morning in the video below ⬇️ Such a cool event to have captured! 🤩
Vous assistez, quasiment en direct à la formation d'un cratère sur la Lune, avec un impact filmé ce matin !
November 17, 2025 at 11:19 AM
🔭 Welcome to the world, brand new Moon crater! Impact caught yesterday morning in the video below ⬇️ Such a cool event to have captured! 🤩
Reposted by Linn Boldt-Christmas
Interested in pursuing a PhD in Astrophysics?
The Centre for Astrophysics Research @herts.ac.uk is advertising many projects, including some I'm supervising on Galaxies, Black Holes and Cosmology!
Deadline: February 2nd 2026
www.herts.ac.uk/research/cen...
#astro #cosmology #PhD #uniofherts
The Centre for Astrophysics Research @herts.ac.uk is advertising many projects, including some I'm supervising on Galaxies, Black Holes and Cosmology!
Deadline: February 2nd 2026
www.herts.ac.uk/research/cen...
#astro #cosmology #PhD #uniofherts
Research degrees and studentships
Postgraduate Research Opportunities
www.herts.ac.uk
November 17, 2025 at 10:11 AM
Interested in pursuing a PhD in Astrophysics?
The Centre for Astrophysics Research @herts.ac.uk is advertising many projects, including some I'm supervising on Galaxies, Black Holes and Cosmology!
Deadline: February 2nd 2026
www.herts.ac.uk/research/cen...
#astro #cosmology #PhD #uniofherts
The Centre for Astrophysics Research @herts.ac.uk is advertising many projects, including some I'm supervising on Galaxies, Black Holes and Cosmology!
Deadline: February 2nd 2026
www.herts.ac.uk/research/cen...
#astro #cosmology #PhD #uniofherts
Reposted by Linn Boldt-Christmas
ESA’s Mars and Jupiter missions observe comet 3I/ATLAS
@esa.int is making the most of its interplanetary missions to observe the comet from multiple vantage points. 🧪🔭
www.esa.int/ESA_Multimed... @science.esa.int #3IATLAS
@esa.int is making the most of its interplanetary missions to observe the comet from multiple vantage points. 🧪🔭
www.esa.int/ESA_Multimed... @science.esa.int #3IATLAS
November 16, 2025 at 10:40 AM
ESA’s Mars and Jupiter missions observe comet 3I/ATLAS
@esa.int is making the most of its interplanetary missions to observe the comet from multiple vantage points. 🧪🔭
www.esa.int/ESA_Multimed... @science.esa.int #3IATLAS
@esa.int is making the most of its interplanetary missions to observe the comet from multiple vantage points. 🧪🔭
www.esa.int/ESA_Multimed... @science.esa.int #3IATLAS
Reposted by Linn Boldt-Christmas
Whoa. The scale of this thing.
That blast wave radiating away from the flare location is impressive. Esp. when you think about the size of the Earth in comparison.
It’s so very near that we live so close to a star and can watch its behaviour and activity.
A star and it’s just right there!
That blast wave radiating away from the flare location is impressive. Esp. when you think about the size of the Earth in comparison.
It’s so very near that we live so close to a star and can watch its behaviour and activity.
A star and it’s just right there!
Here is the X5.1 flare in straight EUV light. We are looking at the 193 Å "gold" filter here. The flare is the bright flash, and immediately, you can see a giant blast wave racing through the Sun's corona, lifting tons of plasma into space as an Earth-directed CME.
November 11, 2025 at 6:52 PM
Whoa. The scale of this thing.
That blast wave radiating away from the flare location is impressive. Esp. when you think about the size of the Earth in comparison.
It’s so very near that we live so close to a star and can watch its behaviour and activity.
A star and it’s just right there!
That blast wave radiating away from the flare location is impressive. Esp. when you think about the size of the Earth in comparison.
It’s so very near that we live so close to a star and can watch its behaviour and activity.
A star and it’s just right there!
Reposted by Linn Boldt-Christmas
It seems like just yesterday that we were in design reviews for GRAVITY the OG version - now there‘s GRAVITY+ with multiple lasers! ESO and Europe/Chile are powerhouses for ground-based astronomy right now. 🔭
1/ Milestone achieved by the VLTI upgrade GRAVITY+: a laser has been installed at each of the previously unequipped VLT Unit Telescopes.
This will dramatically enhance the VLTI observing power.
Discover more with #ChasingStarlight: https://www.youtube.com/watch?v=TzK1B3VU1L8
🔭 🧪
This will dramatically enhance the VLTI observing power.
Discover more with #ChasingStarlight: https://www.youtube.com/watch?v=TzK1B3VU1L8
🔭 🧪
November 10, 2025 at 12:33 PM
It seems like just yesterday that we were in design reviews for GRAVITY the OG version - now there‘s GRAVITY+ with multiple lasers! ESO and Europe/Chile are powerhouses for ground-based astronomy right now. 🔭
Reposted by Linn Boldt-Christmas
Like the sonogram of a planetary system
WOW!
An incredible discovery. The first ever image of a baby exoplanet embedded in the dust rings from which planets are forming around a star. Confirms the developing view of planet formation that we’ve never before seen in action.
🧪🔭
www.universiteitleiden.nl/en/news/2025...
An incredible discovery. The first ever image of a baby exoplanet embedded in the dust rings from which planets are forming around a star. Confirms the developing view of planet formation that we’ve never before seen in action.
🧪🔭
www.universiteitleiden.nl/en/news/2025...
November 8, 2025 at 3:12 PM
Like the sonogram of a planetary system
Reposted by Linn Boldt-Christmas
See below if you're interested in doing a PhD on stars or clusters! Trumpler 14 is an especially awesome cluster in the Carina Nebula, and doing your PhD on it (or star cluster formation more generally) would be tons of fun 😉
The @herts.ac.uk astronomy MSc and PhD applications are open.
I'm offering PhD projects on JWST spectroscopy of young stars in Tr 14 and star-cluster formation.
I'm also offering an MSc project on variability of YSOs.
www.herts.ac.uk/research/cen...
#galactic #stellarastro #astro #Physics
I'm offering PhD projects on JWST spectroscopy of young stars in Tr 14 and star-cluster formation.
I'm also offering an MSc project on variability of YSOs.
www.herts.ac.uk/research/cen...
#galactic #stellarastro #astro #Physics
Solar, Stellar and Time-domain Astrophysics
Star formation and Stellar Evolution PhD Projects.
herts.ac.uk
November 7, 2025 at 8:03 AM
See below if you're interested in doing a PhD on stars or clusters! Trumpler 14 is an especially awesome cluster in the Carina Nebula, and doing your PhD on it (or star cluster formation more generally) would be tons of fun 😉