Leigh Fletcher
@leighfletcher.bsky.social
Planetary scientist, Dad-in-training, space enthusiast, Professor based at the University of Leicester
https://linktr.ee/leigh.fletcher
https://orcid.org/0000-0001-5834-9588
https://linktr.ee/leigh.fletcher
https://orcid.org/0000-0001-5834-9588
Pinned
Leigh Fletcher
@leighfletcher.bsky.social
· Nov 16
#Uranus reaches 2024 opposition tomorrow. For more than 30 years, #Hubble has watched the shifting Uranian seasons, from southern summer solstice (seen by Voyager 2 in 1986), through equinox in 2007, and (hopefully) on to northern summer solstice in 2030. #planetaryscience 📸 NASA/ESA/STScI/Fletcher
Reposted by Leigh Fletcher
🎵 One of these moons is not like the others, one of these moons just doesn’t belong… 🎵 (it’s Mab, so weird, we love her) 🧪🔭🪐
My latest for @eos.org ahead of #AGU25:
eos.org/articles/ura...
My latest for @eos.org ahead of #AGU25:
eos.org/articles/ura...
Uranus’s Small Moons Are Dark, Red, and Water-Poor - Eos
…Except for Mab, which is even weirder than expected.
eos.org
November 25, 2025 at 3:03 PM
🎵 One of these moons is not like the others, one of these moons just doesn’t belong… 🎵 (it’s Mab, so weird, we love her) 🧪🔭🪐
My latest for @eos.org ahead of #AGU25:
eos.org/articles/ura...
My latest for @eos.org ahead of #AGU25:
eos.org/articles/ura...
Couldn't make out #Saturn's rings at all just now through my telescope (admittedly from a light-polluted vantage point). We are now at the secondary "almost ring-plane crossing" due to Earth's orbit, and we'll have #JWST taking some infrared spectra of Saturn's southern spring next week.. exciting!
#Saturn's simulated appearance from Earth from Jan'25 to Dec'26, showing the changing perspective of the rings as the gas giant moves into southern spring. SkySafari doesn't render the ring shadows, & Saturn is out of view on the other side of the Sun for the ring-plane crossing tomorrow, Mar 23rd.
November 23, 2025 at 5:44 PM
Reposted by Leigh Fletcher
It's Friday, and apparently bluesky is ready for this fun revelation:
Dinosaurs lived on the other side the Galaxy.
Dinosaurs lived on the other side the Galaxy.
November 21, 2025 at 5:11 PM
It's Friday, and apparently bluesky is ready for this fun revelation:
Dinosaurs lived on the other side the Galaxy.
Dinosaurs lived on the other side the Galaxy.
With #Uranus and #Neptune being among the best Solar System targets for JWST, I'm hoping to offer a #PhD studentship for Sep'2026 analysing NIRSpec and MIRI observations of both Ice Giant atmospheres. Contact me for details, deadline Jan 18th! #planetsci
🔭🧪🎢 PhD Project focus: Exploring the Atmospheres of Uranus & Neptune with JWST
We're advertising this project with Prof Leigh Fletcher, using infrared spectral data to investigate the changing atmospheres of the ice giants
For details of all our PhD projects look here: le.ac.uk/study/resear... 🔭🧪🎢
We're advertising this project with Prof Leigh Fletcher, using infrared spectral data to investigate the changing atmospheres of the ice giants
For details of all our PhD projects look here: le.ac.uk/study/resear... 🔭🧪🎢
November 19, 2025 at 6:24 PM
With #Uranus and #Neptune being among the best Solar System targets for JWST, I'm hoping to offer a #PhD studentship for Sep'2026 analysing NIRSpec and MIRI observations of both Ice Giant atmospheres. Contact me for details, deadline Jan 18th! #planetsci
Reposted by Leigh Fletcher
My most important service to solar system planetary science was being a part of the Science Definition Team (SDT), nearly a decade ago, that made the science case for an NASA Ice Giants Orbiter and Entry Probe. Check out our 2017 document: arxiv.org/abs/2511.13946
Ice Giants Pre-Decadal Survey Mission Study Report
The Ice Giants Study was commissioned by NASA to take a fresh look (as of 2017) at science priorities and concepts for missions to the Uranus and Neptune systems in preparation for the third Planetary...
arxiv.org
November 19, 2025 at 4:33 AM
My most important service to solar system planetary science was being a part of the Science Definition Team (SDT), nearly a decade ago, that made the science case for an NASA Ice Giants Orbiter and Entry Probe. Check out our 2017 document: arxiv.org/abs/2511.13946
Our #ESAJuice meeting is over, so a quick moment for some sightseeing. This is the Gänseliesel "goose girl" statue in Göttingen... apparently it's tradition for newly minted PhDs to climb the fountain, kiss the statue, and present a bunch of flowers...
November 14, 2025 at 6:54 PM
Our #ESAJuice meeting is over, so a quick moment for some sightseeing. This is the Gänseliesel "goose girl" statue in Göttingen... apparently it's tradition for newly minted PhDs to climb the fountain, kiss the statue, and present a bunch of flowers...
Although it's not an easy journey (involving planes, trains, & automobiles), I finally made it to @mpsgoettingen.bsky.social for the #ESAJuice Science Team Meeting (our 26th!). Personal first for me: I've never been to Max Planck Institute for Solar System Research and this bit of Germany before.
November 12, 2025 at 9:05 AM
Although it's not an easy journey (involving planes, trains, & automobiles), I finally made it to @mpsgoettingen.bsky.social for the #ESAJuice Science Team Meeting (our 26th!). Personal first for me: I've never been to Max Planck Institute for Solar System Research and this bit of Germany before.
Reposted by Leigh Fletcher
UK science and technology is suffering from a lack of investment, a hostile immigration system, and fragile university finances, reports @cathleenogrady.bsky.social 🧪 #scipolicy
www.science.org/content/arti...
www.science.org/content/arti...
U.K. science sector is ‘bleeding to death,’ lawmakers say in report
House of Lords committee urges government to stem exodus of science and technology companies
www.science.org
November 10, 2025 at 10:08 PM
UK science and technology is suffering from a lack of investment, a hostile immigration system, and fragile university finances, reports @cathleenogrady.bsky.social 🧪 #scipolicy
www.science.org/content/arti...
www.science.org/content/arti...
Looking to start a PhD in Physics & Astronomy in 2026? The team @physicsuol.bsky.social have announced their STFC-funded projects on offer next year, spanning astrophysics, planetary science, and space instrumentation. Deadline: Jan 18th, contact us to learn more!
le.ac.uk/study/resear...
le.ac.uk/study/resear...
November 7, 2025 at 1:32 PM
Looking to start a PhD in Physics & Astronomy in 2026? The team @physicsuol.bsky.social have announced their STFC-funded projects on offer next year, spanning astrophysics, planetary science, and space instrumentation. Deadline: Jan 18th, contact us to learn more!
le.ac.uk/study/resear...
le.ac.uk/study/resear...
Reposted by Leigh Fletcher
In 2023, #NASAWebb observed a spectacular light show on Jupiter, the largest planet in our solar system. The planet’s auroras are hundreds of times brighter and more energetic than Earth’s. Credit: NASA, ESA, CSA, J. Nichols (University of Leicester), M. Zamani (ESA/Webb). 🔭 🧪
November 4, 2025 at 3:23 PM
In 2023, #NASAWebb observed a spectacular light show on Jupiter, the largest planet in our solar system. The planet’s auroras are hundreds of times brighter and more energetic than Earth’s. Credit: NASA, ESA, CSA, J. Nichols (University of Leicester), M. Zamani (ESA/Webb). 🔭 🧪
End of an amazing week @stsci.edu, enormous thanks to @chrisinbaltimore.bsky.social & the ESA team for making me feel so welcome, and to all the researchers from STScI, Johns Hopkins, and APL that came to chat. I'm going home brimming with ideas, and in awe of the work everyone's doing with #JWST.
October 31, 2025 at 7:39 PM
End of an amazing week @stsci.edu, enormous thanks to @chrisinbaltimore.bsky.social & the ESA team for making me feel so welcome, and to all the researchers from STScI, Johns Hopkins, and APL that came to chat. I'm going home brimming with ideas, and in awe of the work everyone's doing with #JWST.
Fourth day of meetings and talks here in Baltimore, and I'd like to say a massive thank-you to those who decided that I was only allowed to meet people called Sarah on Thursday afternoon. Some top-quality trolling there, almost spat out my coffee. #SarahThursday
October 30, 2025 at 1:30 PM
Fourth day of meetings and talks here in Baltimore, and I'd like to say a massive thank-you to those who decided that I was only allowed to meet people called Sarah on Thursday afternoon. Some top-quality trolling there, almost spat out my coffee. #SarahThursday
Thanks to the team at Johns Hopkins Applied Physics Laboratory for hosting me today: home of Dragonfly quadcopter to Titan (model below), Parker Solar Probe, New Horizons to Pluto, DART asteroid impactor, and more. Talked HabWorlds, JWST, heliophysics and exoplanets, all in one exhausting day.
October 28, 2025 at 11:18 PM
Thanks to the team at Johns Hopkins Applied Physics Laboratory for hosting me today: home of Dragonfly quadcopter to Titan (model below), Parker Solar Probe, New Horizons to Pluto, DART asteroid impactor, and more. Talked HabWorlds, JWST, heliophysics and exoplanets, all in one exhausting day.
Over in the *alternate timeline*, I'm at Goddard Spaceflight Centre today chatting to colleagues about JWST and future missions to explore the furthest reaches of our Solar System. But unfortunately we appear to be stuck in *this timeline,* with my NASA colleagues furloughed due to the shutdown.
October 27, 2025 at 12:34 PM
Over in the *alternate timeline*, I'm at Goddard Spaceflight Centre today chatting to colleagues about JWST and future missions to explore the furthest reaches of our Solar System. But unfortunately we appear to be stuck in *this timeline,* with my NASA colleagues furloughed due to the shutdown.
I'm in Baltimore this week, meeting colleagues at Space Telescope and staying near Johns Hopkins' Homewood campus: a beautiful, peaceful campus in the autumn sun, all red brick and marble styled after the Homewood house (1800s, now a museum).
October 26, 2025 at 1:36 PM
I'm in Baltimore this week, meeting colleagues at Space Telescope and staying near Johns Hopkins' Homewood campus: a beautiful, peaceful campus in the autumn sun, all red brick and marble styled after the Homewood house (1800s, now a museum).
Reposted by Leigh Fletcher
ESA’s Jupiter Icy Moons Explorer (Juice) spacecraft is ready to aim its instruments at interstellar comet 3I/ATLAS! 🪐☄️
Here’s what’s happening and why it’s such a rare opportunity 🧵
Here’s what’s happening and why it’s such a rare opportunity 🧵
October 24, 2025 at 2:22 PM
ESA’s Jupiter Icy Moons Explorer (Juice) spacecraft is ready to aim its instruments at interstellar comet 3I/ATLAS! 🪐☄️
Here’s what’s happening and why it’s such a rare opportunity 🧵
Here’s what’s happening and why it’s such a rare opportunity 🧵
Reposted by Leigh Fletcher
Maybe “it’s easier to make an ocean world than we thought.”
Research by Caleb Strom @uofnorthdakota.bsky.social, comments by Richard Cartwright and Chloe Beddingfield @jhuapl.bsky.social. Story by @astrokimcartier.bsky.social. eos.org/articles/tin...
Research by Caleb Strom @uofnorthdakota.bsky.social, comments by Richard Cartwright and Chloe Beddingfield @jhuapl.bsky.social. Story by @astrokimcartier.bsky.social. eos.org/articles/tin...
Tiny Uranian Moon Likely Had a Massive Subsurface Ocean - Eos
Ariel’s tempestuous subsurface ocean may have once composed more than half its total volume.
eos.org
October 24, 2025 at 3:24 PM
Maybe “it’s easier to make an ocean world than we thought.”
Research by Caleb Strom @uofnorthdakota.bsky.social, comments by Richard Cartwright and Chloe Beddingfield @jhuapl.bsky.social. Story by @astrokimcartier.bsky.social. eos.org/articles/tin...
Research by Caleb Strom @uofnorthdakota.bsky.social, comments by Richard Cartwright and Chloe Beddingfield @jhuapl.bsky.social. Story by @astrokimcartier.bsky.social. eos.org/articles/tin...
Reposted by Leigh Fletcher
Before #NASAWebb, it had been 30+ years since astronomers looked closely at Neptune. With Webb, scientists imaged the planet’s auroras and studied its atmosphere, including unexpectedly finding a significant drop in temperature—all at a distance.
Credit: NASA, ESA, CSA, STScI. 🔭 🧪
Credit: NASA, ESA, CSA, STScI. 🔭 🧪
October 23, 2025 at 2:33 PM
Before #NASAWebb, it had been 30+ years since astronomers looked closely at Neptune. With Webb, scientists imaged the planet’s auroras and studied its atmosphere, including unexpectedly finding a significant drop in temperature—all at a distance.
Credit: NASA, ESA, CSA, STScI. 🔭 🧪
Credit: NASA, ESA, CSA, STScI. 🔭 🧪
A day off to decompress, despite the stormy skies. #Leicester's Bradgate Park is fabulous in the autumn colours, fallow deer everywhere. This 850-acre park, a rocky moorland covered in bracken and woodland with the River Lin running through it, is just north of the city and spectacular year round.
October 23, 2025 at 3:57 PM
A day off to decompress, despite the stormy skies. #Leicester's Bradgate Park is fabulous in the autumn colours, fallow deer everywhere. This 850-acre park, a rocky moorland covered in bracken and woodland with the River Lin running through it, is just north of the city and spectacular year round.
Reposted by Leigh Fletcher
wanna feel old?
the date Marty traveled to in the future was ten years ago today
the date Marty traveled to in the future was ten years ago today
October 21, 2025 at 2:06 PM
wanna feel old?
the date Marty traveled to in the future was ten years ago today
the date Marty traveled to in the future was ten years ago today
Reposted by Leigh Fletcher
🔊Announcing a new Physics/Astro PhD scholarship scheme in Edinburgh, for students from a Black heritage, inc mixed Black background. Please help me spread the word. The scholarship covers all tuition fees, living costs & research travel. #blackinSTEM 🔭👩🔬⚛️
ℹ️: www.ph.ed.ac.uk/studying/pos...
ℹ️: www.ph.ed.ac.uk/studying/pos...
October 20, 2025 at 3:52 PM
🔊Announcing a new Physics/Astro PhD scholarship scheme in Edinburgh, for students from a Black heritage, inc mixed Black background. Please help me spread the word. The scholarship covers all tuition fees, living costs & research travel. #blackinSTEM 🔭👩🔬⚛️
ℹ️: www.ph.ed.ac.uk/studying/pos...
ℹ️: www.ph.ed.ac.uk/studying/pos...
Friday night after a long week. Time for a laugh with @mattgreencomedy.com at @theytheatre.bsky.social in #Leicester
October 17, 2025 at 6:56 PM
Friday night after a long week. Time for a laugh with @mattgreencomedy.com at @theytheatre.bsky.social in #Leicester
Folks were tracking #JWST proposals to see if Cycle 5 would break records (again). With success rates<10%, that means ~2500 of these amazing ideas will not get time, so will be coming right back at Cycle 6. So.... why not extend Cycle 5 and offer twice as many hours to halve the stress...?
October 16, 2025 at 12:47 PM
Folks were tracking #JWST proposals to see if Cycle 5 would break records (again). With success rates<10%, that means ~2500 of these amazing ideas will not get time, so will be coming right back at Cycle 6. So.... why not extend Cycle 5 and offer twice as many hours to halve the stress...?
Reposted by Leigh Fletcher
Excellent piece from the Planetary Society highlighting some of the human stories of NASA's workforce losses: www.planetary.org/articles/400...
4,000 gone: Inside NASA’s brain drain
In exclusive interviews, ex-NASA scientists speak out on the impact of the agency's mass departures.
www.planetary.org
October 15, 2025 at 4:42 PM
Excellent piece from the Planetary Society highlighting some of the human stories of NASA's workforce losses: www.planetary.org/articles/400...
Between the lowest and highest proposal numbers I've seen, there are already 1600 new #JWSTCycle5 proposals, ~14hrs before the deadline (8:00 pm US Eastern Daylight Time)...
The JWST Cycle 5 "Procrastination Monitor", i.e. Molly's proposal counter submission form, is up an running. Please fill it out if you have data to add to it. And do share! #JWSTCycle5
docs.google.com/forms/d/e/1F...
docs.google.com/forms/d/e/1F...
JWST Cycle 5 Proposal Procrastination Monitor
An anonymous way to monitor JWST proposal submission times
In the email from proposal-submission@stsci, the subject line will be like, "JWST Phase I Proposal 3434 submission 4 received". Here, 3434 =...
docs.google.com
October 15, 2025 at 9:58 AM
Between the lowest and highest proposal numbers I've seen, there are already 1600 new #JWSTCycle5 proposals, ~14hrs before the deadline (8:00 pm US Eastern Daylight Time)...