Sean McMahon
@seanhmcmahon.bsky.social
Astrobiologist & palaeobiologist @ Univ. Edinburgh / Co-director, UK Centre for Astrobiology / Director, MSc Astrobiology & Planetary Sciences / Deputy Chair, Council for the Defence of British Universities. https://www.astrobiology.ac.uk/mcmahon-group
Pinned
🚨New preprint (not peer reviewed)! Last year, NASA announced "potential biosignatures" on Mars: bleached spots in rust-red rocks. Here, we show that rust-dissolving bacteria really can make spots like these. Next step: see if we can make them without bacteria! #astrobiology doi.org/10.64898/202...
good thread
An astonishing headline reporting on new observations from a team led to Nikku Madhusudhan claims they’ve found ‘hints of life’ on a planet orbiting a dwarf star some 124 light years away. What’s going on? (1/n) www.bbc.co.uk/news/article... 🔭 🧪
Promising hints of life found on distant planet K2-18b
Scientists find new but tentative evidence that a faraway world orbiting another star may be home to life.
www.bbc.co.uk
February 8, 2026 at 11:08 AM
good thread
Reposted by Sean McMahon
The volcano erupted, spraying linoleum and carpeting into the air.
"Oh my god," the geologist gasped. "The lava is floor!"
"Oh my god," the geologist gasped. "The lava is floor!"
January 31, 2026 at 3:54 PM
The volcano erupted, spraying linoleum and carpeting into the air.
"Oh my god," the geologist gasped. "The lava is floor!"
"Oh my god," the geologist gasped. "The lava is floor!"
Reposted by Sean McMahon
Rachel Reeves: "It is not right that people who don't go to university bear the cost for others to." I don't use local leisure centres and I don't drive, so will I be made exempt for taxation that pays for all that stuff? Or is it only education we'll be going after
January 29, 2026 at 6:45 PM
Rachel Reeves: "It is not right that people who don't go to university bear the cost for others to." I don't use local leisure centres and I don't drive, so will I be made exempt for taxation that pays for all that stuff? Or is it only education we'll be going after
An excellent explainer of our new preprint from James Robinson of the multiverses.xyz podcast!
Life on Mars? how a muddy Scottish pond adds to the case #astrobiology #science #mars
YouTube video by multiverses
www.youtube.com
January 25, 2026 at 12:53 PM
An excellent explainer of our new preprint from James Robinson of the multiverses.xyz podcast!
Reposted by Sean McMahon
"It is the moon, I ken her horn,
That's blinkin' in the lift sae hie;
She shines sae bright to wyle us hame,
But, by my sooth, she'll wait a wee!"
Lots of despair & sadness watching the 🇺🇸news today.
I'm hoping Burns can lift your spirit today.
🏴Happy #BurnsNight🏴
📷@tomduffinphotos.bsky.social
That's blinkin' in the lift sae hie;
She shines sae bright to wyle us hame,
But, by my sooth, she'll wait a wee!"
Lots of despair & sadness watching the 🇺🇸news today.
I'm hoping Burns can lift your spirit today.
🏴Happy #BurnsNight🏴
📷@tomduffinphotos.bsky.social
January 25, 2026 at 9:08 AM
"It is the moon, I ken her horn,
That's blinkin' in the lift sae hie;
She shines sae bright to wyle us hame,
But, by my sooth, she'll wait a wee!"
Lots of despair & sadness watching the 🇺🇸news today.
I'm hoping Burns can lift your spirit today.
🏴Happy #BurnsNight🏴
📷@tomduffinphotos.bsky.social
That's blinkin' in the lift sae hie;
She shines sae bright to wyle us hame,
But, by my sooth, she'll wait a wee!"
Lots of despair & sadness watching the 🇺🇸news today.
I'm hoping Burns can lift your spirit today.
🏴Happy #BurnsNight🏴
📷@tomduffinphotos.bsky.social
Reposted by Sean McMahon
It's been great seeing everyone enjoying the paper and the thread! Just to add:
1 ) It's pronounced "Proto-tax-eye-tees" (not that it would mind being mispronounced)
2 ) Yes it does look like giant penis, but more interesting is that we don't know why or how it got to looking like a giant penis.
1 ) It's pronounced "Proto-tax-eye-tees" (not that it would mind being mispronounced)
2 ) Yes it does look like giant penis, but more interesting is that we don't know why or how it got to looking like a giant penis.
Our paper on the mysterious Devonian organism Prototaxites has now finally been published! See the paper here (www.science.org/doi/10.1126/...) and our explainer thread below!
Prototaxites reconstruction by Matt Humpage
Prototaxites reconstruction by Matt Humpage
January 22, 2026 at 10:12 PM
It's been great seeing everyone enjoying the paper and the thread! Just to add:
1 ) It's pronounced "Proto-tax-eye-tees" (not that it would mind being mispronounced)
2 ) Yes it does look like giant penis, but more interesting is that we don't know why or how it got to looking like a giant penis.
1 ) It's pronounced "Proto-tax-eye-tees" (not that it would mind being mispronounced)
2 ) Yes it does look like giant penis, but more interesting is that we don't know why or how it got to looking like a giant penis.
Reposted by Sean McMahon
Cecilia Payne Gaposchkin’s autobiography is just amazing. Every astronomer should read it.
Here she is talking about her memories of Annie Jump Cannon.
Here she is talking about her memories of Annie Jump Cannon.
January 22, 2026 at 12:30 AM
Cecilia Payne Gaposchkin’s autobiography is just amazing. Every astronomer should read it.
Here she is talking about her memories of Annie Jump Cannon.
Here she is talking about her memories of Annie Jump Cannon.
Great thread on our big new paper about Prototaxites. We set out to investigate whether these iconic (and sometimes huge) fossils were fungi. Not only are they not fungi, they represent a lost lineage of eukaryotes and an independent origin of complex multicellularity. Crazy!
Our paper on the mysterious Devonian organism Prototaxites has now finally been published! See the paper here (www.science.org/doi/10.1126/...) and our explainer thread below!
Prototaxites reconstruction by Matt Humpage
Prototaxites reconstruction by Matt Humpage
January 21, 2026 at 8:50 PM
Great thread on our big new paper about Prototaxites. We set out to investigate whether these iconic (and sometimes huge) fossils were fungi. Not only are they not fungi, they represent a lost lineage of eukaryotes and an independent origin of complex multicellularity. Crazy!
Reposted by Sean McMahon
Reposted by Sean McMahon
a very common problem for autocrats, who assume everyone is secretly like them. I remember Putin being unable to grasp that Bush was not responsible for firing journalists
The Trump disbelief that the Norwegian govt doesn't control the Nobel process is deeply indicative of his thinking. He can't conceive that an institution could (or should) be genuinely independent of coercion or political power. That's the change he represents.
Trump: "I should have gotten the Nobel prize for each war...I saved millions and millions of people...and don't let anyone tell you that Norway doesn't control the shots. It's in Norway. Norway controls the shots. It's a joke. They've lost such prestige.“
January 21, 2026 at 1:06 PM
a very common problem for autocrats, who assume everyone is secretly like them. I remember Putin being unable to grasp that Bush was not responsible for firing journalists
Reposted by Sean McMahon
Yesterday it was cows using tools, today its penguins using satellite imagery.
January 20, 2026 at 6:44 PM
Yesterday it was cows using tools, today its penguins using satellite imagery.
Reposted by Sean McMahon
Ha ha ha ha ha ha ha!!!
Honestly I don’t know whether to laugh or cry at this Orwellian space bullshit.
Putting lipstick on a cosmic space pig about a horribly destructive, wasteful and regressive year at NASA.
🧪🔭
www.nasa.gov/news-release...
Honestly I don’t know whether to laugh or cry at this Orwellian space bullshit.
Putting lipstick on a cosmic space pig about a horribly destructive, wasteful and regressive year at NASA.
🧪🔭
www.nasa.gov/news-release...
NASA Unlocks Golden Age of Innovation, Exploration in Trump’s First Year - NASA
One year into President Donald J. Trump’s second term, NASA is delivering measurable progress across human spaceflight, science, aeronautics, and cutting-edge
www.nasa.gov
January 20, 2026 at 8:27 PM
Ha ha ha ha ha ha ha!!!
Honestly I don’t know whether to laugh or cry at this Orwellian space bullshit.
Putting lipstick on a cosmic space pig about a horribly destructive, wasteful and regressive year at NASA.
🧪🔭
www.nasa.gov/news-release...
Honestly I don’t know whether to laugh or cry at this Orwellian space bullshit.
Putting lipstick on a cosmic space pig about a horribly destructive, wasteful and regressive year at NASA.
🧪🔭
www.nasa.gov/news-release...
Reposted by Sean McMahon
Any one of these daily atrocities should result in a full congressional investigation and a disbanding of the agency. The fact that it’s all just shrugged off by those with the power to stop it is a national disgrace.
ICE ended up returning the man, Saly, after realizing he’s a fucking US citizen with no criminal record, per his sister-in-law. These fucking animals.
January 19, 2026 at 11:58 AM
Any one of these daily atrocities should result in a full congressional investigation and a disbanding of the agency. The fact that it’s all just shrugged off by those with the power to stop it is a national disgrace.
Birds in microgravity are hilarious...
Quails in space
YouTube video by shadeofx3
www.youtube.com
January 18, 2026 at 8:12 PM
Birds in microgravity are hilarious...
Reposted by Sean McMahon
It’s a real shame that Nigel Farage is too unwell to do interviews the morning after Donald Trump threatens us with sanctions.
Here he is with “the bravest man he ever met”. He campaigned to make Trump President, and has spent the last year enjoying all the chaos he has caused.
Here he is with “the bravest man he ever met”. He campaigned to make Trump President, and has spent the last year enjoying all the chaos he has caused.
January 18, 2026 at 10:51 AM
It’s a real shame that Nigel Farage is too unwell to do interviews the morning after Donald Trump threatens us with sanctions.
Here he is with “the bravest man he ever met”. He campaigned to make Trump President, and has spent the last year enjoying all the chaos he has caused.
Here he is with “the bravest man he ever met”. He campaigned to make Trump President, and has spent the last year enjoying all the chaos he has caused.
Reposted by Sean McMahon
Perseverance - Watson Selfie near Sally's Cove - Sol 1500 - From Simeon Schmauß (stim3on.bsky.social) - https://flic.kr/p/2r45L89
January 17, 2026 at 1:00 AM
Perseverance - Watson Selfie near Sally's Cove - Sol 1500 - From Simeon Schmauß (stim3on.bsky.social) - https://flic.kr/p/2r45L89
Reposted by Sean McMahon
wikipedia turns 25 today! the last unenshittified major website! backbone of online info! triumph of humanity! powered by urge of unpaid randos to correct each other! somehow mostly reliable! "good thing wikipedia works in practice, because it sure doesn't work in theory" - old wiki adage
January 15, 2026 at 1:47 PM
wikipedia turns 25 today! the last unenshittified major website! backbone of online info! triumph of humanity! powered by urge of unpaid randos to correct each other! somehow mostly reliable! "good thing wikipedia works in practice, because it sure doesn't work in theory" - old wiki adage
Reposted by Sean McMahon
Deep-sea sponge appreciation post: Bolosoma is a glass sponge that builds vertical structure in the deep sea, creating habitat for a whole host of life. IN 2025 on dives in Papahānaumokuākea, some had heads nearly a meter wide.
📷 NOAA Ocean Exploration, 2025 Beyond the Blue
📷 NOAA Ocean Exploration, 2025 Beyond the Blue
January 15, 2026 at 3:01 PM
Deep-sea sponge appreciation post: Bolosoma is a glass sponge that builds vertical structure in the deep sea, creating habitat for a whole host of life. IN 2025 on dives in Papahānaumokuākea, some had heads nearly a meter wide.
📷 NOAA Ocean Exploration, 2025 Beyond the Blue
📷 NOAA Ocean Exploration, 2025 Beyond the Blue
Reposted by Sean McMahon
New Yorker, by Paul Karasik.
January 15, 2026 at 1:30 PM
New Yorker, by Paul Karasik.
Reposted by Sean McMahon
5 days left to apply for a postdoc job with me, working on Martian glaciation!
Advert: tinyurl.com/6rzzk5d4
Relevant for glaciologists, geomorphologists, ice flow modellers, GIS or deep learning folks.
Closes 19th Jan. Queries via email.
📸HiRISE / @theseaning.bsky.social
Advert: tinyurl.com/6rzzk5d4
Relevant for glaciologists, geomorphologists, ice flow modellers, GIS or deep learning folks.
Closes 19th Jan. Queries via email.
📸HiRISE / @theseaning.bsky.social
January 14, 2026 at 12:41 PM
5 days left to apply for a postdoc job with me, working on Martian glaciation!
Advert: tinyurl.com/6rzzk5d4
Relevant for glaciologists, geomorphologists, ice flow modellers, GIS or deep learning folks.
Closes 19th Jan. Queries via email.
📸HiRISE / @theseaning.bsky.social
Advert: tinyurl.com/6rzzk5d4
Relevant for glaciologists, geomorphologists, ice flow modellers, GIS or deep learning folks.
Closes 19th Jan. Queries via email.
📸HiRISE / @theseaning.bsky.social
🚨New preprint (not peer reviewed)! Last year, NASA announced "potential biosignatures" on Mars: bleached spots in rust-red rocks. Here, we show that rust-dissolving bacteria really can make spots like these. Next step: see if we can make them without bacteria! #astrobiology doi.org/10.64898/202...
January 14, 2026 at 12:48 PM
🚨New preprint (not peer reviewed)! Last year, NASA announced "potential biosignatures" on Mars: bleached spots in rust-red rocks. Here, we show that rust-dissolving bacteria really can make spots like these. Next step: see if we can make them without bacteria! #astrobiology doi.org/10.64898/202...
Reposted by Sean McMahon
Here's some ice I can get behind.
The southern polar cap of Mars, imaged by ESA's Mars Express spacecraft in December 2012.
Much of this ice is frozen CO₂, with some portion of conventional (to us) water ice, too.
The southern polar cap of Mars, imaged by ESA's Mars Express spacecraft in December 2012.
Much of this ice is frozen CO₂, with some portion of conventional (to us) water ice, too.
January 10, 2026 at 11:33 PM
Here's some ice I can get behind.
The southern polar cap of Mars, imaged by ESA's Mars Express spacecraft in December 2012.
Much of this ice is frozen CO₂, with some portion of conventional (to us) water ice, too.
The southern polar cap of Mars, imaged by ESA's Mars Express spacecraft in December 2012.
Much of this ice is frozen CO₂, with some portion of conventional (to us) water ice, too.
Reposted by Sean McMahon
Cotterite is an exceedingly rare form of quartz known from one Irish locality in Co. Cork. I was privileged to be present when Ben (7) brought it into the museum @nmireland.bsky.social Full story just published in Irish Naturalists’ Journal @injournal.bsky.social
www.irishtimes.com/environment/...
www.irishtimes.com/environment/...
Boy (7) strikes it lucky by finding one of the world’s rarest minerals near his home in Cork
Within seconds of handing it over to an expert, it was clear quartz discovery was very special
www.irishtimes.com
January 10, 2026 at 8:11 AM
Cotterite is an exceedingly rare form of quartz known from one Irish locality in Co. Cork. I was privileged to be present when Ben (7) brought it into the museum @nmireland.bsky.social Full story just published in Irish Naturalists’ Journal @injournal.bsky.social
www.irishtimes.com/environment/...
www.irishtimes.com/environment/...