Merry Christmas, friends

Saturn's tiny icy moon Mimas hangs in space against a backdrop of the giant planet itself. The rings cross the bottom of the view, and cast their shadows onto the planet beyond. NASA Photojournal PIA06142, taken by the Cassini spacecraft on 7 November 2004 some 3.7 million km from Saturn.

This day 57 years ago. Earthrise. A remarkable view of Earth hoving into view as the Apollo 8 command module flew over the lunar surface. That's us. That's home.

Saturn's tiny icy moon Mimas hangs in space against a backdrop of the giant planet itself. The rings cross the bottom of the view, and cast their shadows onto the planet beyond. NASA Photojournal PIA06142, taken by the Cassini spacecraft on 7 November 2004 some 3.7 million km from Saturn.

As we wrap up the year, I'm sharing an achievement I'm particularly proud of—we published the second book in our Comparative Planetology series! Planetary Tectonism deals with the stresses that shape planets and the landforms that develop. It follows Planetary Volcanism, published in 2021.

Some new pics of Mars from ESA's Mars Express have been processed by @andrealuck.bsky.social, including this one showing its moon Phobos hanging in space over the planet surface. It's absurdly sci-fi looking, so I added a Star Destroyer and 80s starfield.

Some new pics of Mars from ESA's Mars Express have been processed by @andrealuck.bsky.social, including this one showing its moon Phobos hanging in space over the planet surface. It's absurdly sci-fi looking, so I added a Star Destroyer and 80s starfield.

As we wrap up the year, I'm sharing an achievement I'm particularly proud of—we published the second book in our Comparative Planetology series! Planetary Tectonism deals with the stresses that shape planets and the landforms that develop. It follows Planetary Volcanism, published in 2021.

Tory Bruno has left ULA for other opportunities. John Elbon is in charge for now.

Jezero Crater, Mars. Thursday. Composite Perseverance rover Right Mastcam-Z camera images taken Thursday, 18 December 2025 at a local time of just before noon. Colour and brightness adjusted to better match human vision. Credit: NASA/JPL-Caltech/ASU/Paul Byrne

On the winter solstice, the Sun rises and shines down the length of the 5,100-year-old Newgrange passage tomb in County Meath, Ireland. Remarkable designing and implementation by the Neolithic engineers who built it.

I hope it fucking hurts

Jezero Crater, Mars. Thursday. Composite Perseverance rover Right Mastcam-Z camera images taken Thursday, 18 December 2025 at a local time of just before noon. Colour and brightness adjusted to better match human vision. Credit: NASA/JPL-Caltech/ASU/Paul Byrne

On the winter solstice, the Sun rises and shines down the length of the 5,100-year-old Newgrange passage tomb in County Meath, Ireland. Remarkable designing and implementation by the Neolithic engineers who built it.

My god. It's full of stars. This sparkling #JWST stellar scene is Westerlund 2, a young star cluster only a few million years old and containing some of the hottest, most massive stars known. Westerlund 2 is situated within the Gum 29 stellar nursery, and is around 20,000 lightyears from home.

My god. It's full of stars. This sparkling #JWST stellar scene is Westerlund 2, a young star cluster only a few million years old and containing some of the hottest, most massive stars known. Westerlund 2 is situated within the Gum 29 stellar nursery, and is around 20,000 lightyears from home.

Disappointing that its sports teams

The name "Popular Science" doesn't mean we shift our coverage depending on public opinion. It means we cover relevant subjects that are rigorously researched, reliable, and grounded in reality. And trans lives are grounded in reality. We see y'all. No matter what. www.popsci.com/science/tran...

At an @agu.org Town Hall today, @ncar-ucar.bsky.social President Antonio Busalacchi spoke to #AGU25 attendees about what's at stake if NCAR is dismantled. One attendee asked anyone who uses NCAR research to stand up. Almost everyone in the room stood. Read more here: eos.org/research-and...

Jared Isaacman has been sworn in as NASA Administrator. www.nasa.gov/news-release...

Europa Clipper has observed interstellar comet 3I/ATLAS with its ultraviolet spectrograph instrument! News here: www.swri.org/newsroom/pre...

🚨 SAVE THE DATE 🚨 We're putting together a Planetary Science Community Meeting at the Kentucky Science Center in Louisville, KY on April 14–16 2026. This is a grass-roots meeting for planetary scientists to gather, discuss, and organize to address pressing issues our community faces. (1/2)

He's giving this speech with all the enthusiasm of me giving an oral report on the economy of Brazil in 9th grade global studies.

Trump Announces 5,000% Increase In All Numbers

Another proud advisor moment as Henry Dawson presents his work on the tectonic states of icy satellite seafloors! tl;dr there might not be very much going on at the ocean floors of many of these moons...

AGU petition to save NCAR. Please share widely! agu.quorum.us/campaign/151...

Joe Neguse, who represents Boulder in Congress, tells #AGU25 that "I am not going to let [the dismantling of #NCAR] take place on my watch...we're exploring every legal option available to us." Says he is working across the aisle for a bipartisan solution.

🚨 SAVE THE DATE 🚨 We're putting together a Planetary Science Community Meeting at the Kentucky Science Center in Louisville, KY on April 14–16 2026. This is a grass-roots meeting for planetary scientists to gather, discuss, and organize to address pressing issues our community faces. (1/2)

NASA has its 15th Administrator. He has a big job ahead of him. Good luck, Jared Isaacman!

Here's our reporting on the proposed dismantling of the jewel of US atmospheric science, @ncar-ucar.bsky.social. The plan is to break NCAR apart and disburse some parts to other locations (like the research aircraft fleet) and eliminate others. www.nature.com/articles/d41... 🧪 #AGU25 #climate

Stay tuned.

Another proud advisor moment as Henry Dawson presents his work on the tectonic states of icy satellite seafloors! tl;dr there might not be very much going on at the ocean floors of many of these moons...

When do we impeach, try, and imprison Russell Vought, a person who has demonstrably shown an utter disdain for the things that *actually* make America great?

Walked once from the planetary sessions to the poster hall #AGU25

Attendance at US-based science conferences is bouncing around this year but generally down. #AGU25 has ~10k fewer this year! I explored these trends for @nature.com — including solutions to keep conferences local & productive: www.nature.com/articles/d41... 🧪

Shout-out to @alexwitze.bsky.social for being included in @merriam-webster.com's definition for "heliophysics" (which has long been a word, but is now a *recognised* word)

Super proud of my grad student Lauren Wratchford, who crushed her #AGU25 talk this morning on comparing tectonics on Venus to collisional zones on Earth!

This is not encouraging. My thoughts are with the MAVEN science and engineering teams as they work to restore contact with, and control of, the spacecraft. science.nasa.gov/blogs/maven/...

Hellloooooooooo New Orleans! #AGU25

Hellloooooooooo New Orleans! #AGU25

Friday, 12 December 2025. Jezero Crater, Mars.

Friday, 12 December 2025. Jezero Crater, Mars.

For fuck's sake. When will this end? apnews.com/article/brow...

I work at WashU. I have never, not once, heard any student, faculty member, or administrative staff say *a single* good thing about Workday. It has made my job harder, and previously simple tasks substantially more complicated. All for $266 million, and counting.

A total solar eclipse. By Earth. Taken from the Moon in March this year.

Top: Sunset on Mars (Curiosity rover, April 2015) Bottom: Sunset on LV-426 (Alien, 1979)

A total solar eclipse. By Earth. Taken from the Moon in March this year.

Top: Sunset on Mars (Curiosity rover, April 2015) Bottom: Sunset on LV-426 (Alien, 1979)

lmao

I would like the phrase and concept of "common decency" to make a comeback