Earth and Life: A Four Billion Year Conversation by Andrew H. Knoll

Andrew H. Knoll

Next week, March 31st at 6:00 pm EDT, head to the Harvard Geological Museum to hear Andrew H. Knoll discuss his new book, Earth and Life: A Four Billion Year Conversation. He will be in conversation with @rdword.bsky.social.

RSVP is required for this free, in-person event: buff.ly/8Qm7Ahz

It depends on the leader in charge but currently, very much so.

‘We defeated the parties of billionaire donors’: Hannah Spencer’s victory speech ‘We don’t have to fight dirty to fight for change,’ says Green party’s new MP after Gorton and Denton byelection win

www.theguardian.com/politics/202...

It's inspiring to see this result and speech from the Green party in the UK today!

NASA Decadal Astrobiology Research and Exploration Strategy - NASA Science The NASA Astrobiology Strategy from 2015 has been an excellent document for NASA planning and advancement of astrobiology. In the past 10 years, the National

NASA Decadal Astrobiology Research and Exploration Strategy (DARES) community webinars are starting this week! Please join if you're interested in contributing to NASA's next astrobiology roadmap.

Sign-up link is here: science.nasa.gov/astrobiology...

You can't... repeal... a scientific finding. At that point it's just called lying about it.

Save NCAR from being dismantled today! The Trump Administration has vowed to dissolve the center that provides critical extreme weather and climate data for our nation.

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

Search for Life Should Be Top Science Priority for First Human Landing on Mars, Says New Report When astronauts set foot on Mars, it will be one of humanity’s greatest milestones, marking the start of a new era of discovery on another planet. A new National Academies report identifies the highes...

I'm a day late with this because I was at the National Academies for this briefing. The big takeaway is that the search for life should be the top science priority when we send humans to land on #Mars! 🪐🧪🔭 #Astrobiology www.nationalacademies.org/news/search-...

U.S. Congress considers sweeping ban on Chinese collaborations Researchers speak out against proposal that would bar funding for U.S. scientists working with Chinese partners or training Chinese students

This is lunacy. The Chinese scholars I know are among the hardest working, most selfless people I've ever encountered. They want to contribute to our intellectual endeavors, and they make our research teams better.

Twin spacecraft are set to take off on an unprecedented, winding journey to Mars, where they will investigate why the barren red planet began to lose its atmosphere billions of years ago.
https://cnn.it/49FLkR0

A personal reflection on the destructive erosion of ethics, norms and respect for law at NASA:
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Atmospheric collapse and re-inflation through impacts for terrestrial planets around M dwarfs Detection of an atmosphere around a terrestrial exoplanet will be a major milestone in the field, but our observational capacities are biased towards to tidally locked, close-in planets orbiting M-dwa...

New paper on arxiv led by Prune August on rocky exoplanet atmospheric reinflation! All comments welcome

arxiv.org/abs/2510.25896

My new essay on the future of life in space just appeared in Noema magazine! Kudos to Satwika Kresna for the lovely artwork.

www.thecrimson.com/article/2025...

This is good news for US higher education, although far from the end of the story.

Update on the atmosphere vs no atmosphere debate for TRAPPIST-1 b and c -- here's a nice and (IMO) conclusive result from Gillon and Ducrot et al.: no thick atmosphere on either planet. arxiv.org/pdf/2509.02128

Group photo of postdocs conducting research at a Max Planck Institute

The #MaxPlanckPostdocProgram offers a guaranteed contract of at least 3 years, targeted mentoring, and career workshops. The call for applications is open now! 🚀 Take advantage of this opportunity and browse the job vacancies. www.mpg.de/en/max-planc...

An image of the speaker, Laura Schaefer. She is smiling and looking into the camera. She is wearing a purple-grey zip-up jumper and sunglasses on her head. She is against a background of a large rock with some grass visible near the bottom, clearly outdoors.

An artistic conception of early Earth showing the planet's surface impacted by asteroids. Earth is shown with partial oceans and the land that is visible is covered in clear craters. Part of the Earth (bottom left) is also shown as covered by lava or a magma ocean. Image credit: Simone Marchi, NASA. Taken from https://www.scientificamerican.com/article/early-earth-s-atmosphere-was-surprisingly-thin/

#RockyWorldsDiscussion is back from our summer break! 🔭🧪

Our next speaker is Laura Schaefer from Stanford University, who will tell us about redox gradients in planet formation simulations of terrestrial planets 🌍🌕🪨 Join us on Zoom on Thu 4 Sep @ 16:00 UTC

More: www.rockyworlds.org/event-detail...

yes, collision broadening is included

Cool, thanks for sharing!

What does a molecule sound like? We all learn in high school chemistry or earlier that atoms can bind together to form molecules, and like a " highly sophisticated interlock...

🧪 I'm a fan of this way of interacting with vibrational spectra. I did this on my blog a while ago: nanoscale.blogspot.com/2015/06/what...

If you could hear in the infrared, what would CO2 sound like? We calculated this recently for a Gen Ed course, and the result is a little eerie.

Results were generated by mapping IR frequency in inverse cm to sound frequency in Hz.

U.S. Pulls Back from Quest to Confirm Cosmic Inflation Researchers hoped CMB-S4, a $900-million cosmology experiment, would answer one of the greatest questions in physics. Instead it’s become another cautionary tale of pursuing big science amid shrinking...

Now on @sciam.bsky.social, by @nadiadrake.bsky.social:

The U.S. has axed CMB-S4, its boldest cosmology experiment in generations. Tight budgets and crumbling infrastructure helped doom the project, which was meant to test cosmic inflation. RIP.

www.scientificamerican.com/article/u-s-...

Ancient rocks show earliest evidence of tectonic activity on Earth The origins of plate tectonics on Earth are hotly debated, but evidence from Australia now shows that parts of the crust moved in relation to each other as early as 3.5 billion years ago

Direct evidence for tectonics (of some kind!) 3.5B years ago. The timeline keeps moving back. Nice find by @alexwilkins.bsky.social at Goldschmidt.

Bioplastic habitats on Mars could be built from algae A lab experiment that simulated Mars conditions showed that green algae can grow in plastic containers made from the same algae, setting the stage for a self-sustaining system to build habitats on the planet

A lab experiment that simulated Mars conditions showed that green algae can grow in plastic containers made from the same algae, setting the stage for a self-sustaining system to build habitats on the planet.

Thanks! Our simulations aren't quite in the same regime as Venus, but we separately used the model to recreate Venus's temperature profile and it did pretty well. We found it was right on the edge of convective instability in Venus's lower atmosphere, interestingly.

Convective shutdown in the atmospheres of lava worlds Atmospheric energy transport is central to the cooling of primordial magma oceans. Theoretical studies of atmospheres on lava planets have assumed that convection is the only process involved in setti...

On a related note, we found that convective shutdown by the same mechanism can drastically shorten primordial magma ocean freeze-out times, though with enough irradiation there can be persistent magma oceans despite convective shutdown. arxiv.org/abs/2412.11987

I mean yeah pretty worried, of course : ). The problem with the continuum in the visible is that we need really long path lengths and/or sensitive measurements, which means $$$ for experiments. Maybe ab initio can help, although H2O is a tough molecule to simulate.

New work led by Jess Cmiel finds that planets with steam atmospheres may be cooler — much cooler — at the surface than we previously thought.



iopscience.iop.org/article/10.3...

arxiv.org/abs/2505.00775

This supports and extends conclusions published last year by Selsis et al. in Nature. 🔭 🧪

ROCKY WORLDS 4 - Abstract Submission Abstract submission & conference registration Abstract submission and conference registration are done in two steps. First, the abstract submission below (including requests for financial support) run...

The abstract submission for Rocky Worlds 4 is now open! groningen2026.rockyworlds.org/registration... 🌋🔭🧬😱

The resurfacing is very episodic but it’d still be pretty bad in a period of peak activity. Then in the good times you’d have slimy microbial mats as far as the eye could see. No skyr or harðfiskur, unfortunately.

It's a fascinating question. Global temperature matters a lot, but so do other factors like total area and latitude (equatorial LIPs weather fastest due to higher rainfall rates). If e.g. Brazil was turned into a LIP today, that could well trigger a Snowball.