Extremophile survives the transient pressures associated with impact-induced ejection from Mars
TL;DR
Imagine a massive asteroid hitting Mars so hard that it blasts chunks of rock into space - some of these rocks eventually land on Earth as meteorites. Scientists wanted to know: if there were tiny life forms (bacteria) living in those Martian rocks, could they survive the incredible shock of being launched into space? They took one of Earth's toughest bacteria, Deinococcus radiodurans (nicknamed "Conan the Bacterium"), and subjected it to the same crushing pressures that would occur during such an impact. Amazingly, most of the bacteria survived pressures that would instantly crush almost any other living thing. This suggests that life could potentially hitchhike between planets on rocks, surviving the violent journey through space.
Large-scale impacts are ubiquitous in the solar system, and the likelihood of survival of organisms after an impact event plays a key role in planetary protection, the search for extraterrestrial life, and the assessment of the panspermia hypothesis. Impacts generate very high stresses for short times, resulting in extreme pressures and high rates of loading. Can microorganisms survive such extreme conditions? Directly assessing the resilience of microorganisms subjected to impact stresses has been difficult because of challenges in experimental design for these extreme conditions, together with the choices of biological model system. Here, we describe an experimental approach that allows us to subject microorganisms to controlled extreme pressures for short times, recover these impacted microorganisms, and then assess their rates of survival, structural damage, and their molecular response to these extreme events. We focused on Deinococcus radiodurans, an extremophile that is known to survive space-like conditions. Our results suggested that microorganisms can survive much more extreme conditions than previously thought, potentially surviving conditions that result in the formation of ejecta that can move across planetary systems. We demonstrated that the extremophile D. radiodurans has remarkably high survivability and viability after being subjected to pressures of up to 3 GPa. As the pressure increases, D. radiodurans exhibited indicators of increased biological stress, as determined by the transcriptional analysis of impacted samples. The work has significant consequences for considerations of planetary protection, spacecraft mission design, our understanding of where we might find extraterrestrial life, and lithopanspermia.
- 1Deinococcus radiodurans achieved approximately 95% survival at 1.4 GPa impact pressure and 60% survival at 2.4 GPa, which is orders of magnitude higher than other microorganisms such as E. coli and S. oneidensis under similar conditions.
- 2Survival of D. radiodurans follows a power law relationship with pressure (S = 100 - a(P - Pi)^b), with survival predicted to fall below 10^-6 only at pressures reaching approximately 3.1 GPa, exceeding the estimated 0-5 GPa range relevant to Mars ejecta formation.
- 3Transcriptomic analysis revealed that at 2.4 GPa, D. radiodurans upregulated DNA repair, replication, recombination, and mobilome genes while downregulating cell wall biogenesis, energy production, and cell division pathways, indicating prioritization of damage repair over growth.
- 4TEM imaging confirmed that cells impacted at 1.4 GPa retained normal tetrad morphology and intact cell walls, while cells at 2.4 GPa showed ruptured membranes and internal damage consistent with reduced survival.
- 5A modified pressure-shear plate impact experimental approach enabled controlled, uniform, and measurable transient pressures (~1 microsecond duration) to be applied to living microorganisms with sufficient biological material recovery for transcriptomic analysis, representing the first such study of molecular responses to high-velocity impacts.
M87's black hole flipped its magnetic field
Imagine a bar magnet with a north and south pole. Now imagine that magnet suddenly flipping so north becomes south and vice versa. That's essentially what happened with the magnetic field around the giant black hole at the center of galaxy M87 — except this black hole is 6.5 billion times heavier than our Sun. Scientists noticed this flip by watching the powerful beam of energy, called a jet, that shoots out from the black hole. The direction and behavior of that beam changed in a way that revealed the magnetic field had reversed. It's a big deal because those magnetic fields are thought to act like the engine that powers and steers these cosmic jets, and we've rarely caught one flipping in action.
The 2026 World Cup's grass is an engineering problem
Imagine you're trying to play soccer in 16 different places across the United States, Canada, and Mexico — some in freezing cold, some blazing hot, some in stadiums with roofs that block sunlight. Half of those stadiums normally use fake grass. Now FIFA, the organization that runs the World Cup, wants every single pitch to feel and play exactly the same way, like a video game where every level has identical physics. To do that, they hired grass scientists — yes, that's a real job — who figured out how to grow special grass on thin mats with plastic underneath so it can be transported like a carpet, stitched with synthetic fibers so it doesn't rip when players sprint and tackle, and tested by literally shooting balls at it with a cannon to make sure it bounces right. Different grass species are used depending on whether a stadium is hot, cool, or dark. It's basically a giant, living, high-tech floor installation that has to survive the world's best athletes running on it.
Non-Mendelian inheritance of DNA methylation patterns in mice
Imagine your DNA is like a huge book of instructions. Mendel's laws are the normal rules for how chapters of that book get passed from parents to children. But there's also a layer of sticky notes on top of the book—called epigenetic marks—that tell cells which chapters to read and which to ignore. This study found that most of the time (about 93%), these sticky notes follow the normal inheritance rules. But about 7% of the time, they do something unexpected: new patterns appear that neither parent had, or a mark from one parent somehow silences the same mark from the other parent (called paramutation), or males and females end up with completely different sticky notes even when they inherit the same DNA. Scientists discovered this by using a new ultra-precise DNA reading technology in mice, and it opens the door to understanding hidden layers of how traits—and possibly diseases—are passed down through generations.
Remarks on the disproof of the unit distance conjecture
Imagine you scatter a bunch of dots on a piece of paper. The question is: how many pairs of those dots can be exactly 1 inch apart? The Erdős unit distance conjecture asked whether there's a specific mathematical formula that limits how often this can happen as you add more and more dots. Think of it like asking how many friendships can exist in a town where friends are defined as people who live exactly one mile apart — there's a suspected maximum, and Erdős guessed what that maximum should be. For decades, no one could prove or disprove his guess. Now, an AI apparently found a specific arrangement of dots (a 'counterexample') that breaks the expected limit, proving Erdős's conjecture was wrong. A team of elite mathematicians then checked and explained the AI's work in this paper.