Is it finally time to cue up the Bowie? Or was the NASA presser on Wednesday announcing new findings of potential Martian biosignatures from Perseverance just another in a long line of “We are not alone” teases that turn out to be false alarms? Time will tell, but from the peer-reviewed paper released simultaneously with the news conference, it appears that biological activity is now the simplest explanation for the geochemistry observed in some rock samples analyzed by the rover last year. There’s a lot in the paper to unpack, most of which is naturally directed at planetary scientists and therefore somewhat dense reading. But the gist is that Perseverance sampled some sedimentary rocks in Jezero crater back in July of 2024 with the SHERLOC and PIXL instruments, extensive analysis of which suggests the presence of “reaction fronts” within the rock that produced iron phosphate and iron sulfide minerals in characteristic shapes, such as the ring-like formations they dubbed “leopard spots,” and the pinpoint “poppy seed” formations.

The big deal with these redox reactions is that they seem to have occurred after the material forming the rock was deposited; in other words, possibly by microorganisms that settled to the bottom of a body of water along with the mineral particles. On Earth, there are a ton of aquatic microbes that make a living off this kind of biochemistry and behave the same way, and have been doing so since the Precambrian era. Indeed, similar features known as “reduction haloes” are sometimes seen in modern marine sediments on Earth. There’s also evidence that these reactions occurred at temperatures consistent with liquid water, which rules out abiotic mechanisms for reducing sulfates to sulfides, since those require high temperatures.

Putting all this together, the paper’s authors come to the conclusion that the simplest explanation for all their observations is the activity of ancient Martian microbes. But they’re very careful to say that there may still be a much less interesting abiotic explanation that they haven’t thought of yet. They really went out of their way to find a boring explanation for this, though, for which they deserve a lot of credit. Here’s hoping that they’re on the right track, and that we’ll someday be able to retrieve the cached samples and give them a proper lab analysis here on Earth.

Back here on Earth, the BBC has a nice article about aficionados of old-school CRT televisions and the great lengths they take to collect and preserve them. Thirty-odd years on from the point at which we switched from CRT displays and TVs to flat-panel displays, seemingly overnight, it’s getting harder to find the old tube-based units. But given that hundreds of millions of CRTs were made over about 60 years, there’s still a lot of leaded glass out there. The story mentions one collector, Joshi, who scored a lot of ten displays for only $2,500 — a lot for old TVs, but these were professional video monitors, the kind that used to line the walls of TV studio control rooms and video editing bays. They’re much different than consumer-grade equipment, and highly sought by retro gamers who prize the look and feel of a CRT. We understand the sentiment, and it makes us cringe a bit to think of all the PVMs, TVs, and monitors we’ve tossed out over the years. Who knew?

And finally — yeah, a little short this week, sorry — Brian Potter has another great essay over at Construction Physics, this time regarding the engineering behind the Manhattan Project. What strikes us about the entire effort to produce the first atomic bombs is that everyone had a lot of faith in the whole “That which is not forbidden by the laws of physics is just an engineering problem” thing. They knew what the physics said would happen when you got just the right amount of fissile material together in one place under the right conditions, but they had no idea how they were going to do that. They had to conquer huge engineering problems, turning improbable ideas like centrifugal purification of gaseous uranium and explosive assembly with shaped charges into practical, fieldable technologies. And what’s more, they had to do it under secretive conditions and under the ultimate in time constraints. It’s an interesting read, as is Richard Rhodes’s “The Making of the Atomic Bomb,” which we read back in the late 1980s and which Brian mentions in the essay. Both are highly recommended for anyone interested in how the Atomic Age was born.