NASA's Curiosity rover has found organic molecules on Mars that may be billions of years old

[Bayard]

NASA's Curiosity rover has found organic molecules on Mars that may be billions of years old — and the scientists studying them are being careful about what they say next. Thirteen years after landing in Gale Crater, NASA's Curiosity rover has produced what may be its most significant scientific result to date.

Thirteen years after landing in Gale Crater, NASA’s Curiosity rover has produced what may be its most significant scientific result to date. In a paper published in Nature Communications in April 2026, researchers led by Amy Williams, an astrobiologist and professor of geological sciences at the University of Florida, reported the detection of more than 20 organic molecules in a single Martian rock sample — the most diverse collection ever found on the planet. Seven of the molecules had never been confirmed on Mars before.

The findings have generated substantial coverage, most of it accurate. Some of it has also required the scientists involved to do something that researchers in this field have learned to do carefully: explain, repeatedly and in precise terms, what the discovery does and does not mean.

The experiment at the centre of the April findings used a chemical called tetramethylammonium hydroxide, or TMAH — a solvent capable of breaking apart large organic molecules into smaller fragments that Curiosity’s onboard instruments can then identify. The rover carries only two cups of this chemical. The decision about where to use the first cup was not made lightly.

The chosen sample, drilled from a site the team named Mary Anning 3 — after the 19th-century British paleontologist who spent her career finding fossils others had overlooked — came from the Glen Torridon region of Gale Crater, an ancient clay-rich area that scientists believe once held standing water. The clay minerals there are known to preserve organic material over geological timescales. The sample itself is estimated to be approximately 3.5 billion years old.

“This experiment’s never been run before on another world,” Williams told AFP. The team had two chances to get it right. They used the first one here.

https://spacedaily.com/n-nasas-curiosity-rover-has-found-organic-molecules-on-mars-that-may-be-billions-of-years-old-and-the-scientists-studying-them-are-being-careful-about-what-they-say-next

This material may be lost forever because in Jan. 2026, the rethuglican Congress canceled Mars Sample Return program.

[eppur_se_muova]

1. Breakdown products -- the same products can come from many different sources.

What the TMAH dissolved and released included nitrogen-bearing organic compounds, sulfur-bearing molecules including benzothiophene — previously found in meteorites and asteroids — and a range of carbon-containing structures that, on Earth, are associated with the chemistry of living systems. Among them was a molecule structurally similar to precursors of DNA. The results were verified on Earth by exposing a piece of the Murchison meteorite, a well-studied 4-billion-year-old rock containing organic chemistry, to the same TMAH process. It produced similar breakdown products, including benzothiophene, lending confidence to the Martian readings.

I hope they're more convincing than benzothiophene. Heat almost any hydrocarbon with sulfur hot enough, and you'll get some benzothiphoene. It doesn't mean benzothiophene, or even the branched eight-carbon skeleton of benzothiophen, was present in the sample. It means there were enough carbon, hydrogen, and sulfur atoms that when you cooked them all up and allowed them to re-form into stable molecules, the very stable benzothiophen was some of what resulted. I hope people appreciate what very indirect evidence this is -- the same results could have come from an endless variety of starting points.

Seven of the molecules had never been confirmed on Mars before.

They still haven't. We have only confirmed that Mars contains materials that, forced to decompose and recombine, can form these materials. This is a completely separate question from whether these compounds were originally present, and they almost certainly weren't.

Scientists who search desperately for life where it's not known to exist sometimes seem to be on a religious crusade, and every sign from above only confirms their faith. Maybe someday they'll prove right in one particular instance, but they'll want you to forget all the other unsupported claims that preceded it.

[Figarosmom]

2. Why would they cancel the program

When they want to go there? Wasn't it musk that wants to live on Mars? Congress must not have asked him first when he was in charge.

[dickthegrouch]

3. It's so much more fun going somewhere you know nothing about!

And they can always claim plausible deniability if something on Mars actually bites an astronaut after arrival.

[NNadir]

4. The list of compounds definitively identified as well as NIST matches without retention time matches, reported in S1...

...don't strike me as biogenic; they're mostly aromatics hardly functionalized other than with alkyl groups.

This is not quite as dramatic as say the Murchison meteorite to which they refer repeatedly.

It's an interesting finding, in a geochemical sense, but not all that surprising.

Naphthalene is often identified in interstellar space, for example.

I hold in a wholly speculative way based only on a very superficial reading, that molecular biology originated in space where it strikes me chirality might arise because of asymmetric radiation fields. From what I can recall from my readings on the Murchison meteorite, which probably goes back more than a decade, it did exhibit some asymmetric amino acids, a remarkable finding.

This is cool, but won't keep me up at night.