We Have No Robust Evidence of Nucleobases on an Asteroid

 In the science news on the day I am writing this post, we have yet another dubious science-flavored headline. It is a press release talking about an unmanned spacecraft that retrieved a soil sample from an asteroid. We have a headline of "Asteroid Reveals the 5 Key Genetic Ingredients For Life on Earth."  Where to begin on how misleading this claim is? 

(1) Unlike soup, which is made from "ingredients" that can be poured into a soup pot, life cannot arise from non-life by a mere accumulation of the right ingredients. For life to arise from non-life, you need an enormously high level of organization. 

(2) You could never be justified in using the term "genetic ingredients" unless you were talking about a gene, which is a unit of functional information that tells which amino acids make up a particular type of functional protein molecule. No one ever discovered any protein molecule on an asteroid, nor has anyone discovered any gene on an asteroid. 

(3) Just as functional paragraphs are made up of hundreds of well-arranged characters, genes are made up of hundreds or thousands of well-arranged chemical units called nucleobases.  No one has even produced a trustworthy account of nucleobases discovered on an asteroid, in a reliable detection we can trust. All that happened is that some scientists claimed to have discovered some nucleobases in the tiniest trace amounts in a soil sample retrieved from an asteroid, without ever actually having adequate warrant for such a claim. 

The press release follows the rule that all press releases of this type follow: the rule that no mention is ever made of how much of the supposedly discovered chemical was discovered. It almost invariably  turns out that the chemical reportedly found has reportedly been found at some negligible trace amount such as 1 part per billion. The people who write press releases of this type are like people who tell you that money can be found by sifting through the sand at a beach, while failing to tell you that what they mean is maybe 1 penny every 100 meters of sand.  

A look at the scientific paper being promoted by the press release gives us the expected reports of only negligible trace amounts. Figure 3 shows us that the reported total levels of nucleobases is less than 3000 picomoles per gram, which is the same as 3 nanomoles per gram. A picomole is a trillionth of a mole. A gram of ordinary soil has about .2 moles per gram. So if you are analyzing a gram of soil from an asteroid, and find something at a level of less than 3 nanomoles per gram, you are finding an abundance level of roughly 1 part in 100 million. I get that number by typing into Google "3 nanomoles per gram divided by .2 moles per gram," which then gives me an answer of roughly 1 part in 100 million. 

But the fact that the paper reports reports such an abundance level does not mean we should accept that claim uncritically. In investigations such as this, there is the all-important issue of terrestrial contamination. Nucleobases are all over Earth, as nucleobases are in all life, and the planet is teeming with life. In any space mission going from Earth to an asteroid and then returning a soil sample from an asteroid, there would be chances of earthly contamination everywhere. Nucleobases or amino acids might be transmitted from Earth to the asteroid, if there was not a perfect removal of all nucleobases from the spacecraft landing on the asteroid. Or when the soil sample was retrieved and brought back to Earth, nucleobases or amino acids on Earth might get into the soil sample, compromising the analysis. The issue is explained in the infographic below. 

Infographic by Google Gemini

For any scientific paper to credibly report very tiny amounts of nucleobases supposedly found in samples retrieved from an asteroid, there would need to be a thorough discussion of the issue of earthly contamination -- or else the paper should not be taken very seriously.  How much discussion of contamination is there in the the scientific paper being promoted in the press release discussed above?  There is none. The paper does not even use the word "contamination." 

We simply have no reliable evidence here that any nucleobases were discovered on an asteroid. The reported extremely tiny levels of nucleobases (about 1 part in 100 million) are best explained under the idea of earthly contamination. There is no easy way to remove all traces of nucleobases from a spacecraft sent to an asteroid, and no easy way to make sure that earthly nucleobases are kept out of some lab that is analyzing such samples. You can make sure that a spacecraft sent to an asteroid is sterile, by using sterilization techniques that kill all life forms. But nucleobases are not removed by mere sterilization. 

A December 2025 LiveScience article tells us this:

 "Earlier this year, scientists identified more than two dozen previously unknown bacterial species lurking in the Kennedy Space Center cleanrooms in Florida, where NASA assembled its Phoenix Mars Lander in 2007. The discovery showed that despite constant scrubbing, harsh cleaning chemicals and extreme nutrient scarcity, some microbes....persist in these punishing environments."

If entire microbes can exist in such cleanrooms used to prepare spacecraft for biology-related missions and used to analyze samples returned by such spacecraft, how much more likely it is that mere nucleobases would exist in such cleanrooms? Nucleobases are very many times smaller than microbes. It is many times harder to remove all nucleobases from a cleanroom and a spacecraft than to remove all microbes. Nucleobases are everywhere on Earth, and cannot be killed conveniently by simple sterilization methods that kill microbes.  

We simply cannot have any high confidence that the reported detections of tiniest trace amounts of nucleobases in a soil  sample from an asteroid tells us anything about the existence of nucleobases on such an asteroid.  Earthly contamination is the most plausible explanation of these results. Even if such nucleobases existed on an asteroid in such tiniest trace amounts, it would have little significance in explaining life's origin. There would be nothing capable of extracting chemicals in such tiniest trace amounts and concentrating them and usefully arranging them to help make a living thing.  Similarly, the ground of a forest may have here and there a twig or group of twigs that make the characters "I" or "H" or "T." But we know of nothing that could cause characters so rarely appearing on a forest floor to become concentrated and intelligibly arranged to spell out a paragraph of useful text. 

A scientific paper tells us this:

"Mycoplasmas are the simplest cells capable of independent growth in laboratory media...One of those three species, Mycoplasma genitalium, has the smallest genome at 580,076 [nucleobases] (Fraser et al. 1995). It has long been referred to as a minimal or near-minimal cell and used as a surrogate for a minimal cell in many studies. The genes that remain in modern mycoplasmas likely consist of only the minimum number of genes needed for life in their natural habitat."

Don't think for a moment that you can get such a cell by merely accumulating or concentrating about half a million nucleobases of any type. Instead, the nucleobases must all be specially arranged to make the roughly 470 genes in such a cell, each of which is its own separate complex invention, typically consisting of hundreds of well-arranged parts.  The total required amount of very well-arranged functional information is very roughly the same as that required to make a 100-page book. 

But today's science journalists never seem to tell us such things, and instead stupidly speak rather as if getting life from non-life is as easy as dumping the right soup ingredients into a soup pot, failing to understand the organization requirements, kind of like the guy below.