Wednesday, December 1

Complex molecules could identify extraterrestrial life

Complex molecules could identify extraterrestrial life

Complex molecules could identify extraterrestrial life

Researchers at the University of Glasgow have developed a new method that could revolutionize the search for extraterrestrial life: it stands out because it identifies complex molecular expressions, which can only come from some form of life and not from abiotic sources.

In this way, it eliminates the “false positives” that have significantly slowed down efforts to discover life beyond our planet. Instead of focusing on determining which chemical signatures are unique to life in order to reach a conclusion about the samples, look for molecular complexity: this characteristic is unique to living organisms.

According to a Press release, the system works with samples from all over the planet and with extraterrestrial samples. It has shown that life on Earth can only produce molecules with a high assembly number. Life, consequently, inevitably requires complex molecules.

Molecules and life

The molecules They are an electrically neutral and stable group of at least two atoms, which have a defined configuration and are united through consistent chemical bonds. A molecule can include several atoms of a single chemical element, such as oxygen, or of different elements, such as water.

As components of matter, molecules can be found in organic substances, but they also make up most of the oceans and the atmosphere. At the same time, a large number of known solid substances, such as minerals that can be found in the Earth’s crust, mantle, and core, also have a large number of chemical bonds but are not made up of molecules.

Complex molecules define life

One of the great advances that this new system seems to achieve is to avoid the great dilemma of determining whether a biosignature or biological mark found belongs exclusively to living organisms or, on the contrary, could also come from abiotic sources. In the latter case, it would not be possible to consider it as evidence of a new detected life form.

How can this problem be overcome? According to those responsible for the new study, published in the journal Nature Communications, the mechanism uses the technology called mass spectrometry to divide a molecule into bits and later define the number of unique parts that compose it.

Basically, mass spectrometry is an analysis technique that allows defining the distribution of the molecules of a substance according to their mass. The scientists concluded that the more unique pieces can be identified in a molecule, the greater the chances of confirming its membership in a living organism.

In a concept called measurement of molecular assembly, specialists concentrate on determining the chemical complexity of a sample: they know that life on Earth can only produce molecules with a high number of bonds or bonds or, in other words, molecules characterized by their complexity.

Related topic: Artificial Intelligence can discover extraterrestrial life different from that of Earth

The perfect system to confirm life?

In this way, a more efficient method would be available to analyze extraterrestrial samples and be able to conclude if they coincide with any Lifestyle similar to those known on Earth. The system would even be effective in revealing new forms of artificial life that may have been created, deliberately or by chance, within the framework of scientific work.

Will molecular assembly be the technique that will finally lead us to define the existence of life outside our planet? Or will it be limited by focusing only on known life forms on Earth, leaving out others that we have yet to understand?


Identifying molecules as biosignatures with assembly theory and mass spectrometry. Marshall, S.M., Mathis, C., Carrick, E. et al. Nature Communications (2021).DOI:

Photo: Raphaël Biscaldi on Unsplash.

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