Identifying molecules as biosignatures with assembly theory and mass spectrometry

Area of Science:

• Astrobiology
• Chemistry
• Biophysics

Background:

• The search for extraterrestrial life is hindered by the lack of universally recognized biosignatures.
• Identifying unique indicators of life is crucial for developing effective detection methods.

Purpose of the Study:

• To establish a universal biosignature based on molecular complexity.
• To introduce a novel, experimentally tractable measure of molecular complexity: the molecular assembly index (MA).

Main Methods:

• Calculated the molecular complexity of millions of molecules.
• Validated experimental tractability of MA using mass spectrometry.
• Applied MA to diverse samples from Earth, space, and laboratory settings.

Main Results:

• Demonstrated that complex molecules in high abundance serve as universal biosignatures.
• Validated mass spectrometry as a method to experimentally determine molecular complexity (MA).
• Successfully identified molecular biosignatures in diverse sample types.

Conclusions:

• The molecular assembly index (MA) provides a viable foundation for extraterrestrial life detection experiments.
• MA can serve as a complexity scale to guide prebiotic chemistry research in the laboratory.
• This approach is vital for both discovering life beyond Earth and creating synthetic life in labs.