The simplest amino acid, carbamine, can form in the very earliest and coldest phases of star formation. This molecule plays a crucial role in the chain of events that may lead to the emergence of life. The findings were reported in the ACS Center for Science journal.
A central idea in origin-of-life research is that amino acids, the fundamental building blocks of living systems, could arise from reactions in a primordial soup on early Earth. Another idea posits that these compounds were delivered to Earth by meteoritic impacts. Yet the exact locations and conditions under which amino acids form remain uncertain. The new study shows that amino acids can emerge in interstellar ice just as stars and planets are taking shape.
Researchers built models of interstellar ice that contained ammonia and carbon dioxide. They placed these mixtures on a silver substrate and heated them gradually. They observed the formation of carbamic acid and ammonium carbamate beginning at extremely low temperatures, around minus 389 degrees Celsius. This result indicates that the raw materials for more complex amino acids could arise during the very earliest and coldest stages of star formation.
The team also found that at higher temperatures two molecules of carbamic acid can bond, a process compatible with the conditions found in a nascent star. There is a growing consensus that such molecules may have reached Earth through comets or meteorites, contributing to the prebiotic inventory necessary for life.
These insights have practical implications beyond theory. They can help guide the calibration of deep-space instruments, including those aboard the James Webb Space Telescope, to search for life-essential molecules in distant regions of the universe. By understanding where and how these compounds form, scientists refine their search strategies for signs of life beyond our solar system.
In related reflections, scientists have speculated about hidden roles for dark matter on Earth. While this topic remains speculative, the exploration underscores how the cosmos can influence chemistry on our planet and inspire new lines of inquiry in astrochemistry and astrobiology.