Universe makes us happy, quite literally: NASA finds ‘Happy Hormone’ molecule in asteroid Bennu

Samples from asteroid Bennu have once again been shown to have the essential building blocks of life on Earth. Turns out, humans feel happy because sometime in our planet's past, an asteroid carrying amino acids, genetic molecules, and more, slammed into our planet. Researchers from NASA and the University of Arizona may have, for the first time, detected tryptophan in Bennu samples. Tryptophan is one of the nine essential amino acids that the human body cannot make. It is responsible for creating important brain chemicals like serotonin, which is also known as the "happy hormone". It regulates mood, sleep, digestion, and other bodily functions, and a lack of it can cause depression. If the discovery is confirmed, this would be the first time that tryptophan has ever been found in an extraterrestrial sample.

A team of researchers from NASA's Goddard Space Flight Center, wrote, "Our findings expand the evidence that prebiotic organic molecules can form within primitive accreting planetary bodies and could have been delivered via impacts to the early Earth and other Solar System bodies, potentially contributing to the origins of life." The latest finding, published in the Proceedings of the National Academy of Sciences, further cements the belief that primitive asteroids and comets seeded life on Earth.

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Faint signal for tryptophan detected in Bennu

The team, led by geochemist Angel Mojarro, studies the material to understand the chemical reaction pathways by which the amino acids may have formed, billions of years ago. They tested Bennu samples for the 20 amino acids that build protein in the body. They found several non-biological amino acids and nucleobases, confirming they were of extraterrestrial origin. The team confirmed 14 amino acids found in previous studies, and were surprised when they picked up hints of a faint signal for tryptophan.

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NASA's OSIRIS-REx mission landed on asteroid Bennu in 2018 and, in 2020, collected a fistful of its surface material, locking it in a capsule, which detached from the main spacecraft and returned to Earth in September 2023. Since then, scientists have been studying the Bennu samples and have made several discoveries.

Earlier studies of samples gathered from Bennu and asteroid Ryugu have revealed the presence of extensive inventories of amino acids and nucleobases (the basic units that make up RNA and DNA). Ryugu has been found to have only one nucleobase, Bennu samples surprisingly carried all five common nucleobases - adenine (A), guanine (G), cytosine (C), thymine (T), and uracil (U).