Scientists find evidence that an asteroid contains tryptophan

Tryptophan, the essential amino acid behind the Thanksgiving myth that eating turkey can make you sleepy, has been found to exist on Bennu, a small asteroid that swings by our planet about every six years.

The discovery stems from an unprecedented sample collected by NASA’s OSIRIS-REx mission, which landed a spacecraft on the asteroid in 2020, captured 4.3 ounces (121.6 grams) of rocks and dust, and safely returned the cache to Earth in 2023. NASA has since distributed a small portion of that sample to researchers around the world to be analyzed.

Studying Bennu is important because its composition reflects that of the early solar system, giving scientists a glimpse into the beginnings of life. Previous research on Bennu samples had already found 14 of the 20 amino acids all living or