Asteroid Bennu is thought to be made of rubble fragments from a 4.5-billion-year-old parent body, containing materials that originated beyond Saturn, which was destroyed long ago in a collision with another object. In two new papers, scientists report the detection of amino acids (including 14 of the 20 used in terrestrial biology), polycyclic aromatic hydrocarbons, ammonia and other compounds, as well as a variety of salts, including sodium carbonates, phosphates, sulfates, and chlorides, in the Bennu samples, which NASA’s OSIRIS-REx spacecraft delivered to Earth in 2023.
“NASA’s OSIRIS-REx mission already is rewriting the textbook on what we understand about the beginnings of our Solar System,” said Dr. Nicky Fox, associate administrator for Science Mission Directorate at NASA Headquarters.
“Asteroids provide a time capsule into our home planet’s history, and Bennu’s samples are pivotal in our understanding of what ingredients in our Solar System existed before life started on Earth.”
In the Bennu samples, the researchers found amino acids — 14 of the 20 that life on Earth uses to make proteins — and all five nucleobases that life on Earth uses to store and transmit genetic instructions in more complex terrestrial biomolecules, such as DNA and RNA, including how to arrange amino acids into proteins.
They also detected exceptionally high abundances of ammonia, which is important to biology because it can react with formaldehyde, which also was detected in the samples, to form complex molecules, such as amino acids — given the right conditions.
When amino acids link up into long chains, they make proteins, which go on to power nearly every biological function.
These building blocks for life detected in the Bennu samples have been found before in extraterrestrial rocks.
However, identifying them in a pristine sample collected in space supports the idea that objects that formed far from the Sun could have been an important source of the…
Read the full article here
