How did life originate? Did it form on Earth or elsewhere in the solar system and was it seeded on Earth by impact of an asteroid? Will life eventually be wiped out by an asteroid? While we may never know the answers to these questions, scientists are attempting to study as much as possible about the origins of life and the possibilities of future asteroid collisions with the Earth.
NASA’s OSIRIS-REx mission was the first U.S. spacecraft to collect a sample from an asteroid and return it to Earth. The asteroid chosen for this mission was Bennu, a near Earth asteroid rich in carbon. Bennu is a primitive asteroid, meaning it formed when the solar system formed and has changed very little since then.
The spacecraft was launched in 2016, took two years to arrive, orbited Bennu for about 2.5 years, collected a sample in 2020 and then returned to near Earth in 2023, when the spacecraft released a capsule that landed in the Utah desert. The samples are still being studied, and in fact a fraction of the samples will be preserved long term to allow for better technology to perhaps discover something that we are currently incapable of discovering right now.
Bennu samples contain 18 of the 20 amino acids that make up proteins, the components of DNA, phosphates, and sugars. It once hosted liquid water, as indicated by the presence of brine and clays, and it curiously contains a gum-like substance. While no direct evidence of life was found, these findings suggest that the conditions for the emergence of life were widespread across the early solar system.
At the January American Astronomical Society’s meeting in Phoenix, Arizona, Daniella Della-Giustina from the University of Arizona gave the first plenary talk about OSIRIS-REx results and the future mission, OSIRIS-APEX. She concluded in her talk that, “Bennu shows us that complex organic chemistry didn’t require planets or long-lived oceans. It happened early, on small bodies – and those bodies were capable of delivering those ingredients to the Earth.”
The OSIRIS mission will continue its study of asteroids. A new mission called OSIRIS-APEX will reuse the spacecraft to fly by asteroid Apophis. Apophis is an asteroid about 1200ft wide that will pass remarkably close to Earth in April 2029. It will approach to 32,000km, less than 1/10th the distance to the Moon, becoming visible to the naked eye at certain locations on Earth. Have no fear: this asteroid poses no threat of impact. The OSIRIS-APEX spacecraft will study Apophis and attempt to view any changes to the asteroid’s surface as it experiences strong tidal forces due to its proximity to the Earth. It will provide key data for understanding potentially hazardous asteroids to enhance our planetary defense.