Asteroid Bennu: A Cosmic Grocery Store for Life's Ingredients
Scientists have discovered tryptophan, an essential amino acid, in samples from asteroid Bennu. This finding adds to the growing evidence that asteroids may have delivered crucial ingredients for life to Earth.
Bennu: A Time Capsule from the Early Solar System
- Size: About one-third of a mile wide
- Origin: Likely broke off from a larger asteroid between 2 billion and 700 million years ago
- Current Location: Orbits close to Earth, visiting every six years
Bennu's samples, collected by NASA's OSIRIS-REx mission in 2020 and returned to Earth in 2023, contain a treasure trove of information about the early solar system.
Life's Building Blocks Found in Bennu
- Amino Acids: 15 out of 20 essential for life on Earth, including the recently discovered tryptophan
- Nucleobases: All five biological nucleobases, the letters that make up DNA and RNA
Tryptophan is particularly significant because it is one of the more complex amino acids and had never been found in space samples or meteorites before.
The Origin of Bennu's Material
- Supernovas: Explosions of old stars created the elements found in Bennu
- Ammonia: Present in Bennu, which can help form molecules like amino acids
- Minerals: Various types found in Bennu
The Role of Asteroids in the Origin of Life
Scientists believe that asteroids like Bennu could have delivered essential ingredients to Earth, making it easier for life to start. However, more tests are needed to confirm the presence of tryptophan in the Bennu samples.
The Significance of the Discovery
The discovery of tryptophan in Bennu shows that many of the building blocks of life can be produced naturally within asteroids or comets. This finding expands the list of amino acids that are produced in space and could have been delivered to Earth.
