The asteroid is unlikely to be cause for concern, but its detection has triggered planetary defence response procedures for the first time

When asteroids like Bennu hit the young Earth, they could have provided a complete package of complex molecules and the ingredients essential to life, such as water, phosphate and ammonia. Together, these components could have seeded Earth’s initially barren landscape to produce a habitable world.

A NASA spacecraft has returned asteroid samples that hold not only the pristine building blocks for life but also the salty remains of an ancient water world.

Rock and dust samples from the Bennu asteroid contain molecules that are the "key to life" on Earth, NASA officials announced on Wednesday.