Asteroid Bennu sample suggests an ocean world origin

View larger. | A tiny fraction of the asteroid Bennu sample returned by NASA’s OSIRIS-REx mission, shown in microscope images. Top left: A dark Bennu particle, about a millimeter long, with an outer crust of bright phosphate. The other three panels show progressively zoomed-in views of a fragment of the particle that split off along a bright vein containing phosphate, captured by a scanning electron microscope. Image via Lauretta & Connolly et al. (2024) Meteoritics & Planetary Science, doi:10.1111/maps.14227...