A newly discovered field of glassy “geraisites” in Brazil reveals that a powerful asteroid struck the region around 6.3 million years ago. Spanning more than 900 kilometers, the find ranks among the world’s major tektite fields — even though the crater is still missing. Credit: Shutterstock Scientists have identified Brazil's first known field of tektites, the glassy material created when an asteroid or other extraterrestrial object strikes Earth with extreme force. These newly recognized