What happened to the asteroid that hit the dinosaurs?
It was mostly destroyed in the impact, vaporising and melting. It left a huge crater, now buried under Mexico, and a thin layer of dust around the world.
About 66 million years ago, an asteroid about 10 kilometres across, or perhaps a little more, smashed into Earth at what is now the Yucatán Peninsula in Mexico. It was travelling at tens of kilometres per second.
What happened to the asteroid? It did not survive as a big lump. The impact released so much energy that the asteroid almost completely vaporised and melted, along with a huge amount of Earth rock. A tiny fragment, about 2.5 millimetres, thought by some scientists to be a piece of it, was reported in 1998 from sea-floor sediment in the Pacific Ocean, but almost nothing of the asteroid survives.
The crater. The impact made the Chicxulub crater, about 180 kilometres across. Today it is buried under hundreds of metres of younger rock and sea. Scientists found it in the 1970s to 1990s using gravity measurements, magnetic surveys and drilling.
The dust layer. Vaporised asteroid and rock spread around the world and settled as a thin layer of clay. This layer contains a lot of iridium, a metal common in asteroids but rare in Earth's crust. Finding this layer in 1980 helped scientists suspect an asteroid impact.
What it was made of. Studies of the clay layer suggest the asteroid was probably a carbonaceous chondrite, a dark, carbon-rich kind of space rock.