The head of planetary defense at the European Space Agency discusses 2024 YR4, an asteroid with a small chance of striking Earth eight years from now.

Scientists say the threat of a newly discovered asteroid has risen slightly in the past few weeks, as the world's telescopes rush to track its course.

YR4 has a roughly 2 percent chance of hitting Earth in 2032, and “is large enough to cause localized damage,” NASA says.