NASA and European scientists explain how they calculate the probability of the space rock 2024 YR4 impacting our planet, and why it’s not yet time to worry. NASA and European scientists explain how they calculate the probability of the space rock 2024 YR4 impacting our planet, and why it’s not yet time to worry. Asteroids, Earth, Space and Astronomy, National Aeronautics and Space Administration, European Space Agency, Jet Propulsion Laboratory, Research, Accidents and Safety NYT > Science