237: Why does an asteroid hit the Earth? And why so big?
By Alex Alishevskikh - 2013 Chelyabinsk Meteor Trail, CC BY-SA 2.0, https://commons.wikimedia.org/w/index.php?curid=24726667
A question from Lyla, age 5. Dr. Federica Spoto answers. For more on Dr. Spoto’s work, see episode 190.