Understanding the freezing weather sweeping across the United States — and why Texas’s independent power grid was doomed to fail in its wake. Plus, NASA tries to land a car on Mars. Read more: At least 14 people are dead in four states after a record-breaking cold snap swept through parts of the United States. Meteorologist Matthew Cappucci explains the science behind the freezing temperatures — and why the country might be bracing for more. Will Englund reports on how the Texas power grid got crushed because its operators weren’t prepared. NASA’s Mars rover, Perseverance, could be in for a bumpy landing Thursday. But if it survives the “seven minutes of terror,” Perseverance could hold the key to future exploration of the Red Planet.