On April 13, 2029, a speck of light will streak across the sky, getting brighter and faster. At one point it will travel more than the width of the full Moon within a minute and it will get as bright as the stars in the Little Dipper. But it won’t be a satellite or an airplane—it will be a 1,100-foot-wide (340-meter-wide) near-Earth asteroid called 99942 Apophis that will cruise harmlessly by Earth, about 19,000 miles (31,000 kilometers) above the surface. That’s within the distance that some of our spacecraft that orbit Earth.