LOS ANGELES - Among the zillions of decisions that moms and dads make about how to parent, it might seem that determining the appropriate amount of time young children can spend watching TV and playing on tablets and smartphones might be a big one.
It's 1.7 miles long. Its surface is covered in a sticky black substance similar to the gunk at the bottom of a barbecue. If it impacted Earth it would probably result in global extinction. Good thing it's just making a flyby.