According to Neil DeGrasse Tyson, the next time the Earth will even be buzzed by an asteroid is April 13, 2029, a Friday the 13th. That’s when Apophis, a near-Earth asteroid, will fly by. The asteroid is named for an evil Egyptian god, even though scientists have already determined there’s approx. zero chance it will hit our planet. Still, Tyson says it will be the largest closest thing that we have observed to come by the earth.
The orbit for this asteroid is uncertain enough that we can’t exactly tell where the trajectory will be. There is a 600miles range zone scientists called a ‘keyhole’. If the asteroid passes through this keyhole, it will hit the earth 7yrs later on April 13, 2036 (a Thursday this time). One calculation has it hitting us just off the coast of Southern California. If that were to happen, the asteroid would dive deep into the Pacific Ocean, triggering a series of tsunamis up to 50ft high. Water would only make it about a quarter mile inland along the West Coast of USA, and seeing as this is 22 years from now, we’d have plenty of time to prepare.
The problem with calculating the impact probability to earth is because of the absence of knowledge of the complete dynamics. It can't be known for certain if it will impact until, during or after the 2029 encounter, even if a spacecraft is accompanying Apophis and providing position measurements good to 2 meters. That is, the keyhole could be determined only retrospectively, after passage through it.
While we can’t completely rule out the event, Tyson says the odds are right at one in a million of Apophis hitting (that’s an actually calculated one in a million, not a figure of speech). If the forecasts are true it will come within 18,300 miles of Earth’s surface and will be visible from most of Europe, Africa and Asia. Even though it is incredibly close, there is nothing to support the theory that this will bring about an Armageddon like the one that wiped out the dinosaurs millions of years ago.