Probable asteroid (Apophis) impact
After its discovery in 2004, astronomers gave the asteroid Apophis a 2.4 percent chance of hitting the earth during its close flyby on April 13, 2029. If the 1,066-foot (325 meters) asteroid were to strike our planet, the blast could equal hundreds of megatons.
Fortunately, further analysis showed that Apophis will miss the Earth by 19,400 miles (31,300 kilometers) in 2029. Extrapolating further into the future, another approach in 2036 is an even bigger miss. Apophis has only a one in a million chance of hitting Earth on that pass.
Originally given a 1 in 37 chance to hit Earth, the near Earth object Apophis caused a bit of a panic in late 2004 with a high probability to hit Earth in 2029 or 2036. But what would happen if such a massive object collided with mother Earth? Don't even bother comparing it to a nuclear bomb because it's way beyond that.