On Friday 13th, 2029, the asteroid 99942 Apophis will pass as close as 15,000 km to the earth. It may pass even closer on Sunday April 13, 2036. However, the 2036 pass can't be accurately predicted until closer to 2029. During that pass, the path of the asteroid will be strongly deflected as shown in the diagram below. Nevertheless, scientists are pretty sure we are safe. The current odds of an impact are 1 in 45,000. But its still going to be close. Well within the orbit of communications satellites.
The asteroid is 350 meters in length. An impact would be locally devastating, but not an extinction event. Local, in this context, depends on where it lands. A few hundred km if it hit land, but a lot more if it landed at sea due to tsunamis. The good news is that there would be plenty of time to evacuate. In any case, its worth noting because of how close the asteroid will pass, rather than threat level. This is a game of numbers, and the scientists are good at that.
Image: Marco Polo - Wikimedia
Fortunately, there are several organizations dedicated to tracking possible asteroid strikes. The best known is B612, which produced the handy map below. It shows where, if the asteroid were to strike in 2036, the impact might occur. NASA is tracking it as well. There is also a handy countdown page here. I'm just glad somebody is paying attention.
