Wednesday night (depending on your time zone), the Earth had a close encounter with the asteroid called Apophis. The Bad Astronomer, Phil Plait, has the details over at Slate. The asteroid was discovered in 2004, and there was a serious concern that it could hit the Earth in 2036. Since Apophis was initially estimated to be 270 meters across, such an impact would be catastrophic. It would have generated an impact roughly 20 times stronger than the largest nuclear weapon ever detonated on the planet.
Thankfully, calculations made during this recent pass have determined that this asteroid will come very close in 2029, but miss us in 2036. This is extra good news, since we have determined that Apophis is roughly 75 percent more massive than initially thought.
But there are other asteroids and near-Earth objects out there. While there are efforts to build asteroid-monitoring missions, we are still struggling with being able to find and track all of the potential impact objects. Getting rid of them or nudging them out of the way is a challenge, but as Phil Plait describes in a TED talk, not impossible.
However, with low probability events that have high consequences (like asteroid impacts), it’s really easy to put off committing resources to these efforts. Tsunami monitoring is another such example. When centers created in areas hit by these disasters have problems sustaining a budget, you know getting money to mitigate a disaster that hasn’t happened yet is not an easy feat.