We may not think of it every day, but Earth is a sitting duck in space. The planet that we call home has been enduring impacts of space debris for countless eons, the only reason that your back yard doesn’t look like the surface of the moon is that we have this nifty thing called ‘weather‘ to fill in the holes so to speak. Generally the planet does a good job at spackling over the odd scrape and bruise it picks up once in a while however, not everything thing has been patched up just yet. Scientists have found to date not less than 170 impact sites dating as far back as 2.5 billion years ago. Many of these craters has assumed role of lakes or bays or the odd depression in the country side, and for the most part, don’t stand out. There are a few that do. A prime example is Barringer Crater in northern Arizona. That has been preserved by the arid conditions of the area. With so many impact sites around the world, and more being discovered as mankind’s advances in Earth imagery, it’s no wonder that scientists are warning that ‘the big one‘ could hit us in the near (geologically speaking) future.