According to some calendars, May 21st, 2011, is the Rapture–the day when faithful Christians will ascend to heaven while the rest of the earth’s inhabitants will be left behind to endure the end of times.

With Social Explorer, believers and nonbelievers can learn about who might be saved by using the infoGROUP’s American Church List data–the most comprehensive religious membership survey of its kind.  This survey data enables you to estimate how many Americans might disappear on Saturday.

For this example, we looked at the US and Alameda, California, the home of Family Radio leader and Judgement Day proponent Harold Camping.  With an estimated 25.9% of the population belonging to any kind of congregation, Alameda is more secular than the rest of the US where an estimated 35.6% of residents belong.  Looking at the breakdown of major religious traditions, Judgment Day followers can speculate about how many of their fellow Americans will be saved.

You can dig deeper by comparing religious congregation membership and attendance numbers, or parse hundreds of congregation types from Advent Christian Church to Yoga Institutes.

For those of you still around after Saturday, stay tuned for more new data, tools and blog posts from Social Explorer.