Actor Matt Damon is convinced the Earth is on the verge of a "sixth extinction" that could even wipe out the strutting homo sapiens largely responsible for the looming calamity.

The Republican two-step on ethics reform has proven an amusing spectacle this season. First come panicked promises of reform from GOP congressional leaders; then come rank-and-file pushback and a hasty public retreat. A typical case presented itself when Speaker Dennis Hastert and House Rules Committee baron David Dreier proposed a blanket ban on all privately funded congressional travel. Mere days later, newly elected House Majority Leader John Boehner took the occasion of a February Meet the Press appearance to tell Tim Russert, “I have my doubts about that.”

Last month, the world's population quietly hit 6.5 billion. Our natural response to that statistic may be to panic. But to experts, the implications of population growth are more complex. We look at what the numbers mean for the global environment, economy, and public health.

After the recent confirmation of Supreme Court Justices John Roberts and Samuel Alito, it was only a matter of time before a state like South Dakota passed a law that banned all abortions, even in cases of rape and incest. South Dakota's governor, Mike Rounds, signed the ban on Monday. While the ban is a turning point for abortion politics at home, it mirrors what's already been happening overseas. Abortion rights advocates say it's time for Americans to start connecting the dots.

He might have hoped for 10-foot letters on the Astrovision in Times Square, flash-dancing HUMANKIND SWELLS TO 6.5 BILLION. Instead, Les U. Knight found only a gentle cascade of e-mails, a few network squawks and a blurb in the occasional newspaper and on-line blog.