The Earth's continents are in constant motion. On at least three occasions, they have all collided to form one giant continent. If history is a guide, the current continents will coalesce once again to form another supercontinent. And a study in Nature now shows how that could come about.
You can think of continents as giant puzzle pieces shuffling around the Earth. When they drift apart, mighty oceans form. When they come together, oceans disappear. And it's all because continents sit on moving plates of the Earth's crust.
Republican presidential candidate Mitt Romney's losses on Tuesday, while not very meaningful in the race to accumulate delegates, have raised questions once again about his ability to inspire passion from his party's base and about his viability in the general election.
Rival Rick Santorum's victories in Colorado, Missouri and Minnesota dealt a setback, if not exactly a body blow, to Romney — whom Santorum routinely dismisses as a candidate with a big machine but no core.
Ask Detroit teachers about their biggest challenge and many will say, "You can't teach kids who don't come to class." Last year, the average Detroit public high school student missed at least 28 days of school.
Now, as part of its effort to get parents more involved, the district has launched a major initiative to improve attendance. The effort includes parent workshops and attendance agents charged with pushing parents to send their kids to school every day.