FDA proposes new fluoride standard for bottled water

The US Food and Drug Administration is proposing a lower concentration level standard for fluoride in bottled water, yet some scientists and environmental groups believe that the proposed limit is still too high and poses a danger to human health.

Photos reveal the recent rivers that ran across Mars

Mars may seem inhospitably dry now, but NASA's rovers have shown that water was once abundant on the Red Planet. Photos gathered during NASA's missions orbiting Mars have revealed that the planet was once home to raging rivers -- and that those rivers existed more recently than previously thought, according to a new study.