He was the first American to orbit Earth, and he holds the record for being the oldest person to travel in space.
The pill that prevents the contraction of HIV comes with plenty of barriers. Meet two people knocking them down in Chicago.
The city saw an intense spike in air pollution.
Paleontologists have discovered more dinosaur feathers preserved in amber — the fluffy plumage might have been common.
The numbers have researchers very concerned about Americans' health and well-being.
Their numbers have dropped 40 percent in the last 30 years.
NASA's Cassini spacecraft is exploring Saturn and capturing new images, but its time grows short as it runs out of fuel.
The nation's top doctor is sounding the alarm on e-cigarettes, especially when used by teens and young adults.
He's called EPA regulations "coercion" and has fought to slow down the move away from fossil fuels.
Compared to much of the world, the U.S. has tried to tackle the problem head-on.
Researchers predict nearly a third of the global polar bear population could die out in as little as the next 35 years.
The request came a day after the U.S. Army Corps of Engineers said it would look into alternative pipeline routes.