The old way to think about your dog's "human age" — the age in actual years times seven — is wrong. And researchers now have a new formula they think will calculate your dog's age more accurately.

Simply put, compared with humans, dogs age very quickly at first, but then their aging slows down, a lot.

As the impeachment inquiry against President Trump continues its march through Congress, questions are churning around his secretary of state, Mike Pompeo.

Updated at 8:08 a.m. ET

Iran freed an American held prisoner for the past three years, the White House said Saturday, while Iran said the U.S. was freeing an Iranian scientist held in America in return.

"After more than three years of being held prisoner in Iran, Xiyue Wang is returning to the United States," the White House said in a statement Saturday morning. "A Princeton University graduate student, Mr. Wang had been held under the pretense of espionage since August 2016."

On a pitch-perfect autumn afternoon, a remote sheep farm in southern Greenland is quiet. The only movement is from a little girl playing outside her house with a fluffy border collie puppy.

The silence is abruptly broken when dozens of sheep come thundering across the hills overlooking the farm. Shooing them along is the girl's grandfather, Lars Nielsen, and her dad, 37-year-old Kanuk Nielsen.

Former Vice President Joe Biden is defending himself against criticism over a heated town hall earlier this week in which he called a voter a "damn liar" and challenged him to a push-up contest and IQ test. The voter, an 83-year-old retired farmer, stood up to ask about Biden's and his son Hunter's work in Ukraine, making some false accusations about it. He also said Biden was too old to run for president.

When students in wilderness EMT Alice Henshaw's training courses grab practice dummies for CPR drills, they have their choice of a traditional, flat-chested training manikin or one that looks a little different: a manikin zipped into a neoprene vest with silicone breasts.

The last time Caroline Kennedy led an aircraft carrier christening, she was 9 years old. Fifity-two years later, she'll be the one breaking the bottle against the bow of the USS John F. Kennedy as her mother Jacqueline previously did.

Ambassador Kennedy and her family will join an estimated 20,000 guests on Saturday to officially christen the new ship.

And as the famous family arrives in Newport News, Va., for the invite-only ceremony, the men and women who built the ship are marking the moment.

Dr. Marie-Roseline Bélizaire had just gathered the members of her Ebola response team for a morning meeting when they heard the rat-a-tat of gunfire.