As calls to end fluoride in water get louder, changes to the dental health of children in Calgary, Canada, and Juneau, Alaska, may provide a cautionary tale.

Scientists aboard a research vessel near Los Angeles collected ash, air and water samples as fire blazed on the hills before them in January.

Easy replication in cattle mammary glands means H5N1 bird flu is under no evolutionary pressure to adapt to spread easily in humans.

An overlooked Antarctic water system could raise sea levels by more than 2 meters by 2300, computer simulations show.

A weathered sign in the Minnesota River Valley proudly proclaims: “World’s Oldest Rock.” Erected in 1975, it marks a 3.8-billion-year-old gneiss — or so scientists thought.

Across much of the world, loneliness increases from middle age to later years. That trend is reversed in the United States, a new study shows.

Societal upheaval can trigger uncertainty, which makes people susceptible to cognitive traps. Experts suggest some simple tools can help.

Hubble is still going strong 35 years after it was launched into space. Celebrate its anniversary with some out-of-this-world images.

While solitary black holes should be common, they are hard to find. The one in Sagittarius revealed itself when it passed in front of a dim background star, magnifying the star’s light and slowly ...

Warming temperatures can ramp up the activity of methane-producing bacteria in wetland soils, adding to methane emissions.

Rising global temperatures are driving the sharp decline in terrestrial water storage. This trend isn’t likely to change, scientists say.

Autism rates are higher than ever before, probably because of more expansive and sensitive diagnoses. Those numbers highlight the need for more support for people with autism.