About 5 percent of all UFO sightings cannot be easily explained by weather or human technology. A physicist argues that there's compelling evidence to justify serious scientific study and that the skeptics should step aside – for the sake of humanity.

"We won’t have a ‘yes’ or ‘no’ answer to finding life elsewhere. What we will have is a high level of confidence that a planet appears alive for reasons that can only be explained by the presence of life."

65 million years ago, a monster asteroid wiped out 2/3 of all life on Earth, including the dinosaurs. But an astrophysicist explains why it’s the smaller near-Earth objects (NEOs) that pose a greater imminent threat.

Now that it’s summer in the Northern Hemisphere, our thoughts turn to … mosquitoes! Here’s some handy info from a biologist.

As atmospheric carbon dioxide levels rise, rice plants - the primary food source for more than 3 billion people - produce fewer vitamins and other key nutrients. 

Mars' massive dust storms have been challenging - and enticing - scientists for decades. From NASA, here’s the scoop on Martian dust.

A bit of amber preserved a drama from 100 million years ago, an interaction between a tick and a spider.

It's getting harder for wild animals to find human-free spaces on Earth. New research suggests that human disturbance is creating a more nocturnal natural world.

Kilauea volcano's Fissure 8 has produced a large, channelized lava flow that's acted like a river, eating through the landscape, finally producing clouds of steamy, hazardous "laze" as hot lava meets the cold ocean.

Since the 1970s, scientists have treated pulsars and magnetars as 2 distinct populations of objects. Now they think they might be stages in a single object's evolution. A new NASA ScienceCast has more.