Mucus (shown in pink) is secreted by a cell in the stomach. (Credit: The Path to Digestion Is Paved with Repair. Underwood J, PLoS Biology Vol. 4/9/2006, e307. doi:10.1371/journal.pbio.0040307) We know it best as a stringy slime dripping from noses and as viscous, discolored goop hacked up by sickened airways. But it’s so much more than that. Coating the surfaces of guts, eyes, mouth, nasal cavity and ears, mucus plays a range of important physiological roles — hydrating, cleaning ...read more

(Credit: ESA/GCP/UPV/EHU Bilbao) Near the north pole of Mars, a dust storm has been ravaging for over a month. The dark clouds have been moving around the ice cap at about 4.5 mph (2 m/s), as observed by The European Space Agency’s (ESA) Mars Express spacecraft. The above image frames make up a timelapse covering about 70 minutes, as dust storms push across the planet's north polar ice cap. These storms usually last for a few days or weeks but can cover the entire planet when they&r ...read more

A sulfur-crested cockatoo, the same species as Snowball. (Credit: Martin Pelanek/Shutterstock) Whether it’s doing the twist, the moonwalk or flossing, people love to dance. Moving to music is a universal human phenomenon. But curiously, in the animal kingdom our need to bust a move is nearly unique. Not even primates – our closes evolutionary relatives – dance. Parrots are the only known exception. The vocal birds have a couple of go-to dance moves. They bob their heads ...read more

Long before this cave painting was made, our ancestors met and interacted with multiple types of ancient human. (Credit: Jannarong/Shutterstock) For the past ~40,000 years, Homo sapiens — modern humans — has been the only Homo species on Earth. But for most of our history, there were close evolutionary cousins of ours, human but not quite like us, coexisting and evolving at the same time in different regions. Some of our now-extinct relatives, such as the Neanderthals, are well ...read more

For children of the 1960s, Apollo was a not a single event but an extended way of looking at the world. Here, boys watch the Apollo 8 Christmas Eve broadcast. (Credit: Bruce Dale/National Geographic Creative) The 50th anniversary of Apollo 11--which kissed lunar soil on July 20, 1969--has prompted a flood of retrospectives. My local Barnes & Noble features an entire long table covered with anniversary books. If you want a lightly fictionalized big-screen account of Apollo 11, you can wat ...read more

Take action with the EarthEcho Water Challenge to collect and share water quality data. Then, work to protect your local water resources. About the EarthEcho Water Challenge On March 22, this year’s EarthEcho Water Challenge kicked off, empowering young people and community members around the world to monitor and protect local water resources in their communities. Initiated in 2003 as the World Water Monitoring Challenge (in celebration of the U.S. Clean Water Act), this year-round, ...read more

(Credit: Karl Gottlieb von Windisch/Wikimedia Commons. Public domain image) In 1783, an autonomous machine beat Benjamin Franklin in a game of chess. Well, at least that’s what he was led to believe.   Franklin’s opponent was a life-size, humanlike figure seated at a large wooden cabinet, supposedly rigged with machinery that made it capable of playing a game of chess without human support. It was known as the Turk. Over 230 years after the automaton played its mat ...read more

(Credit: Nopphon_1987/Shutterstock We all know smoking is bad for your health. But it seems smoking might be bad for your personality, too. A recent paper published in the Journal of Research In Personality reports that, compared to people who didn’t smoke, cigarette smokers were more likely to report not-so-great changes in certain aspects of their personalities. What’s more, giving up smoking didn’t help reverse those changes. Smoking: Through the Years The ...read more

Soy products have repeatedly been found to help cholesterol levels. But do they do enough to make a difference? (Credit: 1989studio/Shutterstock) If you pick up a carton of soy milk, chances are you’ll spot some sort of verbiage boasting the beverage’s heart health benefits. But it’s not the only soy-based food product bearing a “heart healthy” badge. That’s because, in 1999, the Food and Drug Administration (FDA), the federal agency responsible for supervi ...read more

Stromboli erupting on July 3, 2019. Image by Anil Charley/Twitter. There is the strong tendency in humans to look for patterns, even when none exist. This is amplified by the modern effect of news media, where certain events make headlines for reasons not necessarily related to the severity of the event. We see this frequently in geology, where a news-making eruption or earthquake then starts a cascade of reports of other eruptions and earthquakes that follow, even if they aren't disaste ...read more