From my experience working with odors, I knew that it is very unusual to find two mixtures of odors that cannot be discriminated. And because the number of possible mixtures is astronomically high, it always seemed to me that 10,000 was much too small a number

A man walks through an underground tunnel network in London in this National Geographic Photo of the Day from our Your Shot community.

“Biologists need to know how fast the snakes might spread and what corridors they are likely to use,” Pittman said, “so that conservationists can prevent population expansion.”

Vibrant spring blooms in the northern hemisphere and dazzling autumn displays in the southern make this the perfect season to get outside and explore.

The Big Bang radiation discovery happened there-and when you look at Antarctic conditions, you can understand why.

Jason uses archaeology to tell migrants’ stories along the US and Mexico border. Where many might see bottles and backpacks as trash along the side of the road, Jason sees them as artifacts of individuals’ lives.

Animal activists believe some sanctuaries undermine the very mission they're meant to serve.

Young Galápagos sharks swim in this National Geographic Photo of the Day by Thomas Peschak.

The largest of the detected floating objects is almost 79 feet (24 meters) long; the other piece is 16 feet (5 meters) long, according to Australia's Prime Minister Tony Abbott, who announced the details. If the pieces belong to the missing jet, their large size suggests that the plane hit the water...

"I came across this friendly female dugong whilst snorkeling on the Ningaloo Reef in Western Australia," says Your Shot community member Janine Marx.

Live From Space: Explore the world's interests from 267 miles up. Follow the path of the International Space Station in real-time as it travels around the Earth, and see the ISS astronauts' unique perspective of a world without borders.

A man rows up to a market on a lake in Kashmir in this National Geographic Photo of the Day from our Your Shot community.

Days and nights of equal length always fall before the spring equinox and after the autumnal, or fall, equinox.

Beginning at 2:07 a.m. EDT, the 45-mile-wide (72-kilometer-wide) asteroid named 163 Erigone will slip in front of the bright star Regulus, located in the constellation Leo, the Lion, causing the star to become invisible for up to 14 seconds.

Infrared film changes the colors of an Arctic landscape in this National Geographic Photo of the Day.

"It's a time when people let go of their inhibitions," says Suhag Shukla, executive director at the Hindu American Foundation. "It's a playful celebration, and the colors remind us that beneath the surface we're all the same."

The National Geographic Society, one of the only nongovernmental map policy bodies in the world, said Wednesday it had made no formal decision on Crimea, despite erroneous reports claiming it had remade its maps to depict Crimea as part of Russia.

The multiverse may even help explain one of the more vexing paradoxes about our world, sometimes called the "anthropic" principle: the fact that we are here to observe it.

You have to live in the next three seconds and make decisions about what’s going to happen next: What direction is the action moving? What will the light be like?

Turtles have evolved to synchronize their nesting with times of year when the incubation temperature produces roughly equal numbers of male and female hatchlings. If that ratio goes out of whack, populations could plummet, owing to a scarcity of one or the other of the sexes.

A Kazakh herder drives sheep during a spring blizzard in this National Geographic Photo of the Day from our Your Shot community.

New analysis of MESSENGER spacecraft images of Mercury show the planet has shrunk almost nine miles in diameter.

The Arctic whale's tusk is actually a tooth that can grow more than nine feet long; it has baffled people for centuries.

Not only is marijuana a "gateway" into other addictive drugs, but it also "impacts the next generation more than we thought," says neuroscientist and author of a new study Yasmin Hurd.

If you eat the food you've dropped, you're also eating any bacteria the food picked up. Both studies set out to determine how long it takes for bacteria on the floor to stick to food.

Watch a live video conversation with astronaut Piers Sellers and other explorers on Thursday, March 20 at 2:30 p.m. EST. http://bit.ly/OyEil5

Antennas form part of the ALMA telescope in Chile's Atacama Desert in this National Geographic Photo of the Day from Dave Yoder.

Using biological light projectors called photophores, fish, squid, and smaller creatures hunt prey, summon mates, and cast defensive illusions.

By Tuesday night, the moon will have slid lower between the cosmic duo, creating a stunning conjunction. Luna will be especially close to the 263 light-year-distant Spica, which is the lead star in the constellation Virgo.

The observations strongly support the cosmological theory of "inflation," which explains how the early universe smoothly expanded to unimaginable vastness in the first fractional second of its existence.

the real St. Patrick wasn't even Irish. He was born in Britain around A.D. 390 to an aristocratic Christian family that owned a townhouse, a country villa, and slaves.

Roe deer are captured in this National Geographic Photo of the Day from our Your Shot community.

"The overall percentage of Americans opposed [to medical testing with animals] is 40 percent, the same as it was five or six years ago."

See the ten most popular travel pictures from February.