In one of the world’s deepest mines, scientists have discovered some of the world’s oldest water.

In northern Canada, the Kidd Creek Mine is almost 10,000 ft deep. Here, miners search for copper, zinc, and silver ore in volcanic material that was once the floor of an ancient sea.

At the very bottom of the mine, they drilled an exploratory borehole even farther down to look for more metal ore.

What they found was possibly the oldest water in the world, trapped in the rocks for more than 2 billion years.

Why is this important? It provides a snapshot of Earth from that far distant time before there was anything but single-celled life on the planet.

And what was water like then? Very different.

The water from this ancient sea is eight times saltier than today’s ocean water. Trapped in it are helium, argon, neon, krypton, and xenon gases.

And, surprisingly, sulfur isotopes which show that ancient single-celled organisms must have lived in it long ago.

Scientists are still analyzing this ancient water, in hopes of better understanding not only our juvenile Earth, but also the types of extreme environments we may find elsewhere, like on the moons of Saturn and Jupiter, where there are vast oceans of water trapped beneath ice sheets.

If basic life forms existed in our ancient water, without sunlight or any contact with the surface, it is possible we will find them in other places, too.

Humans have been painting to memorialize their lives since the Stone Age, using techniques that endure to this day.

The earliest art supplies we’ve found—abalone shells full of ground ochre and charcoal—were in the Blombos Cave in South Africa, and are up to 100,000 years old. But we haven’t yet found paintings to go with them.

By 40,000 years ago, tribes in Europe, Australia, and Indonesia painted images of hunters and herders on cave walls, and had expanded their palette to include many colors.

Pigments for these paints included blood, sap, berry juices, dried plants and roots, and many minerals.

Iron oxide pigments were highly valued for their durability, and prehistoric mining trails around the famous Lascaux Cave in France suggest that, 25,000 years ago, painters traveled many miles for these materials.

Early artists mixed their pigments into paint using water, saliva, urine, or animal fats. They then applied them with fingers, brushes, or by blowing them through hollow bones, like today’s airbrushes.

The Egyptians continued the modern advancements, mixing paints with binding agents like egg and began painting on plaster.

Greeks and Romans expanded upon these techniques, to create a painting style not matched till the Renaissance—when Italian artists made paint with plant oils to create works of astonishing color and depth that still captivate viewers today.

Just how likely are you to be struck by lightning? And what can you do about it?

In another EarthDate, you heard how lightning is essential to life on Earth. It frees up nitrogen in the atmosphere to make it available to plants, which form the base of our food web.

For that to happen, you’d think there must be a lot of lightning. And you’d be right.

Storms around the world produce about a billion and a half lightning strikes each year—which hit about 20,000 people. Of them, only 10 percent, or 2,000, die.

That’s a lot, but it makes for pretty slim odds—about 1 in a million.

To make them even slimmer, try these simple guidelines:

First, the obvious: don’t go out in a lightning storm. Most buildings have lightning rods, wiring, or plumbing that will guide the lightning safely into the ground.

But stay out of the shower and off the landline. Plumbing and electric lines could carry a charge.

If you are caught out, avoid high places, where you’re closer to the clouds.

Also try to avoid flat open spaces, where you might be the tallest object.

And, large trees—lightning can vaporize the water inside them, causing them to explode.

If you can get to, or stay in, your car, that’s a good place to be. The frame, wheels, and dripping rainwater can carry the charge to the ground, leaving you insulated.

Just a few years ago, Venice, Italy, would flood more than 60 times a year. Until the Venetians decided to push back.

All that water was due to where Venice is built—in the middle of a lagoon. And why was it built there?

In the fifth century, Roman farmers, fleeing invaders, moved out to fishing huts on a string of low mud islands. Battered by tides, they built houses on stilts.

But their protection worked. While barbarians pillaged Italy, Venice thrived. Their settlement grew into a city, which grew into the greatest naval power in the Mediterranean—with the whole thing built on stilts.

Over the centuries, sediments beneath the city gradually compacted. The Venetians responded by jacking up their buildings farther.

But in the twentieth century, drilling and extraction of groundwater and natural gas caused the city to sink faster, while the Adriatic Sea level rose.

Tidal flooding became so frequent that Venice built a system of 79 enormous steel gates at the inlets to their lagoon. Each gate is 100 ft tall and weighs 300 tons. It rests flat on the seafloor—till an overly high tide is predicted.

Then, Venice pumps the gates full of air, and they slowly stand up, able to hold back 10 ft of ocean surge. When the threat is over, they sink back to the seafloor.

There are many other subsiding cities, like New Orleans, Miami, and Jakarta, keeping a watchful eye on the sea—and on the amazing gates of Venice.

Strange weather around the world is often blamed on El Niño. Who is this “boy,” and how does he cause so much trouble?

El Niño is simply warmer-than-normal water in the Pacific, off South America. It was first noticed by sailors in the 1600s, who named it after the Christ Child since it came in December.

We now know that El Niño lasts several months to several years, returns every 2 to 7 years, and is caused by atmospheric pressure.

In a normal year, high pressure over the Pacific and low pressure over Australia and Indonesia form trade winds. These blow west across the Pacific, pushing warm surface water with them—which brings humidity and rain to Australia.

Meanwhile, cold water from the deep replaces the exiting warm water, replenishing nutrients and fish stocks along South America.

But in an El Niño year, the high- and low-pressure areas are reversed, and trade winds stop.

Warm water stays put. Australia and Indonesia get less rain. South America gets it instead.

The shifting temperature patterns alter the jet stream, which changes the tracks of seasonal rains.

This makes it warmer and drier in the northern U.S. and Canada. Colder and wetter in the southern U.S. And causes droughts as far away as India.

La Niña is a natural compensation—colder-than-normal water in the western Pacific—which sometimes follows El Niño and brings opposite weather effects.

In the 1970’s, the Viking rover landed on Mars and detected no life.

In 2003, NASA took the same technology to the Atacama Desert in Chile and got the same reading. Was there really no life there?

And by extension, no life on Mars?

You might think that the driest place on Earth is the Sahara. But they’re actually polar deserts, like the McMurdo Dry Valleys of Antarctica, and high deserts, like the Atacama. There are places there where it hasn’t rained in 500 years—if ever.

Surprisingly, the driest deserts are cold, not hot. That’s because cold air holds 20 times less water vapor than hot air.

Though average temperatures in McMurdo are below freezing, the Atacama averages 70 degrees—but it’s in the rain shadow of both the Andes and the Chilean Coastal Range. It’s at 8,000 ft, where the air is very thin. And it’s near the equator, where solar radiation is extreme all year long.

This is the most similar environment on Earth to Mars, which is why NASA is testing old and new Martian exploration technology here.

While the Viking equipment missed any signs of life in the Atacama, new understanding of extremophiles—life found in extreme conditions—led NASA scientists to look beneath the soil and within rocks, where they found photosynthetic bacteria.

And if life can exist here, in the most inhospitable place on Earth, we might also find it on the next mission to Mars.

In school, we learned the continents: the Americas, Eurasia, Africa, Australia, and Antarctica—with island nations like New Zealand floating off by themselves.

So you may be surprised to hear that scientists have discovered a new continent—and New Zealand is part of it, after all. In fact, it’s one of the only parts of what’s now called Zealandia that’s above sea level.

Most of Zealandia, which is almost two-thirds as big as the continental United States, is more than a kilometer underwater.

That’s deep enough that you might be thinking, “That doesn’t sound like a continent.” Except the seafloor around it is 4 kilometers deep.

Antarctica, too, if you melted all the ice, would be just a few islands, with most of the western part of the continent submerged.

Which begs the question: what exactly makes a continent? The leading factors are its mineral content and density.

The seafloor is dense and heavy with iron, so it rides low in the mantle that supports all of Earth’s crust.

Continental crust is high in silica and aluminum. It’s less dense and much thicker than oceanic crust, so it floats higher in the mantle, like ice on a lake.

Most continents are large landmasses surrounded by a shallow ocean shelf.

But Zealandia is a small landmass surrounded by a large ocean shelf, having been pushed around, squeezed, then sunk by plate tectonic forces over millions of years.

California’s Central Valley is an agricultural bonanza, producing a third of America’s food crops. But it’s facing serious water challenges.

The valley floor is 20,000 sq miles of some of the most fertile soil on Earth. Here, the sun shines 300 days a year. More than 250 different crops grow, worth $17 billion per year.

The valley was developed into farmland around the turn of the twentieth century. When farmers arrived, they began to drill wells into the fresh-water aquifers below.

By the 1930s, scientists began to notice an impact. Some of the aquifers, with their water levels and pressure drawn down, compacted. This meant they would never refill to earlier levels, and the land above them subsided.

This continued into the 1970s, when sinking land, up to 30 ft in parts of the valley, had damaged roads, bridges, and buildings so dramatically that California spent millions to repair them and built canals to bring in water.

The problem was alleviated—until conservation elsewhere in the state reduced water in the canals and valley farmers pulled hard on their wells again.

The wells remained unregulated until 2012, when California passed serious water legislation. It will be decades before it’s fully phased in, but the hardest-hit areas are being addressed now.

In the meantime, the valley floor and the water table continue to fall.

Grains of pollen are like Mother Nature’s fingerprints, allowing scientists to track the migratory paths of dinosaurs and solve long-cold murder cases.

Flowering plants evolved 100 million years ago, and within 30 million years dominated the planet. Today, there are almost 400,000 species.

One reason for their global success is their remarkable fertilization system.

A single flower can produce hundreds of thousands of pollen grains, which can be distributed by the wind, insects, or animals, fertilizing other plants miles away.

Each plant produces a distinct-looking pollen grain. And each place on Earth, even each square block or backyard garden, has a distinct mix of plants.

By studying the mix of pollen grains found on a person, animal, or object, scientists can now tell precisely where they have been.

And since pollen is highly durable, outlasting the plants that produced it by thousands of years and surviving in the fossil record for millions, scientists can use it for ancient detective work.

Recently, paleontologists used fossil pollen in the digestive tracts of dinosaurs to tell what they ate and where.

Forensic palynologists now use pollen found on murder victims and suspects to place them in the same location, or even to discover where bodies have been hidden.

The new science of palynology is cross-pollinating many other fields, allowing a deeper understanding of Earth.

Since 2000, the Arctic has warmed more than other areas, up to 5°F. And that’s beginning to melt the permafrost.

In the Arctic winter, the earth is frozen, from tens to thousands of feet down.

In summer, the top several feet melt, creating a so-called active layer where plants can take root.

Below that is permafrost: frozen soil that contains a great deal of ice. For these regions, it’s like bedrock—stabilizing the active layer and providing a solid footing for buildings.

But as the melting reaches deeper into the ground, the permafrost is not so permanent and is becoming unstable. Roads in Alaska and Canada are beginning to undulate and ripple, and runways are at risk. Foundations are shifting, making some buildings and houses unusable. Surface water drains and floods unpredictably.

What widespread effects could this have?

Permafrost, like regular soil, contains organic material from dead plants and animals.

As it melts, the organic matter decays, releasing CO2 and methane, both greenhouse gases. This could create a feedback loop of continued greenhouse gas release and further warming.

But melting permafrost is also creating a deeper soil layer, which may allow forests to replace tundra. In other places, it’s toppling existing forests and replacing them with wetlands. These would absorb CO2.

With permafrost covering nearly a quarter of the Northern Hemisphere, scientists are keeping a close eye on these changes and how they impact climate models.