As of 2025, humans have only dug 0.2% the way to Earth's center

The deepest human-made hole on Earth is in Russia’s Arctic North

Driven by Cold War competition, the Kola Superdeep borehole was a project in the 1970s to uncover the composition of the Earth by boring underground. The mission managed to go 7.6 miles into Earth’s crust, the deepest human-made hole on Earth.

How we know what’s deep inside the Earth, despite never traveling there

We'll likely never see the Earth's core, but we can make educated guesses about what it's like down there. Nearly as hot as the sun's surface and under impossibly high pressure, the inner Earths extreme conditions make it impossible to explore. Yet, seismic waves during earthquakes, volcanic eruptions, and light waves from the sun provide fascinating insights about our planet’s mantle, crust, and core.

NASA explores Earth's deepest oceans to prepare for space

By studying extreme environments in Earth's hadal zone—the deepest part of the ocean —NASA tests technologies, probes life under crushing pressure, and gathers clues about potential oceans and possible life on worlds like Europa and Enceladus.

Travel through deep time with this interactive Earth

Explore key moments in Earth’s transformative history as continents drift and climate fluctuates over 4.6 billion years. The Smithsonian presents a series of interactive snapshots of the earth. From its toddler years during the Hadean period, when its surface was mostly molten, to the mostly unidentifiable landmasses of the future earth, 100 million years from now.

Learn how aquifers and wells provide the largest reserves of accessible freshwater on Earth

Roughly a third of Earth's freshwater is stored underground in aquifers—permeable and porous rock formations where water naturally flows from the Earth's surface and accumulates. About half of this groundwater is accessed through wells, a feat of engineering used for thousands of years.

Lining up every microbe on Earth would stretch to about 105,000 light-years

There are about 10²⁷ such organisms on the planet, many of which are adapted to produce energy through uncommon reactions in unconventional environments, such as within rocks or near volcanoes on the ocean floor. Studies of these organisms have reframed astrobiologists' search for life beyond Earth by broadening the parameters under which life can exist.

Explore the animals that populate the depths of the ocean, from fish and coral in the first few hundred feet, all the way down to the bottom of the Mariana Trench.

In 2025, UK scientists began studying climate data from a 1.5-million-year-old ice core

The Antarctica sample will be melted and analyzed in Cambridge to learn about prehistoric environmental conditions. Researchers hope the ice core reveals how Earth's glacial cycles shifted dramatically around 800,000 years ago.

How humans are engineering the planet

One fact about our time is becoming increasingly well-known. No matter how far you travel, no matter in which direction you point, there is nowhere on Earth that remains free from the traces of human activity.

Scientists can determine Earth's past climate conditions by analyzing air trapped in microscopic bubbles within ice cores—columns of compressed snow layers that build up over hundreds of thousands of years.

Records of Earth's magnetic field on the seafloor validated plate tectonics

Matching glacial, fossil, and rock records, mountain ranges, and continental shapes across oceans was insufficient evidence for continental drift. Precise measurements of magnetic minerals on the ocean floor revealed seafloor spreading, which could only be explained by moving landmasses.

How scientists study Earth's geocorona, the farthest portion of the planet's exosphere

Seen via ultraviolet radiation scattered by neutral hydrogen in the region, observations by the ESA/NASA Solar and Heliospheric Observatory indicate that the geocorona extends roughly 50 times Earth's diameter above its surface. At this distance, the geocorona extends beyond the Moon's orbit.

The inhabitability of the Martian environment presents significant colonization risks

Terraforming the thin atmosphere, toxic dust, extreme cold, and lack of magnetic field is infeasible, given limitations to the size of what can be sent to Mars. NASA and SpaceX are instead exploring creating underground shelters.

Why Earth will be made uninhabitable by the sun far sooner than when the sun dies

The star has enough fuel to continue fusing hydrogen into helium for another 5 billion years, but the gradual increase in core temperature from these reactions will brighten the sun by 10% every billion years. Some models predict that the increased radiation will be enough to vaporize all of Earth's surface water about 1 billion years from now, long before the sun becomes a red giant and disintegrates the planet.

Geological tremors on the moon provide evidence that it is shrinking

Apollo seismometers have collected moonquake data, which scientists have analyzed to map the moon's interior and reveal that fault slips producing tremors are the result of sublunar cooling and contraction. It also revealed that the moon's inner core is about 500 kilometers (311 miles) across.

There are likely millions of small black holes lurking undetected near us in space

Because black holes are so hard to spot directly, astronomers rely on models of galaxy and star evolution to estimate their population. A recent study used simulations and galactic data to show that about 1% of all matter in the universe is locked inside black holes.

The missing continent that took 375 years to find

It took scientists 375 years to discover the eighth continent of the world, which had been hiding in plain sight all along. But mysteries still remain.

A look at the Kidd Creek Mine in Canada, which houses the world's oldest isolated water

The mine sits on the Precambrian Canadian Shield—an ocean floor dating back 2.7 billion years. Exhibiting a musty smell, the water is 10 times saltier than seawater and offers insights into Earth's ancient seabed.

The simplicity of immersed tube tunnels

Tunnels have traditionally bored holes through the earth below the water. On the other hand, immersed tube tunnels connect hollow, massive sections in trenches along the floor of the body of water. Each section is built on land, floated to the site, submerged, and connected. This method saves money by reducing expensive underground work, and it preserves an area's aesthetic appearance.

Track the location of the Voyager probes, currently between 13 and 15 billion miles away from Earth.

Explore next-generation geothermal projects worldwide

This tool from the Clean Air Task Force allows users to see the location of geothermal power systems to depths of 12.5 kilometers (7.8 miles), where temperatures reach about 450 degrees Celsius (842 degrees Fahrenheit), including proposed, abandoned, and in-development projects.

The massive sinkholes of China

Parts of China's limestone-rich terrain is fertile ground for massive caves, where some of the world's largest sinkholes are located. Hidden away in dense, lush forests, geologists are frequently discovering new sinkholes to explore. This piece...

The most advanced 'bunker-buster' bomb can penetrate 200 feet below soil or concrete

The GBU-57 Massive Ordnance Penetrator is delivered exclusively by the B-2 Spirit stealth bomber, which carries only two at a time. Using GPS-guided fins and a steel alloy casing, it burrows 200 feet underground before detonating.

Biosphere 2 is the largest Earth science experiment ever built

The vivarium—an enclosed system including animals and plants—is sealed from below with 454 metric tons of stainless steel liner and includes an ocean habitat with more than 700,000 gallons of seawater. B2 is visited by 100,000 people yearly, including more than 10,000 K-12 students.

Where you are located in a gravitational field affects how quickly you age

The closer something is to the center of a massive object, the greater the strength of the massive object's gravitational field as a result of space-time being depressed more severely. Time passes more slowly the deeper an object is in this gravitational depression, meaning objects in the universe naturally seek to age more slowly.

Universal limit to technological development may prevent finding alien civilizations

Given the vastness of the Universe, detecting alien life may require technological progress beyond the limits of what is sociologically viable and physically possible. Although interstellar civilizations are unlikely, messaging techniques and probes may improve the odds of successful communication with other intelligent life.

About 20% of asteroids are metal worlds similar to Earth's core

The biggest of these (that we know of) is 16 Psyche. Measuring 140 miles across, its iron and nickel content is potentially worth 10,000 quadrillion dollars. NASA’s mission to Psyche—reaching the asteroid in 2029—will study it to learn about its formation.

As of 2022, scientists estimate that 117 billion people have been born on Earth

Although no demographic data exist for more than 99% of the time humans have existed, this value can be estimated by tracking approximate population sizes over different periods and the birth rates within those periods. In 2022, about 6.8% of humans that have ever been born were alive.

In 1963, a basement renovation in Turkey revealed a passageway to a hidden, multilevel underground city that once housed as many as 20,000 people

According to the physics of black holes, our 4D reality may be a hologram—a projection of information coded on a 2D surface on the edge of the universe.

After NASA's Voyager 1 captured Earth as a single pixel as it left the solar system in 1990, astronomer Carl Sagan used the image to reflect on humanity's fragility and the responsibility to protect 'the only world we've ever known.'

Most of the observable universe's volume consists of voids and supervoids—enormous regions of space with little to no galaxies, stars, or light.

Volcanoes 'die' when their supply of magma runs out, if they are shifted away from their underlying magma reservoir, or if they get clogged by collapsing or their magma cooling back into rock.

While the sun's gravity keeps the planets in orbit, their gravity also pulls on the sun, causing it and everything else in the solar system to orbit around a mutual balance point called the barycenter—the true center of the solar system.

Explore the archaeological treasures of Pompeii, the city buried under volcanic ash when Mount Vesuvius erupted in 79 CE.

Massive 3D printers have been used to build homes by stacking layers of 'concrete toothpaste,' a fire-resistant material that effectively insulates against outside noise.

Apollo astronauts left items in the moon's 'toss zone,' including golf balls, family photos, and bags of human waste, to make room for lunar rocks.

Visualize the path of every solar eclipse from 1900 to 2099 and see what each looks like when observed from different locations on Earth.

The boiling temperature of water decreases with increasing elevation because the molecules need less energy to overcome the lower atmospheric pressure associated with thinner air.

SpaceX's S-1 or 'prospectus' revealed many previously unknown details about the company, including its unprofitability despite doing $18.7B in revenue in 2025, exactly how many voting shares Elon Musk will have in the company (roughly 85%), and more.

How fusion—which releases energy when two lighter atoms combine to form a heavier atom—differs from fission

The American Society of Civil Engineers' infrastructure report card gave the US a C in 2025, its highest grade since the project launched in 1998.

As of 2025, the most cited papers in science include a review of graphene, methods to improve image recognition, streamlining electron density calculations, and optimizing protein studies.

In 1984, Operation Smash Hit intentionally crashed a 239-ton train into a nuclear waste canister at 100 miles per hour to prove the canister's safety, which remained completely intact and lost just 0.29 of its 100 pounds of pressure.

Budweiser stores yeast derived from the original 1800s strain in a secret bunker, which only the Head of Yeast Management can access—not even the CEO

Bone marrow (soft tissue found inside certain bones) generates roughly 500 billion new blood cells each day

Take a 3D tour of the Hajj, Islam's annual pilgrimage to Mecca, undertaken by more than 1.5 million Muslims each year.

Alzheimer's can lead to brain shrinkage, with an average of around 2% of volume reduction per year

Indefinite cloning of some endangered species may not sustain their longevity because cloning success rates decrease as genetic mutations accumulate.

Scientists have struggled to pin down Ebola's natural reservoir species for decades, but the available evidence suggests that it's very likely fruit and insect-eating bats found in Africa.