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

Why the existence of extremophiles greatly improves the odds of life beyond Earth

The conditions for life have long been thought to include liquid water, an energy source, and the essential elements for organic molecules within environments on or near Earth's surface. However, because extremophiles thrive in far more inhospitable environments, astronomers now analyze exoplanets whose characteristics indicate environments that fall within a broader range of possibilities when searching for signs of extraterrestrial life.

The 45 planets astronomers think are most likely to host alien life

The list includes familiar names like Proxima Centauri b (4 light-years away) and four planets in the TRAPPIST-1 system (about 40 light-years away), but even the nearest of those would take humanity roughly 114,000 years to reach at current spacecraft speeds. The list's real near-term value is as a targeting guide for the James Webb and upcoming Nancy Grace Roman space telescopes.

There may be as many as 300 million potentially habitable planets in our galaxy

The estimate comes from a study using data from the Kepler space telescope—a project aimed at finding exoplanets—and considers exoplanets similar in size to Earth around sun-like stars. These have a greater potential to possess liquid water.

View a sample of the bioluminescent tree of life

This diagram shows 42 different light-producing organisms, from bacteria and fungi to worms, fish, and crustaceans. It illustrates how the ability to produce light has appeared multiple times across the tree of life, rather than stemming from a single ancestor.

Panspermia, the theory that cellular life came from a different planet

One of the most profound mysteries of human life on earth is the presence of living cells: organic, self-organizing, reproducing creatures with a drive to survive within given set conditions. Traditional theories posit life came from divine...

View a breakdown of the identified species on Earth

Over 2 million species have been documented by scientists, but there may be as many as a billion distinct species. The vast majority of the species on Earth are insects, while mammals form the smallest group.

Genetic analysis indicates that every organism on Earth evolved from a single cell

LUCA—the last universal common ancestor—lived about 4.2 billion years ago and likely obtained energy through the conversion of carbon dioxide and hydrogen gas consumed from atmospheric gases at the ocean's surface or hydrothermal vents—openings on the seafloor where fluid warmed and enriched with minerals by Earth's interior is expelled.

There are between 10 and 100 trillion bacteria in the gut

The composition of our microbiome is essential to overall health. Anything that disrupts the balance of the trillions of bacteria may be harmful—even treatments meant to fight infection, like antibiotics.

Depending on environment, aliens' bodies would have wide-ranging possibilities

Humans tend to imagine aliens as humanlike, but that's probably unlikely. From small space spiders to metallic carnivores, life on other planets—and how we could interact with it—is difficult to imagine.

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

The Kola Superdeep Borehole revealed two billion-year-old fossils and underground water, but the immense temperature and pressure prevented further tunneling. Beyond those depths, scientists know of Earth's interior by analyzing how seismic waves move.

The 300-million-year period where Earth looked like a snowball

Life has existed on Earth for at least 3 billion years, but the planet has not always looked like it does today. Rather than the blues and greens of our modern globe, for a 300 million-year period, the Earth was covered in ice and snow, from the poles to the equator. Surprisingly, life was thriving at the time.

How microbes limited the damage and helped clean up the Deepwater Horizon oil spill

A bloom estimated to contain about 100 sextillion microbial cells broke down much of the 4.1 million barrels of spilled crude oil into nontoxic compounds in what was one of the most significant bioremediations of a human-made disaster. The microbes involved acted similarly to the first patented genetically modified organism in US history: an oil-eating bacterium engineered in 1971.

Search for psychrotolerant and psychrophilic microorganisms found in Antarctica

Developed following a five-week expedition to the southern continent, "Life Under the Ice" allows users to examine a petri-dish-like microscopic world and uncover recordings of organisms that can withstand, or even thrive, in the harsh environment.

See how each of the more than two million known species relates to each other—and to common ancestors—in this zoomable tree of life.

The secret lives of cells

Cutting-edge microscopy has revealed previously unseen interactions of biological molecules within their cellular environment, enabling scientists to observe and analyze the molecules in a holistic view. This podcast explains the minute advancements made over the last few decades in observing cells, revealing how scientists have come and what the future holds for the field.

The ‘humongous fungus’ may be the largest organism on Earth at more than 2,300 acres

Discovered in 1988, when it was only covering 400 acres, this massive colony of Armillaria ostoyae, based in Oregon, has taken hold among the tree roots of the Malheur National Forest. It consists of a vast network of unique long black filaments of fungal tissue called rhizomorphs that grow under the soil and infect tree roots, nourishing the fungus but killing the trees. Researchers believe this fungal growth dates back more than 8,000 years and currently weighs approximately 35,000 tons.

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

A map of every object in our solar system

The infographic from 2020 illustrates the complexity of our solar system, mapping over 18,000 objects including asteroids, comets, planets, and moons. Created by biologist Eleanor Lutz using data from NASA, it shows the non-linear distribution of objects due to the sun's gravitational pull. Objects nearer to the sun are more numerous, forming tighter orbits, while those farther out are fewer and more widely spaced.

B2 models the interactions of air, water, soil, plants and microbes at the LEO

The Landscape Evolution Observatory at Biosphere 2 examines how factors such as climate change, water flow, weathering and community development impact landscape structures comprising 500 metric tons of crushed rock. Research is also conducted at biomes representing savannas, mangroves, coastal fog deserts, oceans and rainforests.

Inhabiting Mars without terraforming might be accomplished with 'worldhouses'

A network of interconnected, airtight bubbles would require several orders of magnitude fewer materials than those required to re-establish the entire planet's atmosphere to resemble Earth. However, the whole network would be compromised by a single micrometeor impact that destroys the air seal.

Long-term evolution experiments use microbe's short generations to speed up selection

With quick generations of microbes, scientists can speed up the evolutionary process, with projects like the LTEE in California running for 40 years and generating 80,000 generations of E. coli.

Visualizing the built world compared to the natural world

In the last century, humans have covered the Earth in 1,300 metric gigatons of built material, known as technomass. That amount is more than the Earth's entire biomass at 1,100 GT, which includes all living organisms. To get a sense of the scale of this comparison, click through this striking, simple visualization showcasing the various organisms comprising biomass as well as the materials making up the technomass.

Why the abundance of RuBisCO in photosynthetic cells may come from its inefficiency

Despite pulling about 115 billion tons of carbon dioxide from the atmosphere to build organic molecules each year, the enzyme instead binds oxygen at least one in five times, needlessly costing cells energy. To compensate for this and its processing of no more than 10 molecules per second—versus thousands processed by a typical enzyme—it's become the most abundant enzyme on Earth.

There may be 74,963 kinds of ice, resulting from water molecules rearranging themselves

The theoretical limit greatly expands the known types of ice, with type Iₕ being the most common on Earth and forming hexagonal crystals. The extreme environments of planets like Uranus and Neptune can create a variety of ice with unique structures and properties, as these conditions can reshape these crystals into new geometries.

What if we killed every mosquito on Earth?

Mosquitoes aren't just annoying, they're deadly. they're also responsible for an estimated 725,000 deaths worldwide, every year. Would it be so bad if we found a way to wipe them out completely? Real scientists have gamed out this hypothetical scenario, concluding it actually wouldn't be that bad. This five-minute video breaks down one way this could happen.

Research suggests a 95-kilometer-wide (59-mile-wide) asteroid impact could boil the Earth's oceans

Even a 1-kilometer-wide (0.62-mile-wide) asteroid can trigger earthquakes and tsunamis on impact with oceans. The overwhelming majority of asteroids that reach Earth are much smaller and burn up in the atmosphere before reaching the ground.

Explore the scale of the universe in this interactive adventure

The sheer enormity of the universe escapes our ability to conceive of its scale, despite the best efforts of human imagination. This interactive provides an intuitive sense of how small we are, from a single astronaut to the Milky Way and beyond.

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.

Coral reefs get their colors from zooxanthellae—microorganisms that line corals' digestive tracts and provide them with sugars in exchange for a home within this protective tissue.

Explore the known asteroids, comets, and spacecraft involved in asteroid studies within our solar system with 'Eyes on Asteroids,' a 3D visualization from NASA.

Apeirophobia is an overwhelming fear of living forever, perhaps stemming from the brain's inability to conceptualize an infinite life.

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.

An investigation suggests a Scottish island became awash in forever chemicals via seafoam and seaspray—raising questions about what that means for the safety of other coastal areas.

Larger animals like giraffes, elephants, and blue whales have developed a unique defense against cancer, a phenomenon known as Peto's Paradox

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

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.

The first line of 'immortal' human cells, which can divide indefinitely and are used in scientific research, was nonconsensually taken from a Black woman.

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.

The syncytiotrophoblast is the outer layer of the placenta and the largest human cell, spanning an area about twice that of a king-sized bedsheet.

While atoms are normally made of protons, neutrons, and electrons, exotic ones have been built with antimatter—alternate versions of normal matter that live for fractions of a second and are about a billion times as rare.

See the 25 of the best photos of auroras from around the world.

Visualize how CRISPR-Cas9—a type of immune system used by single-celled organisms to attack invasive viruses—targets and makes precise changes to a gene's DNA.

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

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

The American cockroach is actually from Africa, an apparent hitchhiker aboard ships carrying enslaved people, with evidence suggesting the bug may have arrived in the New World as early as the 1600s.

Ebola is a filovirus, meaning it resembles a thread under a microscope, though it sometimes twists and can resemble a bowl of spaghetti.

Discover the catastrophic consequences of a failure of the US electrical grid—something that is more likely than many Americans think.

A 2019 Facebook event called on attendees to "Storm Area 51, They Can't Stop All of Us," resulting in countless memes, the creation of a music festival, and eventually the arrests of those who did try to approach the area.

Search a massive database of over 4 decades of clues from the TV quiz show 'Jeopardy!'