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...

Abiogenesis explains how Earth's natural processes could have formed organic matter

The theory details how chemical interactions in hydrothermal vents and shallow ponds billions of years ago could have created lipids, proteins, and RNA. As these interactions involve water, life is thought to have started in oceans.

Before discovering cells, life was believed to emerge suddenly from inorganic matter

Popularized by Aristotle in the 4th century BCE, spontaneous generation was used to explain phenomena like mice appearing in seemingly sealed grain storage. The invention of the compound microscope in the late 16th century led to the identification of cells as the basic unit of life, but it was not until 1855 that their origin from preexisting cells was established.

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.

Exoplanet atmospheric gas patterns may indirectly provide evidence for life

When searching for life beyond the solar system, scientists first determine the range of distances from a star that liquid water—believed to be essential for life—can be found. Within this habitable zone, the presence of specific molecules in an exoplanet's atmosphere—detectable through spectral analysis—can indicate the presence of living things known to produce those compounds.

The key ingredients to life on Earth—and elsewhere

Life can only arise in incredibly specific conditions, an abundance of certain substances like water and phosphorus, lots of time, and the right proximity to a heat-and-light-providing star. These two experts on evolution of life say above all, life requires luck. Here's a list of eight ingredients to life.

Questioning the results of life on K2-18b

An analysis of the atmosphere of an exoplanet called K2-18b identified the presence of biosignatures—molecules that are created by living things on Earth. This discovery may indicate life exists beyond Earth, but the lack of environmental data complicates the interpretation of results.

Can we speed up our metabolisms?

Listen to this 31-minute podcast to better understand what science knows and doesn't know about metabolism, as well as the only thing that seems capable of changing it. Scientists understand that the difference between a so-called “fast” and “slow” metabolism does not affect one’s ability to lose weight.

Is metabolism related to weight loss?

Read this article to better understand metabolism and why doctors say it's only one piece in the puzzle to managing weight. Metabolism breaks down and converts what we consume into energy, which provides fuel for all of our body's functions—both...

Biosignatures are the chemical fingerprints astrobiologists search for to find life

The 21st century has introduced advances making telescopes, cameras, and computers powerful enough to detect the presence of molecules associated with biological processes in distant atmospheres, expanding the search for life to include unreachable worlds.

Spontaneous combustion involves an object igniting on its own

Even without matches, sparks, or external flames, exothermic chemical or biological reactions can increase the internal temperature of objects to the point where they reach a threshold temperature that can cause them to catch fire. Running batteries and fermenting bacteria within compressed materials can build this heat and cause combustion.

Evidence suggests the first cells on Earth were bacteria

About 4 billion years ago, these single-celled organisms harvested carbon dioxide and sunlight to produce their own food and oxygen, setting the stage for the evolution of oxygen-breathing life forms. Archaeabacteria, which thrive on inorganic molecules in extreme habitats on Earth today, were also among the earliest organisms.

Metabolism, a collection of chemical reactions at the cellular level, processes food and converts it into energy to power the body.

A four-billion-year-old meteorite reignited the debate about life on Mars

Recovered from Antarctica in 1984, ALH84001 contained organic compounds, magnetite and iron sulfide grains of potential biological origin, and features that resembled fossilized bacteria. With technological advancements, scientists found abiotic origins for these features in the following decades.

Early Earth lifeforms likely made energy via mineral reactions, not sunlight

Earth's initial atmosphere was filled with carbon dioxide, methane, and water, with most oxygen locked away in the rocky crust. Over time, bacteria evolved to slowly release that oxygen into the atmosphere by breaking down rock.

Astrobiology is the study of life's origins and the search for life beyond Earth

The field incorporates observational missions to find and classify exoplanets—planets orbiting stars besides the sun—the probing of Earth's most extreme environments to learn what conditions allow life to exist, and theoretical and lab work to identify and analyze potential biochemical signatures.

Mold growth in space raises the hypothesis of life being brought to Earth

Panspermia suggests that life could be carried throughout the cosmos by asteroids, comets, and other objects, but it requires organisms that can withstand the extreme cold of space travel, stellar radiation, lack of water, and intense heat of planetary impacts. The discovery of mold on the International Space Station and experiments showing it can withstand radiation in outer space-like conditions increase the plausibility of the hypothesis.

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.

Learn about historical uses of bioremediation, the oldest cleanup method on Earth

Biochemical reactions that decompose complex molecules into simpler ones have occurred on Earth for as long as life has existed and have gradually transformed the planet into a celestial body that is increasingly habitable to greater biodiversity. Along the way, modern, human-made bioremediation techniques began to take shape in Santa Maria, California, in the 1960s.

The discovery of the first extremophile and how it revolutionized DNA analysis

While investigating samples taken from within and around the hot springs at Yellowstone National Park, microbiologist Thomas Brock discovered Thermus aquaticus, a microorganism that thrived in hot water. It contained an enzyme called Taq polymerase, a critical molecule in polymerase chain reaction—a molecular photocopier that amplifies genetic signals to improve medical diagnostics.

Why extremophiles may play an important role in terraforming Mars

Possessing unique biochemicals that can detoxify extreme environments and resilience against the Martian surface that is lethal to humans, scientists are exploring whether colonies of these organisms can transform small areas of the Red Planet into future habitats for humans. Extremophiles may also be best equipped to serve as microscopic factories for the fabrication of essential polymers.

Read the NASA overview of the results of Viking’s biological experiments on Mars

Three experiments on the Viking 1 and 2 landers searched for signs of metabolic activity in soil samples, indicating the presence of microorganisms. No definitive evidence of life was found in any experiment or lander imaging.

What is metabolic rate?

Read this article to better understand the concept of metabolic rate, which is defined as the amount of energy expended by an organism over the course of a day. Basic metabolic rate (or BMR) is this metabolic rate at rest, during which the body only...

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.

RNA may have allowed life to exist before DNA

The emergence of living organisms from non-living matter—abiogenesis—requires both a molecule that encodes genetic information and proteins that perform biochemical processes. However, because DNA and protein depend on one another, some biologists theorize that RNA, which can both store information and perform functions, preceded both and originated life.

Scientists have created a cell from scratch—called a SpudCell—proof-of-concept work that a lab-made cell can feed, grow, and replicate like a natural cell.

JWST might spot life faster on ocean worlds than Earth-like ones

Unlike Earth-like planets, hycean worlds with thick hydrogen atmospheres and deep oceans could allow biosignature gases like methyl halides to accumulate in detectable levels. These gases, linked to microbial life on Earth, are easier for the James Webb Space Telescope to identify than traditional markers like oxygen or methane.

In 2026, researchers at the University of Minnesota created the world's first synthetic cell—a cell made from non-living chemical components—that can eat, grow, divide, and compete with other cells for resources.

The reason some people love exercise may be because of their microbiome

Certain gut microbes in mice trigger dopamine release and drive motivation to exercise more. Scientists are investigating whether humans carry similar microbial patterns that influence our natural inclination towards movement, exploring how unseen microbial ecosystems may shape mammalian fitness behavior and reinforce innate reward pathways. (Some users may experience a paywall.)

Where do genes come from?

There are many more genes on Earth today than when microbial life first spawned on the planet about four billion years ago. Many of these newer genes grew from genetic mutations, misprints that slowly drift from the original blueprint via cellular division. If these mutations drift far enough, they can establish a new family of genes, though this process can take well over a million years.

Inside the community movement behind DIY synthetic biology

Margaret Talbot spotlights the rise of DIY biology in community labs, where amateur scientists—often outside formal institutions—create everything from insulin to prosthetic prototypes. These grassroots biohackers challenge traditional science by pursuing open, accessible innovation, raising questions about credibility, ethical oversight, and acceptance by mainstream researchers.

Extremophiles were likely to have been Earth's first, and are expected to be its last, organisms

Their ability to survive in an enormous range of environmental conditions, including some resembling what has been modeled to have existed relatively shortly after Earth's formation, makes them the leading candidates for enduring the increasing solar intensity and the subsequent effects (e.g., zero-oxygen atmosphere, evaporated oceans) expected in the coming billions of years.

Learn how chloroplasts—the photosynthesis factories—may have once been independent cells

Possessing DNA of their own that differs from that of their host cell and surrounded by cellular membranes like those observed in bacteria, chloroplasts are believed to have evolved from a cyanobacterial cell. The endosymbiotic theory explains that these organelles were absorbed into larger cells, leading to the photosynthetic cells seen today.

Read the academic article explaining how ancient smells can be dissected and recreated

This paper explores how biomolecular data on past scents can be teased out and then transformed into olfactory museum experiences, adding another component to our understanding of archaeology.

The role of fire in the evolution of humanity's big brains

Roughly 1.5 million years ago, the brain size of our hominin ancestors exploded. To understand why, Richard Wrangham posited the cooking hypothesis, arguing the adoption of fire as a means to cook food had a lasting impact on our ability to digest...

'Endoevolution' refers to the Darwinian selection happening continually inside us

The term, coined by Roxanne Khamsi in her 2026 book "Beyond Inheritance: Our Ever-Mutating Cells and a New Understanding of Health" describes the idea that evolution does not just occur across generations of humans. Instead, mutated cells continuously compete with healthy ones in our bodies, with implications for our tissues and health. Khamsi says these autocorrections are essentially natural gene therapy. 

A look at hydrothermal vents, where barophiles and hyperthermophiles survive boiling water

Discovered in 1977 during an exploration of the Galapagos Rift, these seafloor openings spew hot magma and chemicals that heat seawater to hundreds of degrees. Without the sunlight found at depths of less than 1,000 meters (3,281 feet), extremophiles in these environments convert released chemicals into energy to survive, alongside surviving extreme pressures.

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.

Aliens may be closer to Earth than scientists have previously assumed

The hunt for extraterrestrial life is often associated with traveling far into the depths of space for clues. But answers could be closer than we think. Modern space missions have demonstrated our capability of sending probes beyond the solar system, making it plausible that other civilizations could do the same.