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

The history of Earth's breathable atmosphere, made possible by photosynthetic bacteria

Between 3.2 billion and 2.8 billion years ago, threadlike microorganisms called cyanobacteria began consuming available water vapor, carbon dioxide, and sunlight to produce oxygen. However, molecules released from Earth's interior by volcanoes consumed this oxygen via chemical reactions, preventing it from accumulating until volcanism had sufficiently decreased about 2.4 billion years ago.

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.

Hypotheses on the origins of Earth's water, from comets and asteroids to magma oceans

Before Earth's atmosphere formed, any liquid water would have boiled off, preventing the accumulation of water early on to create today's oceans. Planetary scientists continue to debate whether this water was delivered later from comet or asteroid collisions or via reactions between iron oxide in Earth's molten surface and hydrogen gas from the planetary nebula.

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.

Humans have existed for just 0.004% of Earth’s history

Born from the remains of the molecular cloud that birthed the sun, Earth experienced planetary-scale collisions, asteroid impacts, and lava seas. Life became possible after the planet cooled and formed a thin crust, atmosphere, and oceans.

The cycling of carbon via tectonic activity may have facilitated life on Earth

Plates sinking into Earth’s mantle pull carbon from the surface, helping stabilize the atmosphere and climate by removing greenhouse gases from volcanic eruptions. At the same time, magma is a significant contributor of heavy metals and other crucial minerals for life to the surface.

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.

Learn how the Earth was made

Four and a half billion years ago the Earth formed from dust in space to become a molten ball of rock orbiting the sun. Travel back in time to investigate how the Earth was made.

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.

How microorganisms transformed into crude oil over millions of years

Despite the misconception that oil comes from dinosaurs, the nonrenewable resource forms when tiny organisms are subjected to high pressure and high temperature while buried under layers of sediment over tens to hundreds of millions of years. During this time, they become a mixture that is almost entirely hydrocarbons, which can be harnessed and refined.

About 99% of Earth's atmosphere is made of nitrogen and oxygen

At 78% and 21% respectively, the two elements are followed by argon with almost 1%. Trace amounts of other molecules, including greenhouse gases such as methane and carbon dioxide, and particulate matter such as dust and pollen, make up the remainder of the atmosphere's contents.

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.

Learn about endoliths, the polyextremophiles that thrive inside rocks

These organisms include species that live in Antarctica, where they perform photosynthesis using light and water that makes it through pores in sandstone. Others residing in Earth's crust can survive temperatures reaching 60 degrees Celsius (140 degrees Fahrenheit) while generating energy through chemical reactions involving nutrients and gases trapped in rocks.

How the sun heats the Earth

We all know it: Without the sun's heat, the Earth would be uninhabitable. So how does it work? The sun fuses roughly 600 million tons of hydrogen every second, the energy from which bursts out into space—including toward our planet. Our atmosphere...

Exposed concrete led to oxygen depletion within Biosphere 2

Instead of being absorbed by plants through photosynthesis to produce oxygen, significant amounts of carbon dioxide were taken up by the calcium hydroxide in the concrete, trapping the oxygen in calcium carbonate and water. This concrete was sealed before the start of the second B2 mission.

Rubisco, the crucial enzyme powering photosynthesis

Photosynthesis is the crucial process by which plants absorb sunlight, take up water, and breathe in carbon dioxide, prompting chemical reactions that result in the byproducts sugar and oxygen. A key enzyme, rubisco, is responsible for it all, but it is inefficient. This video explores the key protein and reveals fascinating facts about oxygen and photosynthesis.

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.

Fusion reactions and radioactive decay produce elements inside stars

Hydrogen, present since the early universe, serves as fuel for the proton-proton chain, producing helium, which is then incorporated into the CNO cycle to produce carbon, nitrogen, and oxygen. Additional fusions of helium with these elements and subsequent decays via the alpha ladder produce elements up to iron and bismuth.

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.

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.

Geode formation begins with trapped gas bubbles in igneous or sedimentary rock

Over thousands or millions of years, water seeps into the cavity created by the bubble and deposits minerals, which slowly build and crystallize into quartz, agate, amethyst or other crystals.

Create anything from the elements in Little Alchemy 2

Various ancient cultures believed the most abundant substances in the world were its basic elements: earth, water, air, and fire. We may know better now, but you can make almost anything from those four things. Little Alchemy 2 is a fun, cartoonish game that allows users to create more complex items from simple substances.

How artificial photosynthesis can help make plastics and fuels using sunlight

These systems link a molecular light absorber to a catalyst that can synthesize fuels—such as ethanol—and ethylene, a precursor to plastics, in a carbon-neutral manner. Because these byproducts have greater energy concentrations than the carbohydrates produced by photosynthetic organisms, research is ongoing to engineer the necessary catalysts.

Metals can be welded together in space without needing heat

On Earth, oxygen naturally reacts with metals to form an oxide layer on their surface, which prevents two different pieces from fusing when they come into contact. If the layer is worn away without oxygen to replenish it, metals can instead stick together upon impact—a phenomenon known as cold welding.

Why 75% of ocean animals glow

About 75% of ocean creatures can make their own light. It's called bioluminescence—and it all comes down to a special chemical reaction happening inside their bodies.

Landfills capture methane gas and convert it into usable energy

As organic waste breaks down underground, it produces landfill gas that is roughly 50% methane. That gas can be captured and used to generate electricity or provide heat for nearby homes and businesses.

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

Stars appear to twinkle because turbulence in the motion of molecules in Earth's atmosphere causes light to bend and wiggle rapidly on its way to the surface—a phenomenon called scintillation.

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.

Learn more about the history of fireworks, which dates back to an accidental invention during an alchemist's quest for information about immortality.

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.

Watch how deep-sea mining equipment collects and processes polymetallic nodules—metal-rich, potato-shaped rocks—from the ocean floor and creates environmentally damaging plumes of sediments.

The use of fungi to detoxify land and water—a process known as mycoremediation—has been used to clean up natural resources affected by the 2025 California wildfires.

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.

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.'

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

Pure water does not conduct electricity because this flow of energy requires the movement of charged particles, and water is a neutral molecule.

The word 'jazz' evolved from 'jasm,' 19th-century American slang for 'energy'

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.

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

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

An initial public offering or 'IPO' is the process of a private company becoming public by putting shares of the company on the stock market for purchase.

Studies suggest when you sleep is as important as how much you get, and syncing with your circadian rhythms may lead to less fatigue and improved long-term health outcomes

The price of gas is a composite made up of several different factors, with the federal gas tax making up less than 20% of what drivers pay at the pump.

After the Boston Tea Party, colonists switched to coffee, which became the main morning drink for revolutionaries.

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 animatronic shark from Steven Spielberg's 'Jaws,' the first modern blockbuster, was a complex underwater apparatus called 'Bruce.'

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.

Children are now three times more likely to say they want to be a YouTuber when they grow up than an astronaut, with some even attending 'YouTube camps' that teach kids how to create content for the platform.

A researcher recently discovered an interview from 1967 between groundbreaking journalist Joan Didion and the Grateful Dead, years before the band became an institution.