Paleontologists apply rules about rock layering, fossilization, and radioactivity to date geological samples

Radiometric dating uses radioactive isotopes to determine the age of objects

By comparing the amounts of parent and daughter isotopes and knowing how long it takes a sample of the former to become the latter, scientists can estimate when an organism was alive or when rocks formed.

Climate proxies reveal past climate patterns using preserved natural evidence

Scientists use physical, chemical, and biological materials preserved in sediments, ice, and fossils to infer historical climate data. These proxies are studied and calibrated against modern climate conditions to interpret ancient environments accurately.

A timeline of human fossil discoveries

A key part of writing a coherent story about our origins is finding and identifying the remains of our ancestors and understanding their significance. Scientists will not always agree on identifications and opinions will change as new find are made and new ways of studying them are developed.

Layers in sediment cores hold clues to Earth’s past climate

By analyzing materials such as pollen and algae within the layers of these cores, which are collected from lakes and oceans, scientists can learn what the environment and climate were like when that layer formed.

Magnetic material in rocks provides evidence of flips in Earth's magnetic field

Volcanic rocks can lock in the direction of Earth's magnetic field as they cool, making them natural recorders of magnetism. Dating rocks and seeing the changing orientation of their magnetic field helps construct a timeline of Earth's magnetic field history.

How paleos dig up dinosaurs

Follow Kelsie Abrams and the dig team from the field to the lab, as they unravel mysteries from the end of the age of dinosaurs.

Fossils form in environments where dead organisms can be rapidly buried

Such landscapes enable corpses to be encased by terrain before significant decay occurs. They are most commonly found in river deltas and sinking coastal regions, where sediments accumulate over time until geological forces expose the areas to erosion, revealing embedded fossils.

What is Archaeology?

If you are up-to-date on your Jurassic Park lore, then you likely already know the answer to this question. But for those of us who didn't delve into the world in dinosaurs, it's easy to assume that professionals who study old stuff likely study the remains of what came before us, right? Find out in this article by the Society for American Archaeology.

A case study of how engineers and geologists at Tullow Oil look for oil reserves

An analysis of surface rocks using aerial and satellite imagery can help narrow the search for crude oil by identifying basins where sedimentary layers have compacted—a key process in oil formation. Surveys that look for variations in Earth's gravitational and magnetic fields consistent with specific rock distributions, or that use sound waves reflected off rock layers—not unlike sonar underwater—can also help map subsurface geology.

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.

Continental drift is supported by matching evidence across disconnected continents

Mesosaurus fossils are found in South America and Africa, but these freshwater creatures could not have travelled across the ocean between continents. Rock layers in the Appalachian Mountains match those seen in Europe, indicating that the mountain belts were once connected.

How do archaeologists determine how old something is?

How old is the item in the photo? According to the MET, it dates back to the 3rd to 5th century. Archaeologists don't just file artifacts under generic time frames such as "ancient" or "super old." They're often able to pinpoint the era or century...

A primer on reading the rock layers of roadcuts

Road construction often requires cutting through layers of rocks, coincidentally exposing millions of years of rock formation. This simple guide introduces basic rock types, what causes curves and folds, and the major rock formations in regions around the US.

The oldest DNA recovered so far is 2 million years old

The oldest DNA recovered so far is about 2 million years old and has given scientists an unadulterated peek into ancient history. This nine-minute video explores the findings and implications of the DNA, which was pulled from frozen soil in...

Herd behavior has been seen in 193-million-year-old dinosaur fossils

Scientists excavated eggs, juveniles, and adult remains in Patagonia, all arranged by age group. The organization into structured groups may have contributed to evolutionary success by consolidating eggs in one location to make defending them easier.

Chronological versus biological age

Science has come to understand different types of aging. What we call age is simply the number of years since birth, or chronological age. At the cellular level, biological aging happens at different rates for different people, and explains why some seem to age more quickly (or slowly).

What did Earth look like when dinosaurs roamed?

The face of the Earth isn’t remotely the same as when the dinosaurs ruled the roost. The passing of millions of years, plate tectonics, and a spotty track record with asteroid collisions have changed the planet’s surface. Use this interactive globe to see what the Earth looked like millions of years ago.

Synchrotron radiation has revealed the fur color of creatures millions of years old

When electrons are accelerated in the loop, they produce intense X-rays that can reveal properties of a sample struck by them, just as X-rays can be used to show bone structure in humans. Studying the reflected light from fossils can uncover the presence of known pigmentation compounds.

Delays in the decay of unstable particles provide evidence for time dilation

Physicists used the muon half-life measured in labs to predict how many should reach detectors on Earth's surface after their production in collisions between atmospheric molecules and cosmic rays. Higher detection rates were consistent with a longer half-life due to slower movement through time.

Earth's core is about 2.5 years younger than its surface according to relativity

Due to differences in where objects are located within gravitational fields, time will run at different rates, which has major impacts on technology that relies on synchronization. For example, GPS satellites run about 38 microseconds faster every day than clocks on Earth's surface, resulting in GPS discrepancies of about six miles, were it not for software corrections.

Scientific advances have transformed understanding of Stonehenge’s builders

Techniques such as radiocarbon dating, DNA analysis, and isotopic testing have revised scholars' understanding of Stonehenge. This article presents evidence suggesting that societies were more cooperative and less violent than earlier theories had suggested.

Niagara Falls flows over 400-million-year-old layered rock

The falls cut through distinct layers of ancient rock: a hard cap of Lockport Dolomite sits atop softer layers of Rochester and Queenston Shale. This structure allows the falls to maintain a steep vertical drop as erosion undercuts the caprock.

Comets serve as time capsules of the early solar system

The frozen objects preserve the molecular composition of the solar system's formation, dating back about 4.6 billion years. Spectral analysis of the gases they release when heated upon approaching the sun in eccentric orbits reveals this composition and helps assess solar system formation models.

Watch 1 billion years of tectonic plate movement in 40 seconds

Researchers at the University of Sydney developed the model, incorporating changing plate boundaries rather than just moving continents, to better understand the changes to biological and climatic systems throughout Earth’s history.

Billion-year-old Arctic fossils suggest Earth had fungi far earlier than previously thought

Named Ourasphaira giraldae, this new species of fungus, reported in 2019, was found in the Grassy Bay Formation in the Canadian Arctic. It pushed the fossil record of fungi back by about half a billion years since the oldest previously recognized fungi fossils came from the Rhynie chert, a Scottish site that dates back roughly 400 million years. This fungal discovery also suggests that fungi may have occurred on land much earlier than plants, raising questions about what ancient fungi used for nourishment.

Minerals, crystals, rocks, and gems explained

Have you ever wondered what differentiates a mineral from a rock or a crystal from a gem? This three-minute video from the American Museum of Natural History elaborates on the unique properties and compositions that separate minerals, rocks,...

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.

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.

Graffiti dates back to at least ancient Pompeii, where citizens scrawled messages to one another on public walls

Radioactive elements can introduce software errors because the ionizing radiation they produce can detach electrons from atoms, and computer code relies on the distribution of electrons.

Hear 50 years of iconic hip-hop samples, the genre's foundational looped tracks

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.

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

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

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.

Researchers believe the brain consolidates memories, processes emotions, and plans for the future during dream states

Explore the history, structure, and species of Australia's Great Barrier Reef with this interactive journey narrated by Sir David Attenborough.

See how fireworks are made and learn how metals like magnesium and copper are responsible for different colors.

Some Pokémon have been named after real and fictional organisms, while some real-world species have been named after Pokémon, such as Chilicola charizard and Binburrum zapdos.

Corals are themselves not coral reefs—the term refers to the tiny marine invertebrates that build the rigid reef.

At the beginning of the 20th century, a group of young men ate standard American food—replete with food additives like borax and formaldehyde—as part of government research to better understand food safety.

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

Learn how to read a prospectus, the juicy document that any company must file with the SEC before going public.

Objects can be 3D printed with light by projecting 2D computerized tomography (CT) scans onto rotating cylinders of resin, which solidify upon exposure.

Doctors differentiate between a phobia and fear by asking patients whether their fear interferes with their day-to-day activities.

The US Constitution is widely regarded as the longest-standing written national constitution still in force—see how it has influenced rights worldwide.

The concept of phantom limbs, the perception that amputated limbs are still present, dates back to a French military surgeon in the 16th century.

The distributor behind 'Rocky Horror' pulled the film from its scheduled national release, believing it would be a failure, though it eventually amassed a dedicated fanbase through midnight showings, a trend that continues over 50 years later.

Gerrymandering works through two techniques: cracking opposing voters across districts to dilute their power, and packing them into a few to waste their votes in lopsided majorities.

Some coin denominations have ridges etched on their sides, partly to prevent counterfeiting, in a practice called 'reeding.'