earth

PBS Space Time examines the Silurian hypothesis, the idea that an industrial civilization could have existed on Earth before humans. It looks at what traces such a civilization might leave in the geological record.

A short explainer from Nat and Friends on where Google Earth's 3D imagery comes from, how it is stitched together, and how often it is updated. It describes aircraft carrying camera rigs and photogrammetry that turns the photos into 3D models.

David Kipping presents his proposed Terrascope, a telescope that uses Earth's atmosphere as a lens to achieve enormous magnification. He covers the history of telescopes and his path to the idea, plus Sol-scope and Jupiter-scope variants.

Practical Engineering explains Mechanically Stabilized Earth, where layers of reinforcement make soil strong enough to hold heavy loads, shown with a sand structure supporting a car. It notes that MSE walls are everywhere in infrastructure.

Veritasium visits Chernobyl, Fukushima and other places to find who on Earth is exposed to the most ionizing radiation. The answer turns out to be surprising and puts radiation risk in context.

An animated Kurzgesagt explainer on bacteriophages, viruses that kill bacteria, covering how they infect and burst cells and their potential as therapy against antibiotic-resistant bacteria.

A SciShow episode in which Hank Green introduces five of the most dangerous chemicals, from lethal toxins to substances that explode on contact. It is an entertaining overview of extreme chemical hazards.

Arthur Keller gives a roughly half-hour crash course on environmental collapse, covering exponential growth, carrying capacity and ecological overshoot.

Kurzgesagt's hour-long animated film that compresses Earth's 4.5 billion year history into one hour, roughly a million years per second. It follows the evolution of life through to humanity's tiny final stretch.

Soup Emporium's deep dive argues that Yellowstone is not a ticking timebomb. It goes through uplift and subsidence, earthquakes and what the caldera really is, to rebut supervolcano doom claims.

Kurzgesagt asks whether advanced civilizations could have existed on Earth in the deep past and left little evidence. It looks at time as a dimension for searching for alien civilizations and the limits of the geological record.

A BBC Earth clip from Super Powered Owls in which the team uses sensitive sound equipment to compare owl flight with other birds. It shows why owls fly almost silently.

A short clip from Carl Sagan's Cosmos in which he explains how Eratosthenes measured the circumference of the Earth using shadows in two Egyptian cities. It is a clear, visual account of an ancient scientific feat.

Matt Parker of Stand-up Maths asks whether a country's reported land area accounts for hills and mountains, working through how surface area depends on the resolution of elevation data. It follows up on a question from a viewer and work by researchers who measured it.

Curious Droid asks what traces human civilization would leave in the geological record 65 million years from now. It considers how thin the fossil record of humanity might be.

Practical Engineering explains what a 100-year flood actually means, combining statistics, hydrology and how society treats risk. Grady walks through local drainage infrastructure and the caveats in estimating flood probability.

Engineering Explained examines new research suggesting corn ethanol in US gasoline may emit as much or more carbon than gasoline. It covers the Renewable Fuel Standard and why ethanol was assumed to be a green fuel.

Practical Engineering explains why San Francisco's Millennium Tower is sinking and tilting, covering how geology and foundation design (friction piles in the Colma Formation) affect skyscrapers. It also covers the fix being attempted.

Tom Scott explains how decades of deep coal mining sank parts of Germany's Ruhr Valley and changed its drainage. Pumps run by Emschergenossenschaft must now work permanently to keep towns and cities from flooding.

Tom Scott visits the Strid at Bolton Abbey in Yorkshire, a deceptively narrow stretch of river with dangerous currents. He covers its reputation and the 12th-century legend of the Boy of Egremont.

Tom Scott visits the US National Helium Reserve in Amarillo, Texas, and explains why headlines that the world is running out of helium are misleading. He covers the Federal Helium Program and its planned privatization.

NFPA video in which wildfire researcher Jack Cohen explains that embers (firebrands), not the flame front, are the main cause of homes igniting in wildfires. He shows how landscaping and removing debris around the home reduce risk.

A minutephysics explainer showing that the Moon's path around the Sun is not a spiral but closer to a 12-sided polygon with curved corners. It argues the Moon arguably orbits the Sun rather than the Earth.

Kurzgesagt explains how accumulating space junk could trigger a collision cascade (Kessler syndrome) that makes launches too dangerous and traps humanity on Earth.

Veritasium's explainer on entropy, presented as one of physics' most important and least understood concepts. It uses examples such as heat engines and the sun's energy flowing through the Earth.

Kurzgesagt lays out a speculative plan to terraform Venus, covering its hostile atmosphere and how it might be made Earth-like, with a sources page linked.

Veritasium explains why many real-world systems follow power laws rather than normal distributions. It covers self-organized criticality, with simulations of sandpiles, magnetism and forest fires.

An Isaac Arthur episode on arcologies, self-sufficient habitats that could house whole cities, on Earth or on harsh worlds. It covers how such structures might work and what limits their size.

Terence Tao and Grant Sanderson of 3Blue1Brown walk through the cosmic distance ladder, showing how humans measured distances from the Earth to the Moon, Sun, planets and beyond. It includes animations and the history behind each step.

An episode of Journey to the Microcosmos, hosted by Hank Green, about diatoms, single-celled algae with glass shells. It covers their role in producing a large share of Earth's oxygen and their uses in beer filtering, paint and kitty litter.

Isaac Arthur explores space-based solar power, in which satellites beam energy down via microwaves to rectennas on Earth. He discusses feasibility, profitability and its role in spurring space colonization.

Kurzgesagt explains the skyhook, a rotating cable with a counterweight that could catapult spacecraft from Earth orbit toward deep space. It covers why it would make space travel cheaper and more efficient.

A Kurzgesagt animation on supernovae, the most powerful explosions in the universe. It explains their role in creating elements and what would happen to Earth if one occurred nearby.