surface area

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.

Rune Skovbo Johansen explains Surface-Stable Fractal Dithering, a technique he invented and released as open source. It makes dithering stick to 3D surfaces and covers the experiments and shortcomings along the way, inspired by Return of the Obra Dinn.

Destin Sandlin of Smarter Every Day explains how a US Navy nuclear submarine surfaces through Arctic ice, filmed during the ICEx exercise. It shows ballast and control systems and the physics involved.

Explains the proposed NASA JPL plan to use the Sun as a gravitational lens, sending solar sail craft to its focal region to image an exoplanet's surface. It covers the distances involved, how imaging with the Sun would work and the mission design.

A 10-minute 3Blue1Brown chapter explaining the determinant as the factor by which a linear transformation scales area or volume. It builds the idea geometrically with animations before any formulas.

Sabine Hossenfelder explains how the greenhouse effect actually works, given that infrared is mostly absorbed low in the atmosphere already. She walks through why more CO2 still warms the surface.

Mark Handley of UCL explains, with simulation visualizations, how early Starlink satellites without inter-satellite links could still give low-latency wide-area communication by hopping via ground relays. He shows it can beat fibre on many long paths.

PBS Space Time episode on the black hole information paradox, covering how black holes seem to destroy information, the no-hair conjecture and the proposed role of the event horizon. It is part of a series on black holes.

Isaac Arthur examines options for colonizing Venus, from vast floating habitats in the temperate upper atmosphere to full terraforming of the planet. It is a long-form speculative futurism episode in his solar system colonization series.

A two-minute clip in which Milton Friedman uses a humble pencil to show how thousands of strangers across many countries cooperate, without central direction, to make a simple product. It is a short visual version of the 'I, Pencil' essay's argument about free markets and dispersed knowledge.

Randall Munroe of xkcd answers what would happen if you swam in a spent nuclear fuel pool, and how much radiation you would receive at the surface versus at depth.

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.

A short TED-Ed animated lesson by Anita Collins on what happens in the brain when people play a musical instrument. It argues that playing engages many brain areas at once, like a full-body workout, with long-term benefits.

Not Just Bikes reflects on five years in the Netherlands and tours small towns and cities, from Haarlem to Veenendaal. It argues that good urbanism with walkable streets, bike infrastructure and transit is found almost everywhere there, not just in Amsterdam.