orbital cycles

Mathologer explains epicycles and complex Fourier series, inspired by an animation of Homer Simpson drawn with epicycles. It covers the shape of the Moon's orbit around the Sun and how to make your own epicycle drawings.

An animated 44-minute summary of Ray Dalio's book Principles for Dealing with the Changing World Order. It lays out the Big Cycle of rising and declining nations, covering debt cycles, internal conflict, and shifts in global power over the past 500 years.

Isaac Arthur explains the orbital ring, a megastructure launch-assist system that could move bulk cargo cheaply to orbit and beyond. He compares it with space elevators and discusses power transmission.

FortNine argues that e-bikes have injury rates and speeds closer to motorcycles than to pedal bikes. It argues riders should treat them with similar safety gear and caution.

Eager Space examines the practicality of putting data centers in orbit, walking through three scenarios with cost calculations and the launch cost reductions that would be required.

A short animation reconstructing a planet's looping orbit using Ptolemy's epicycles and deferents, with the epicycles tracing out the face of Homer Simpson. It shows how enough circles can reproduce nearly any shape.

Dan Britt lectures on the history of climate, covering orbital cycles, ice ages and conditions millions of years ago. It frames current climate debate with deep-time context.

Scott Manley uses a realistically scaled Kerbal Space Program setup to show why dropping something into the Sun is far harder than it sounds. It demonstrates the need to cancel orbital velocity.

EEVblog's Dave Jones critiques Reflect Orbital's plan to sell sunlight to solar farms after dark using orbital mirrors. He walks through the numbers to show the idea does not work out.

An animated Gabbard diagram of objects in low Earth orbit from 1959 to 2021, showing altitude over time. It highlights major debris-generating events and how low-altitude debris decays out of orbit.

Ray Dalio's 30-minute animated video explains how the economy works through credit, debt, interest rates, and short- and long-term cycles. It is based on his template for understanding the economy.

Scott Manley explains the plumbing of rocket engines, including pressure-fed, gas generator, expander and staged combustion cycles. He shows why more complex designs exist and what they gain.

SpaceX's own compilation of failed orbital booster landing attempts, set to sound, showing the crashes before landings succeeded.

FortNine looks at why Tesla Autopilot has rear-ended motorcyclists, speculating that the vision system misreads motorcycle taillights as a distant car. It argues that radar and other sensors would help.

A motorcycle safety video on the SMIDSY (sorry mate, I didn't see you) accident, explaining the perception and optical illusion that makes drivers fail to see riders, and how riders can spot the signs and avoid it.

FortNine explains the economics of the dealership model, arguing that dealers absorb inventory risk and help manufacturers' finances. It looks at whether cars and motorcycles could be sold more cheaply without them.

Scott Manley examines why SpaceX, Google and others are looking at orbital data centers. He walks through the economics, heat rejection and solar power arguments, with links to the Lumen/Starcloud and Google Suncatcher papers.

Scott Manley analyzes the idea of putting data centers in orbit, prompted by Lumen Orbit's funding. He examines the claimed advantage of constant solar power against launch cost, cooling and mass.

In her final days as ISS commander, Sunita Williams gives an extensive tour of the station's modules and research facilities, narrating the work done aboard.

A Capella Science parody of Ed Sheeran's Shape of You, rewritten about molecular bonding and orbitals and sung a cappella.

A short minutephysics video explaining why bicycles stay upright. It looks at gyroscopic precession, head angle and centre of mass, and shows that bikes self-steer toward the direction they lean.

Not Just Bikes explains why upright Dutch-style bicycles are comfortable and practical, and why they are rare outside the Netherlands.

A three-minute minutephysics video on the orbital mechanics of why crashing into the Sun takes far more energy than leaving the solar system.

AI Addict films a Tesla FSD Beta 8.2 drive through Oakland, annotating close calls, disengagements, pedestrians and wrong-lane moments with timestamps.

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

3Blue1Brown introduces Fourier series, from the heat equation to drawing arbitrary shapes with rotating circles. It builds a visual intuition for decomposing functions into sine waves.

FortNine explains how Harley-Davidson ended up in decline, from a narrow lifestyle niche and an aging customer base to the pandemic hitting a company already in trouble.

A clip from the 2011 film Margin Call in which a firm's CEO, played by Jeremy Irons, tells a senior executive about the cycles of financial crashes. Kevin Spacey's character says he wants out, and the scene ends on the line that it is just money.

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.

Bret Copeland, in an astronaut costume, gives an energetic talk on how the Space Shuttle landed from orbit, including reentry and the unpowered glide. It includes real-time landing footage with HUD and audio.

Nine minutes of unedited footage of a very busy bicycle and car crossing at Korte Prinsengracht and Haarlemmerstraat in Amsterdam. Cyclists, pedestrians and cars flow through without traffic lights.

The full webcast of SpaceX's Falcon 1 Flight 4, the first privately developed liquid-fueled rocket to reach orbit, on 28 September 2008. It includes the crew's cheering and Elon Musk's statement afterward.

California Superbike School demonstrates its 'No B.S.' bike, which has fixed handlebars so riders can only steer with body lean. It illustrates how little control that gives compared with countersteering.

Scott Manley explains the thermal balance of spacecraft and how a satellite could be configured to radiate away the heat from datacenter-scale computing in space. His rough numbers suggest it is feasible.

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.

An animation presenting a non-standard helical or vortex model of the solar system, in which the planets trail the Sun through space instead of orbiting in flat circles. The model is a non-conventional view that the author says differs from standard diagrams.

Thunderf00t critiques SpinLaunch, the startup that proposes flinging payloads to space with a giant centrifuge. He argues the physics and engineering do not hold up.

A video showing a virtual camera built in Blender that simulates lenses and film layers using path tracing, to make physically modeled photographs.

Danny MacAskill tries to destroy carbon fiber bike wheels by riding trials tricks through downtown Glasgow, including on bare rims on concrete.

Michael Steil's 33c3 talk explains essentially everything about the Game Boy: CPU, video hardware, peripherals, and the tricks used by games and demos. It revives the era of counting clock cycles around hardware limits.