etheric turbine

I sometimes play around with VPython/GlowScript to simulate things like planetary orbits, pendulums, spring-mass systems, spacecraft trajectories. VPython is a relatively simple way to get into it. If you've added all the force vectors correctly, you can calculate acceleration, then use Euler's Method or Runge-Kutta to calculate the velocity and position.

Euler's Method
Mass on a Spring Goes boing boing
Elliptical Orbit
Earth and Mars Orbits and Distance to Each Other as They Orbit
Hohmann Transfer from a lower orbit to a higher one.
Simple JavaScript Solar System
Simple JavaScript simulation of Elliptical Orbit

Other Little Programs

Caesar Cypher, a very simple Substitution Cypher
Vigenere Cypher, a more advanced cypher.
Another version of Vigenere that allows spaces and punctuation.

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Basics of Rocketry

Some very basic derivations of equations of rocketry. Why are rockets so big, and the things they launch so small?

Constants
Some constants used in the calculations
Derivation of Tsiolkovsky's Rocket Equation
Delta Vee and Fuel Burned
Reaching Orbit
Multi Stage Rockets
Exhaust Velocity and Specific Impulse
Basic way to estimate average exhaust velocity
Specific Impulse and Thrust of Ion vs Liquid Fuelled Engine
To Low Mars Orbit and back to LEO

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Astronomy: How do we know that?

How do we know what we know about the planets and stars, their distances and masses amd densities and temperature? Even before space flight, scientists could make educated guesses about them just from ground based observations. It's like space CSI.

This section shows how basic geometry and physics were used to deduce properties of astronomical bodies.

Parallax: distance to the planets.
Velocity and Period of an object in Circular Orbit.
Using angle to measure Diameter of a Planet, Distance to its Moons and mass and density of the planet.
Mass and Density of Jupiter and Saturn using their moons.
Parsecs, distance to the closer stars.
Light emission by hot objects: Colour and temperature of stars
Elliptical Orbits Part 1
Elliptical Orbits Part 2
Hohmann Transfer from a lower orbit to a higher one.
Orbital Rendezvous
Why don't nebulas just collapse into one giant ball? Shell theorem and gravity.

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Sufism

Sufi poetry and other material Bushaq the Gastronomer

"The stomach of Bushaq
is so stuffed with pie
He no longer searches for candy
And artichokes just won't fit anymore."

Fakhr e Jahan (Glory of the Universe)

We have been rooted in the skies,
we have been the friends of the angels,
And now we are going back there,
for there is our chief city.

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Tai Chi

Just when the caterpillar thought the world was over, it became a butterfly.

Chuang Tzu

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Books, and thoughts of books

Books, mostly science fiction.

Red Mars by Kim Stanley Robinson

Mars Trilogy, Thirty Years On (Part One)
Mars Trilogy, Thirty Years On (Part Two): Psychological Profiles
Mars Trilogy, Thirty Years On (Part Three): Alternative Economics
Mars Trilogy, Thirty Years On (Part Four): Cultural Diversity vs Economic Hegemony
Mars Trilogy, Thirty Years On (Part Five): Sufis on Mars
Mars Trilogy, Thirty Years On (Part Six): Ultracapitalism