How to write your name on the moon
A detailed investigation into how to write a readable message on the surface of the moon.
Answering the most unlikely question with physics, and explaining some of the subjects I find particularly cool. Learn what it would take to write your name on the moon, or get a clear introduction to rocket flight and Lagrangian mechanics.
How big could you build an enormous concrete cube?
Quite big, it turns out. At least, if you make a lot of simplifying assumptions.
What would it take for all the birds to flap the Earth into a different orbit?
Yahoo Answers brings us the important questions.
How to bat a neutron star into Sagittarius A*
Black hole golf on a galactic scale. Includes a discussion of modelling the Milky Way’s potential well, if you’re into that sort of thing.
The donut packing problem
There is such a thing as a square donut. Placed in a box, will this get you more donut per donut?
How to fly a relativistic rocket somewhere really far away (part 1)
What is the relativistic rocket equation? How do we work it out? What can we do with it?
Spacetime
An introduction to some concepts of special relativity that are useful for rocketry.
How to fly a relativistic rocket somewhere really far away (part 2)
You turn on your rocket. What happens next, in special relativity? (A discussion of accelerated motion.)
How to fly a relativistic rocket somewhere really far away (part 3!)
Putting it all together, what does a relativistic rocket flight look like in practice?
What would I do with a portal gun?
A program of experiments. Hopefully won’t destroy the fabric of spacetime.
Figuring out the solar system
The story of how we came to agree the Earth goes round the Sun, why this wasn’t at all obvious, and what really went down with Galileo and the Pope.
Building a realistic spaceship
You’re a spaceship engineer. What do you have to worry about?
How plausible is this Soviet nuclear-powered airship?
Could an airship really carry a nuclear reactor? Maybe it could, actually.
What IS the canonical momentum?
An introduction to the concepts of Lagrangian mechanics, with pictures instead of lots of maths.
Falling down a tunnel through the Earth
A straight frictionless tunnel through a uniform density sphere, but that’s not quite so catchy.
What are the planets up to?
An introduction to the motion of planets in our solar system, and how that connects to the way they move in the sky.
What could a time traveller do with a smartphone?
Not all that much, actually. A repudiation of the ‘Connecticut Yankee’ genre and exploration of the limits of technology.
What is the shape of the universe?
An accessible overview of the topology of the universe. What’s a ‘topology’? Find out here!
A post on Dyson spheres
Calculations on statite stability, solid shell strength, and temperature.
How hard would it be to farm goats on the moon?
I was asked for advice by an aspiring lunar goatherd. Other moon-farmers might also find something of use.
Time Travel
A discussion of time travel in fiction and exploration of the connections to physics. Causality, tachyonic antitelephones, closed timelike curves, and the question of relative motion.
Do planets close to the sun take more time to transit or less?
A planetary transit is when you can see a planet against the disc of the sun. Here we work out how long that lasts.
Could you launch yourself into space with a giant circular maglev train?
Preferably without getting completely pulverised by extreme acceleration - sorry, Jules Verne.
How to fly a rocket (in space!)
An intuitive introduction to the principles of rocket flight. Minimal maths.
Could we drop all our nukes in the sun?
No, but maybe not for the reason you think.
How much energy can you really get from a battery?
With highly practical methods like fusing every one of its hydrogen atoms, or dropping it in a black hole.
Tsiolkovsky's rocket equation
Derive and use the most important equation in rocket science through a series of bite-sized questions.