Space 01
How Much Does a Teaspoon of Neutron Star Weigh?
A 5 mL teaspoon of average neutron star weighs about 1.9 billion tonnes, not the 10 million often quoted. The density math, and what it would do on Earth.
Space
Space 02
How We Know 3I/ATLAS Is Interstellar: Orbit Math
3I/ATLAS has eccentricity 6.1 and leaves at 58 km/s. We compute its orbital energy, compare 'Oumuamua and Borisov, and show why no planet could fling it.
Space 03
Why Is James Webb at L2? The Physics, Computed
Webb orbits L2, 1.5 million km out, so Sun, Earth and Moon stay on one side. L2 isn't where gravity cancels, and sitting at it means an endless eclipse.
Space 04
Do Rockets Need to Reach Escape Velocity? No. Here's Why
Escape velocity is 11.2 km/s, but no rocket needs it to leave Earth. It is a coasting speed, not a launch requirement. The real cost is energy and delta-v.
Space 05
How Fast Must a Space Station Spin for 1 g?
A station needs about 30/√r rpm for 1 g. Why small stations feel wrong: head-to-foot gradient, Coriolis, and the radius you really need. Worked numbers.
Space 06
Why We Only See One Side of the Moon (and It's 59%)
The Moon is tidally locked, spinning once per 27.3-day orbit. The torque that locked it, why we see 59% of it, and why it drifts 3.8 cm a year.