Physics 01
Is Warp Drive Possible? The Alcubierre Energy Bill
Is warp drive possible? Alcubierre's 1994 metric is valid relativity, but it needs negative energy. We compute how much and check the newer claims.
Physics
Physics 02
How Does LIGO Detect Gravitational Waves? The Real Numbers
LIGO times laser light in two 4 km arms. GW150914 shifted their difference by 4×10⁻¹⁸ m, 1/420 of a proton. Optics, chirp and the stretched-light puzzle.
Physics 03
How Far Is the Horizon? Formula, Refraction, Examples
At 1.7 m eye height the sea horizon is 4.7 km away, about 5 km with refraction. The formula, how far you can see tall objects, and the 8 inches per mile error.
Physics 04
What Causes the Green Flash at Sunset? The Numbers
Every sunset has a green rim, but it is 4 to 8 times too thin to see. We compute the refraction and dispersion, and show why mirages make the flash visible.
Physics 05
Could a Lightsaber Exist? The Physics, With Numbers
Could a lightsaber exist? We compute the power to cut a blast door, why laser beams pass through each other, and why no magnet can hold a plasma blade.
Physics 06
Could the Dune Ornithopter Fly? Hover Power, Calculated
Could the Dune ornithopter fly? Momentum theory says its huge wings need less hover power than a helicopter. The real problems are wing mass and flapping.