eight years later, he said yes ❤️ We’re both huge nerds and I wanted to do something unique for the proposal, so I designed this hexagonal mirror thingy. The mirrors are angled so that just before sunset on our 8th anniversary, it reflects the light from the setting sun onto the ground to spell “MARRY ME?”

As stars burn hotter and hotter, they go from looking red to orange to yellow to white to blue...

But why are there no green stars?👇 [1/4] Starlight looks basically like an ideal blackbody spectrum: a broad curve with the peak wavelength depending on the temperature.

However, our eyes see in a 3-dimensional color space by sampling the intensities of red, green, and blue light.

Alan Turing was born 108 years ago today. He was a computer scientist, a mathematician, a philosopher, and a victim of homophobia.

His work saved between 2-14 million lives in WWII.

Bigotry and intolerance drove him to suicide.

Here is some of what he gave to the world: [1/20] Historically, Turing is best known for his efforts in wartime codebreaking. During WWII, the Nazi forces used a machine called Enigma, which functioned as a cypher that changes settings on each keypress, to encrypt messages and communicate the location and time of air raids.

yesterday I learned something after tweeting this gif of a "supersonic" duck!

I assumed if the duck's wake made an angle α then its Mach number would be M=1/sin(α), like it is for air sonic booms. But for a small, slow-moving object on a water surface, this is not the case! 1/5

https://twitter.com/bencbartlett/status/1272921968585498624

This morning I got an email from Elie Raphaël pointing out an interesting result. (also mentioned by @A_J_Higgins!)

A small, slow object will emit a wake at an angle of 19.47° independent of speed! This was discovered by Lord Kelvin in 1887.

Here's a brief explanation why: 2/5

The English alphabet, according to physics:

A: surface area, generic linear operator, sometimes denotes unrealistic academic goals

a: acceleration, annihilation operator, sometimes a length

a,b,c,d: common coefficients

B: magnetic field, the grade you'll settle for

[1/9] 🅱️: magnetic field if you're into memes

C: integration constant

c: speed of light

D: differential operator, often the average grade in a class

d: by itself usually distance, next to another letter represents infinitesimal change (dx)

E: electric field, energy, expected value

What is the P≟NP problem and why would solving it revolutionize the world (and earn you $1M)? A Twitter thread:

Contents:
‣ Turing machines and time complexity
‣ Complexity classes
‣ P and NP
‣ Reducibility
‣ Impacts of P=NP
‣ Impacts of P≠NP
‣ Further reading

[1/n] P≟NP is probably the most important unsolved question in computer science. It asks whether problems which are easy to verify solutions to are also easy to solve.

To understand the question and why it is important, let's take a crash course in complexity theory... [2/n]

My new paper on photonic quantum programmable gate arrays is now on arXiv! 🍾⚛️🎉 We describe an architecture for a nanophotonic integrated circuit which can be reprogrammed to perform any quantum computation. arxiv.org/pdf/1910.10141… 1/ Photonic systems have many unique advantages for quantum information processing, but deterministic multi-photon gates are difficult to implement, and complex quantum circuits can be prohibitively large to do with free-space optics since processing is done along the photon path