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What is a zero refractive index material?
I’m currently writing a textbook on Electromagnetic Waves for my graduate optics students. I was reading up on zero refractive index materials for a chapter section and thought it would be fu…
Topics /
Science & Space
The most popular blog posts about science & space on Hacker News. 160 posts.
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“Internet in space” will transform the satellite imagery industry
(First, Some Background)
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Symmetry in Chaos
The following is based upon systems of equations found in "Symmetry in Chaos, A Search for Pattern in Mathematics, Art, and Nature" (the second edition) by Michael Field and Martin Golubitsky. They ask the question whether there are aperiodic chaotic attractors that generate symmetric patterns? Can there be order…
64
The falling nutritional value of crops
The mineral content of wheat and rice is lower today than sixty years ago. Why is that and what does it mean for how we eat?
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A CD Spectrometer (2006)
A simple spectrometer can be built from a CD and a box. Cut a slit on one side of the box. Place the CD on the other side with about 60 degree angle. Look down into the openning on the box. The slit should not be too wide, otherwise the spectrum lines will be blurred. It should not be too narrow either, otherwise the…
66
Could we stop Yellowstone from erupting with a giant geothermal power plant?
It’s become fairly common knowledge that Yellowstone National Park, in addition to being incredibly beautiful, is sitting on top of an enormous supervolcano that catastrophically erupts every few hundred thousand years.
67
Feynman’s Maze-Running Story
Richard Feynman recounts an amazing anecdote about philosophy of science; we trace it to a forgotten University of Michigan research programme into ‘floor cues’.
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SpaceX's Texas Rocket Is Going to Cause a Lot More Damage Than Anyone Thinks
On Friday, the Federal Aviation Administration issued a license for SpaceX to launch the first orbital test of Starship, the largest rocket in human history, as soon as this Monday, April 17th.
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Carl Sagan's Rules for Bullshit-Busting and Critical Thinking
Necessary cognitive fortification against propaganda, pseudoscience, and general falsehood.
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Introduction to the Fourier transform for image processing (2001)
The definitons of the transform (to expansion coefficients) and the inverse transform are given below:
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Fusion Foolery
Great. The fusion hype is bad enough already. Now its resurgence is going to interrupt the series of posts I’m in the middle of publishing in order for this post to be “timely.”
73
How large is that number in the Law of Large Numbers?
All large numbers are large, but some are larger than others
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Maxar's Open Satellite Feed
Benchmarks & Tips for Big Data, Hadoop, AWS, Google Cloud, PostgreSQL, Spark, Python & More...
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Report on an Unidentified Space Station (1982)
By good luck we have been able to make an emergency landing on this uninhabited space station. There have been no casualties. We all count ourselves fortunate to have found safe haven at a moment when the expedition was clearly set on disaster.
76
Signal reflections in electronic circuits
What are "signal reflections", really? And do they matter in circuit design?
77
How many billions of transistors in an iPhone processor?
In about 10 years, Apple has multiplied by 19 the number of transistors in its mobile processors. It corresponds roughly to a steady rate of improvement of 34% per year on the number of transistors, or a doubling every 2.5 years. In real dollars, an iPhone has roughly a constant price: the price tag of … Continue…
78
The basics of decoupling capacitors
How to stabilize digital supply voltages - and why most of the online advice on this topic is suspect.
79
Reading Ancient Scrolls
This is an elaboration of my submission for the letter detection prize as part of the Vesuvius Challenge in June. It gets technical and esoteric but the first few paragraphs are of general interest…
80
How to slow down scientific progress, according to Leo Szilard
“Science would become something like a parlor game. There would be fashions. Those who followed the fashion would get grants”
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Does the world have enough lithium to move to electric vehicles?
The world has enough lithium, but we need to scale up production this decade.
82
Watching Paint Dry: The unexpectedly interesting story of car coatings
The unexpectedly interesting story of car coatings and what they tell us about the modern world
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Can solar and wind power Britain? An update of David MacKay's numbers
These technologies have developed a lot since 2008. Should we be any more optimistic about their potential to power Britain?
84
The crash of Air France flight 447 (2021)
The story of the infamous disappearance of an Airbus A330 over the Atlantic, and the fundamentally human mistakes which led to the tragedy.
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I measured the pollution from my gas stove
Here's what I learned putting air quality monitors all over my house.
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Passive Solar Water Desalination
I know we are supposed to be worried about the world supply of fresh water. I have been hearing that at least for the last 40 years, and the statistics are alarming. According to the Global Commission on the Economics of Water: "We are seeing the consequences not of freak events, nor of population growth
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Ultra Deep look at Messier 81 and 82
An ultra deep 393h look at the galaxy pair M81/M82 - Amateurs reveal full Ha stream for the first time
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Aspartame: Once More Unto the Breach
Like it or not, there’s a clear scientific consensus
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How to date a recording using background electrical noise
Three men were accused of selling firearms to South London gangs. At their 2012 trial in Croydon Crown Court, the prosecution played the jury a recording, taken undercover, of the trio allegedly arranging a sale. But the men’s lawyers claimed that the recording was a fake, and that the police had fabricated it by…
90
A mathematical formalization of dimensional analysis (2012)
Mathematicians study a variety of different mathematical structures, but perhaps the structures that are most commonly associated with mathematics are the number systems, such as the integers $late…