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kottke.org posts about physics

An explainer video from 1923 about Einstein’s theory of relativity

posted by Jason Kottke   May 29, 2018

In 1923, Inkwell Studios1 released a 20-minute animated explanation of Albert Einstein’s theory of relativity, perhaps one of the very first scientific explainer videos ever made. Films were still silent in those days and the public’s scientific understanding limited (the discovery of Pluto was 7 years in the future, and penicillin 5 years) so the film is almost excruciatingly slow by today’s standards, but if you squint hard enough, you can see the great-grandparent to YouTube channels like Kurzgesagt, Nerdwriter, TED Ed, minutephysics, and the 119,000+ videos on YouTube returned for a “einstein relativity explained” search. (via open culture)

  1. Inkwell later became Fleischer Studios, which made cartoons like Betty Boop, Popeye, and the first animated Superman series. They also introduced the bouncing ball as a technique for singing along to on-screen lyrics.

Cities flowing like liquids or organized like crystals

posted by Patrick Tanguay   Apr 30, 2018

File this story at Citylab adjacent to concepts like complexity, scale, and fractals. It turns out—according to this research paper anyway—that cities’ heat islands function differently depending on the “texture” of the city itself.

[S]cientists know that the density of buildings, the absorption of light by those buildings, and the relative lack of vegetation in cities are major contributors to the urban heat island effect. It’s why cities like Chicago are hoping to find relief through green roofs and reflective construction materials, or through planting more trees and banning cars. In a more radical move, Los Angeles even began painting their roads white as part of Mayor Eric Garcetti’s effort to bring down the city’s temperature by just under 2 degrees over the next 20 years. […]

The difference is even starker at night: even as the temperature cools, the release of heat absorbed during the day by asphalt and densely packed buildings can make the downtown area some 20 degrees warmer in some cities.

Street Grids May Make Cities Hotter

Roland Pellenq, a senior research scientist at MIT’s Concrete Sustainability Hub, looked at city grids and the relative positions of buildings, to see if patterns emerge.

Indeed, the fingerprints of cities like Boston and Los Angeles mirror the disorderly atomic structure of liquids and glass, while the likes of Chicago and New York City, with their streets and avenues perpendicular to one another, exhibit a more orderly configuration found in crystals.

Using formulas borrowed from physics, originally developed to measure atomic interaction in condensed materials, they found that more tightly packed cities have more intense heat island effects but also:

[T]hat cities with more rigid grid-like street patterns (that is, a higher local order) tended to display a higher temperature difference between their urban and rural areas. This has to do with air flow, said Pellenq. In disorganized cities, the air tends to flow uniformly with little or no interruption. But the perpendicular streets of Chicago and the like often trap heat by disrupting that airflow.

Fascinating.

How to harvest nearly infinite energy from a spinning black hole

posted by Jason Kottke   Apr 23, 2018

Well, this is a thing I didn’t know about black holes before watching this video. Because some black holes spin, it’s possible to harvest massive amounts of energy from them, even when all other energy sources in the far far future are gone. This process was first proposed by Roger Penrose in a 1971 paper.

The Penrose process (also called Penrose mechanism) is a process theorised by Roger Penrose wherein energy can be extracted from a rotating black hole. That extraction is made possible because the rotational energy of the black hole is located not inside the event horizon of the black hole, but on the outside of it in a region of the Kerr spacetime called the ergosphere, a region in which a particle is necessarily propelled in locomotive concurrence with the rotating spacetime. All objects in the ergosphere become dragged by a rotating spacetime. In the process, a lump of matter enters into the ergosphere of the black hole, and once it enters the ergosphere, it is forcibly split into two parts. For example, the matter might be made of two parts that separate by firing an explosive or rocket which pushes its halves apart. The momentum of the two pieces of matter when they separate can be arranged so that one piece escapes from the black hole (it “escapes to infinity”), whilst the other falls past the event horizon into the black hole. With careful arrangement, the escaping piece of matter can be made to have greater mass-energy than the original piece of matter, and the infalling piece has negative mass-energy.

This same effect can also be used in conjunction with a massive mirror to superradiate electromagnetic energy: you shoot light into a spinning black hole surrounded by mirrors, the light is repeatedly sped up by the ergosphere as it bounces off the mirror, and then you harvest the super-energetic light. After the significant startup costs, it’s basically an infinite source of free energy.

Physics giant Stephen Hawking dead at age 76

posted by Jason Kottke   Mar 14, 2018

Lego Stephen Hawking

Stephen Hawking, who uncovered the mysteries of black holes and with A Brief History of Time did more than anyone to popularize science since the late Carl Sagan, has died at his home in Cambridge at age 76. From an obituary in The Guardian:

Hawking once estimated he worked only 1,000 hours during his three undergraduate years at Oxford. In his finals, he came borderline between a first- and second-class degree. Convinced that he was seen as a difficult student, he told his viva examiners that if they gave him a first he would move to Cambridge to pursue his PhD. Award a second and he threatened to stay. They opted for a first.

Those who live in the shadow of death are often those who live most. For Hawking, the early diagnosis of his terminal disease, and witnessing the death from leukaemia of a boy he knew in hospital, ignited a fresh sense of purpose. “Although there was a cloud hanging over my future, I found, to my surprise, that I was enjoying life in the present more than before. I began to make progress with my research,” he once said. Embarking on his career in earnest, he declared: “My goal is simple. It is a complete understanding of the universe, why it is as it is and why it exists at all.”

From Dennis Overbye’s obit in the NY Times:

He went on to become his generation’s leader in exploring gravity and the properties of black holes, the bottomless gravitational pits so deep and dense that not even light can escape them.

That work led to a turning point in modern physics, playing itself out in the closing months of 1973 on the walls of his brain when Dr. Hawking set out to apply quantum theory, the weird laws that govern subatomic reality, to black holes. In a long and daunting calculation, Dr. Hawking discovered to his befuddlement that black holes — those mythological avatars of cosmic doom — were not really black at all. In fact, he found, they would eventually fizzle, leaking radiation and particles, and finally explode and disappear over the eons.

Nobody, including Dr. Hawking, believed it at first — that particles could be coming out of a black hole. “I wasn’t looking for them at all,” he recalled in an interview in 1978. “I merely tripped over them. I was rather annoyed.”

That calculation, in a thesis published in 1974 in the journal Nature under the title “Black Hole Explosions?,” is hailed by scientists as the first great landmark in the struggle to find a single theory of nature — to connect gravity and quantum mechanics, those warring descriptions of the large and the small, to explain a universe that seems stranger than anybody had thought.

The discovery of Hawking radiation, as it is known, turned black holes upside down. It transformed them from destroyers to creators — or at least to recyclers — and wrenched the dream of a final theory in a strange, new direction.

“You can ask what will happen to someone who jumps into a black hole,” Dr. Hawking said in an interview in 1978. “I certainly don’t think he will survive it.

“On the other hand,” he added, “if we send someone off to jump into a black hole, neither he nor his constituent atoms will come back, but his mass energy will come back. Maybe that applies to the whole universe.”

Dennis W. Sciama, a cosmologist and Dr. Hawking’s thesis adviser at Cambridge, called Hawking’s thesis in Nature “the most beautiful paper in the history of physics.”

Roger Penrose, the eminent mathematician and physicist who collaborated with Hawking on discoveries related to black holes and the genesis of the universe, wrote a lengthy scientific obituary for Hawking in The Guardian.

Following his work in this area, Hawking established a number of important results about black holes, such as an argument for its event horizon (its bounding surface) having to have the topology of a sphere. In collaboration with Carter and James Bardeen, in work published in 1973, he established some remarkable analogies between the behaviour of black holes and the basic laws of thermodynamics, where the horizon’s surface area and its surface gravity were shown to be analogous, respectively, to the thermodynamic quantities of entropy and temperature. It would be fair to say that in his highly active period leading up to this work, Hawking’s research in classical general relativity was the best anywhere in the world at that time.

And then there was that time Hawking threw a party for time travellers but didn’t advertise it until after the party was over (to ensure only visitors from the future would show up).

Tonight is perhaps a good night to watch Errol Morris’ superb documentary on Hawking (with a wonderful Philip Glass soundtrack) or build a version of Hawking out of Lego.

Why speeding is so dangerous

posted by Jason Kottke   Feb 13, 2018

Let’s say you’re doing 100 mph in a car and suddenly a downed tree, stopped car, or person appears in the road up ahead and you need to slam on the brakes. How much more dangerous is that situation than when you’re doing 70 mph? Your intuition might tell you that 70 mph is only 30% less than 100 mph. But as this video shows, the important factor in stopping a car (or what happens to the car when it collides with something else) is not speed but energy, which increases at the square of speed. In other words, going from 70 mph to 100 mph more than doubles your energy…and going from 55 to 100 more than triples it. (thx, david)

Physics lessons using simple homemade marble tracks

posted by Jason Kottke   Nov 15, 2017

Bruce Yeany teaches physical science to 8th graders in Annville, PA and he is very enthusiastic about it. On his popular Homemade Science YouTube channel, Yeany highlights all sorts of physics experiments and demonstrations without using any special equipment. In one of his latest videos, he shares a bunch of marble tracks that he’s built to demonstrate motion and momentum.

The “identical track race” starting at 1:43 might blow your noodle a little bit unless you’re familiar with Galileo’s pendulum research. (via digg)

How to make an Extremely Large Telescope

posted by Jason Kottke   Nov 09, 2017

The Giant Magellan Telescope, currently under construction at the University of Arizona’s Mirror Lab, will be one of the first of a new class of telescopes called Extremely Large Telescopes. The process involved in fashioning the telescope’s seven massive mirrors is fascinating. This is one of those articles littered with mind-boggling statements at every turn. Such as:

“We want the telescope to be limited by fundamental physics — the wavelength of light and the diameter of the mirror — not the irregularities on the mirror’s surface,” says optical scientist Buddy Martin, who oversees the lab’s grinding and polishing operations. By “irregularities,” he’s talking about defects bigger than 20 nanometers — about the size of a small virus. But when the mirror comes out of the mold, its imperfections can measure a millimeter or more.

Precision of 20 nanometers on something more than 27 feet in diameter and weighing 17 tons? That’s almost unbelievable. In this video, Dr. Wendy Freedman, former chair of the board of directors for the GMT project, puts it this way:

The surface of this mirror is so smooth that if we took this 27-foot mirror and then spread it out, from coast-to-coast in the United States, east to west coast, the height of the tallest mountain on that mirror would be about 1/2 an inch. That’s how smooth this mirror is.

You need that level of smoothness if you’re going to achieve better vision than the Hubble:

With a resolving power 10 times that of the Hubble Space Telescope, the GMT is designed to capture and focus photons emanating from galaxies and black holes at the fringes of the universe, study the formation of stars and the worlds that orbit them, and search for traces of life in the atmospheres of habitable-zone planets.

The telescope has a price tag of $1 billion and should be operational within the the next five years in Chile.

A scientific simulation of Seveneves’ Moon disaster

posted by Jason Kottke   Oct 06, 2017

In the first line of Seveneves, Neal Stephenson lays out the event that the entire book’s action revolves around:

The moon blew up without warning and for no apparent reason.

Mild spoilers, but fairly quickly, scientists in the book figure out that this is a very bad thing that will cause humanity to become extinct unless drastic action is taken.

In the novel, one day the moon breaks up into 7 roughly equal-sized pieces. These pieces continue peacefully orbiting the Earth for a while, and eventually two pieces collide. This collision causes a piece to fragment, making future collisions more likely. The process repeats, at what Stephenson says is an exponential rate, until the Earth is under near-constant bombardment from meteorites, wiping out (nearly) all life on Earth.

Jason Cole wondered how plausible that scenario is and created a simulation to model it. Turns out Stephenson had his figures right.

If you blow air through sand, it behaves like a liquid

posted by Jason Kottke   Sep 21, 2017

If you take a bin full of sand and blow air up through the bottom of it, the sand behaves like a liquid. The bubbles were freaky enough when I watched this for the first time, but when the guy reached in to submerge the ball and it buoyantly popped right to the surface, my brain broke a little bit. This video from The Royal Institution explains what’s going on:

Note that this is a different effect than non-Newtonian liquids (which are also very cool).

Update: Mark Rober made a hot tub-sized fluidized air bed:

Black holes could delete the Universe

posted by Jason Kottke   Aug 25, 2017

In their latest video, Kurzgesagt takes a look at black holes, specifically how they deal with information. According to the currently accepted theories, one of the fundamental laws of the Universe is that information can never be lost, but black holes destroy information. This is the information paradox…so one or both of our theories must be wrong.

The paradox arose after Hawking showed, in 1974-1975, that black holes surrounded by quantum fields actually will radiate particles (“Hawking radiation”) and shrink in size (Figure 4), eventually evaporating completely. Compare with Figure 2, where the information about the two shells gets stuck inside the black hole. In Figure 4, the black hole is gone. Where did the information go? If it disappeared along with the black hole, that violates quantum theory.

Maybe the information came back out with the Hawking radiation? The problem is that the information in the black hole can’t get out. So the only way it can be in the Hawking radiation (naively) is if what is inside is copied. Having two copies of the information, one inside, one outside, also violates quantum theory.

So maybe black holes holographically encode their information on the surface?

How to predict total solar eclipses

posted by Jason Kottke   Aug 18, 2017

The Exploratorium in San Francisco has produced a great explainer video about the science of predicting total solar eclipses. Each eclipse belongs to a repeating series of eclipses called a Saros cycle that repeats every 18 years 11 days and 8 hours.

Saros 145

There are now 40 active Saros cycles and the August 2017 eclipse belongs to Saros 145, which produced its first total eclipse in June 1909 and will produce its last total eclipse in September 2648.

A tour of our solar system’s eclipses

posted by Jason Kottke   Aug 16, 2017

In a meditative video for the NY Times, Dennis Overbye takes us on a tour of eclipses that happen in our solar system and beyond.

On the 21st day of August, 2017, the moon will slide between the Earth and the sun, painting a swath of darkness across North America. The Great American Solar Eclipse. An exercise in cosmic geometry. A reminder that we live on one sphere among many, all moving to the laws of Kepler, Newton and Einstein.

Humans have many more vantage points from which to observe solar eclipses than when the last solar eclipse occurred in the US in 1979. I had no idea that the Mars rovers had caught partial solar eclipses on Mars…so cool. (via @jossfong)

A visual explanation of quantum mechanics

posted by Jason Kottke   Jul 27, 2017

From the ViaScience YouTube channel comes this 31-part video explainer of quantum mechanics. As the introduction video notes, there is a fair bit of math in these videos presented at a quick pace, but if you took calculus in high school or college and remember the notation, that (and the pause button) should get you through this pretty well. (via @jsonpaul, who calls the series “fantastic”)

Quantum entanglement effects observed over 100s of miles

posted by Jason Kottke   Jun 19, 2017

A group of Chinese scientists say they have demonstrated the effects of quantum entanglement over a distance of 1200 km (745 miles).

Entanglement involves putting objects in the peculiar limbo of quantum superposition, in which an object’s quantum properties occupy multiple states at once: like Schrodinger’s cat, dead and alive at the same time. Then those quantum states are shared among multiple objects. Physicists have entangled particles such as electrons and photons, as well as larger objects such as superconducting electric circuits.

Theoretically, even if entangled objects are separated, their precarious quantum states should remain linked until one of them is measured or disturbed. That measurement instantly determines the state of the other object, no matter how far away. The idea is so counterintuitive that Albert Einstein mocked it as “spooky action at a distance.”

What’s weird to me is that all the articles I read about this touted that this happened in space, that an ultra-secure communications network was possible, or that we could build a quantum computer in space. Instantaneous communication over a distance of hundreds of miles is barely mentioned. Right now, it takes about 42 minutes for a round-trip communication between the Earth and Mars (and ~84 minutes for Jupiter). What if, when humans decide to settle on Mars, we could send a trillion trillion quantum entangled particles along with the homesteaders that could then be used to communicate in real time with people on Earth? I mean, how amazing would that be?

Update: Well, the simple reason why these articles don’t mention instantaneous communication at distance is that you can’t do it, even with quantum entanglement.

This is one of the most confusing things about quantum physics: entanglement can be used to gain information about a component of a system when you know the full state and make a measurement of the other component(s), but not to create-and-send information from one part of an entangled system to the other. As clever of an idea as this is, Olivier, there’s still no faster-than-light communication.

(thx, everyone)

If you can’t explain something in simple terms, you don’t understand it

posted by Jason Kottke   Jun 15, 2017

Feynman Blackboard

In the early 1960s, Richard Feynman gave a series of undergraduate lectures that were collected into a book called the Feynman Lectures on Physics. Absent from the book was a lecture Feynman gave on planetary motion, but a later finding of the notes enabled David Goodstein, a colleague of Feynman’s, to write a book about it: Feynman’s Lost Lecture. From an excerpt of the book published in a 1996 issue of Caltech’s Engineering & Science magazine:

Feynman was a truly great teacher. He prided himself on being able to devise ways to explain even the most profound ideas to beginning students. Once, I said to him, “Dick, explain to me, so that I can understand it, why spin one-half particles obey Fermi-Dirac statistics.” Sizing up his audience perfectly, Feynman said, “I’ll prepare a freshman lecture on it.” But he came back a few days later to say, “I couldn’t do it. I couldn’t reduce it to the freshman level. That means we don’t really understand it.”

John Gruber writes the simple explanations are the goal at Apple as well:

Engineers are expected to be able to explain a complex technology or product in simple, easily-understood terms not because the executive needs it explained simply to understand it, but as proof that the engineer understands it completely.

Feynman was well known for simple explanations of scientific concepts that result a in deeper understanding of the subject matter: e.g. see Feynman explaining how fire is stored sunshine, rubber bands, how trains go around curves, and magnets. Critically, he’s also not shy about admitting when he doesn’t understand something…or, alternately, when scientists as a group don’t understand something. There’s the spin anecdote above and of his explanation of magnets, he says:

I really can’t do a good job, any job, of explaining magnetic force in terms of something else you’re more familiar with, because I don’t understand it in terms of anything else you’re more familiar with.

Feynman was also quoted as saying:

I think I can safely say that nobody understands quantum mechanics.

Pretty interesting thing to hear from a guy who won a Nobel Prize for explaining quantum mechanics better than anyone ever had before. Even when he died in 1988 at the end of a long and fruitful careeer, a note at the top of his blackboard read:

What I cannot create, I do not understand.

The absurd precision involved in detecting gravitational waves

posted by Jason Kottke   Apr 27, 2017

Back in September 2015, the LIGO experiment detected gravitational waves formed 1.3 billion years ago when two black holes merged into one. The physics is pretty straightforward but to get the measurement, scientists had to build one of the most sensitive machines ever built. How sensitive? To get an accurate result, they needed to measure a distance of 4km with an accuracy of 1/10000th the width of a proton. This video from Veritasium looks at how the scientists and engineers accomplished such an amazing feat.

What will the night sky look like in 5 million years?

posted by Jason Kottke   Apr 13, 2017

Based on the motions of the 2 million stars observed by ESA’s Gaia mission over the past two years, scientists created this simulated animation of how the view of the Milky Way in the night sky will evolve over the next 5 million years.

The shape of the Orion constellation can be spotted towards the right edge of the frame, just below the Galactic Plane, at the beginning of the video. As the sequence proceeds, the familiar shape of this constellation (and others) evolves into a new pattern. Two stellar clusters — groups of stars that were born together and consequently move together — can be seen towards the left edge of the frame: these are the alpha Persei (Per OB3) and Pleiades open clusters.

Stars seem to move with a wide range of velocities in this video, with stars in the Galactic Plane moving quite slow and faster ones appearing over the entire frame. This is a perspective effect: most of the stars we see in the plane are much farther from us, and thus seem to be moving slower than the nearby stars, which are visible across the entire sky.

Well, how’s that for some perspective? (via blastr)

The Orion Nebula, our friendly neighborhood star factory

posted by Jason Kottke   Apr 03, 2017

Orion Nebula

Rolf Olsen recently took this amazing photo of the Orion Nebula using a home-built telescope.

The Orion Nebula is one of the most studied objects in the sky and also has a significant place in the history of astrophotography. In 1880 it was the first ever nebula to be photographed; Henry Draper used the newly invented dry plate process to acquire a 51-minute exposure of the nebula with an 11 inch telescope. Subsequently, in 1883, amateur astronomer Andrew Ainslie Common recorded several exposures up to 60 minutes long with a much larger 36-inch telescope, and showed for the first time that photography could reveal stars and details fainter than those visible to the human eye.

Thanks to Phil Plait for the link…he’s got much more to say about the image and the nebula here.

Also called M42 (the 42nd object in a catalog kept by comet hunter Charles Messier in the late 18th century), it is a sprawling star factory, a gas cloud where stars are born. It’s a couple of dozen light-years across, and sits well over a thousand light-years from Earth. That’s 10,000 trillion kilometers, and you can see it with your naked eye! It’s so bright because of a handful of extremely massive hot stars sit in its center. They blast out ultraviolet light that energizes the gas in the nebula, causing it to glow.

It’s actually a small section of a much larger dark cloud, what’s called a molecular cloud, that we cannot see directly. Stars were born near the edge of that cloud, not too deeply inside it, and when they switched on their fierce light and stellar winds blew a hole in the cloud, popping it like a bubble. The Orion Nebula is a cavity in the side of that cloud, carved by the newborn stars.

A full rotation of the Moon

posted by Jason Kottke   Mar 31, 2017

All but a few humans have seen no more than half of the Moon with their own eyes. For the rest of us stuck on Earth, we only get to see the side that always faces the Earth because the Earth & Moon are tidally locked; the Moon’s rotation about its axis and its orbit around the Earth take the same amount of time. But NASA’s LRO probe has taken high-resolution photos of all but 2% of the Moon’s surface, which have been stitched together into this video of the Moon’s full 360-degree rotation.

Recreating the Asteroids arcade game with a laser

posted by Jason Kottke   Mar 22, 2017

Watch as digital artist Seb Lee-Delisle recreates the old school video game Asteroids with a laser. But why use a laser? There’s actually a good explanation for this. In the olden days of arcade video games, the screens on most games were like Pac-Man or Donkey Kong…a typical CRT refreshed the entire screen line-by-line many times a second to form a pixelized scene. But with vector games like Tempest, Star Wars, and Asteroids, the electron beam was manipulated magnetically to draw the ships and rocks and enemies directly…and you get all these cool effects like phosphor trails and brighter objects where the beam lingers. When you play Asteroids on a contemporary computer or gaming system, all those artifacts are lost. But with a laser, you can emulate the original feel of the game much more closely.

You’re not going to want to because it’s 17 minutes long, but you should watch the whole video…it’s super nerdy and the explanations of how the various technologies work is worth your while (unless you’re already a laser expert). I loved the bit near the end where they slowed down the rate of the laser so you could see it drawing the game and then slowly sped it back up again, passing through the transition from seeing the individual movements of the laser to observing an entire seamless scene that our mind has stitched together. In his recent book Wonderland, Steven Johnson talks about this remarkable trick of the mind:

On some basic level, this property of the human eye is a defect. When we watch movies, our eyes are empirically failing to give an accurate report of what is happening in front of them. They are seeing something that isn’t there. Many technological innovations exploit the strengths that evolution has granted us: tools and utensils harness our manual dexterity and opposable thumbs; graphic interfaces draw on our powerful visual memory to navigate information space. But moving pictures take the opposite approach: they succeed precisely because our eyes fail.

This flaw was not inevitable. Human eyesight might have just as easily evolved to perceive a succession of still images as exactly that: the world’s fastest slide show. Or the eye might have just perceived them as a confusing blur. There is no evolutionary reason why the eye should create the illusion of movement at twelve frames per second; the ancestral environment where our visual systems evolved had no film projectors or LCD screens or thaumatropes. Persistence of vision is what Stephen Jay Gould famously called a spandrel — an accidental property that emerged as a consequence of other more direct adaptations. It is interesting to contemplate how the past two centuries would have played out had the human eye not possessed this strange defect. We might be living in a world with jet airplanes, atomic bombs, radio, satellites, and cell phones — but without television and movies. (Computers and computer networks would likely exist, but without some of the animated subtleties of modern graphical interfaces.) Imagine the twentieth century without propaganda films, Hollywood, sitcoms, the televised Nixon-Kennedy debate, the footage of civil rights protesters being fire-hosed, Citizen Kane, the Macintosh, James Dean, Happy Days, and The Sopranos. All those defining experiences exist, in part, because natural selection didn’t find it necessary to perceive still images accurately at rates above twelve frames a second — and because hundreds of inventors, tinkering with the prototypes of cinema over the centuries, were smart enough to take that imperfection and turn it into art.

A fictional flight above real Mars

posted by Jason Kottke   Mar 15, 2017

Using real images of Mars taken by the HiRISE camera on the Mars Reconnaissance Orbiter, Jan Fröjdman created a 3D-rendered flyover of several areas of the planet’s surface.

In this film I have chosen some locations and processed the images into panning video clips. There is a feeling that you are flying above Mars looking down watching interesting locations on the planet. And there are really great places on Mars! I would love to see images taken by a landscape photographer on Mars, especially from the polar regions. But I’m afraid I won’t see that kind of images during my lifetime.

It has really been time-consuming making these panning clips. In my 3D-process I have manually hand-picked reference points on the anaglyph image pairs. For this film I have chosen more than 33.000 reference points! It took me 3 months of calendar time working with the project every now and then.

Watch this in the highest def you can muster…gorgeous.

The time crystals concept is now reality

posted by Jason Kottke   Feb 07, 2017

Time Crystals

In 2012, physicist Frank Wilczek speculated that it would be possible to make a crystal whose lattice repeats in four dimensions, not just three.

Wilczek thought it might be possible to create a similar crystal-like structure in time, which is treated as a fourth dimension under relativity. Instead of regularly repeating rows of atoms, a time crystal would exhibit regularly repeating motion.

Many physicists were sceptical, arguing that a time crystal whose atoms could loop forever, with no need for extra energy, would be tantamount to a perpetual motion machine — forbidden by the laws of physics.

Now, a team at Berkeley have succeeded in making time crystals, publishing a method that two other teams have already successfully followed.

For Yao’s time crystal, an external force — like the pulse of a laser — flips the magnetic spin of one ion in a crystal, which then flips the spin of the next, and so forth, setting the system into a repeating pattern of periodic motion.

There are two critical factors. First, after the initial driver, it must be a closed system, unable to interact with and lose energy to the environment. Second, interactions between quantum particles are the driving force behind the time crystal’s stability. “It’s an emergent phenomenon,” says Yao. “It requires many particles and many spins to talk to each other and collectively synchronise.”

The leisurely pace of light speed

posted by Jason Kottke   Jan 25, 2017

In a 45-minute video called Riding Light, Alphonse Swinehart animates the journey outward from the Sun to Jupiter from the perspective of a photon of light. The video underscores just how slow light is in comparison to the vast distances it has to cover, even within our own solar system. Light takes 8.5 minutes to travel from the Sun to the Earth, almost 45 minutes to Jupiter, more than 4 years to the nearest star, 100,000 years to the center of our galaxy, 2.5 million years to the nearest large galaxy (Andromeda), and 32 billion years to reach the most remote galaxy ever observed.1 The music is by Steve Reich (Music for 18 Musicians), whose music can also seem sort of endless.

If you’re impatient, you can watch this 3-minute version, sped up by 15 times:

  1. This isn’t strictly true. As I understand it, a photon that just left the Sun will never reach that most remote galaxy.

LIGO’s gravitational wave data may contradict relativity

posted by Jason Kottke   Dec 12, 2016

Earlier this year, the LIGO experiment detected evidence of gravitational waves. Now the evidence shows that those waves may have echoes, which would contradict one of the tentpoles of modern physics, the general theory of relativity.

It was hailed as an elegant confirmation of Einstein’s general theory of relativity — but ironically the discovery of gravitational waves earlier this year could herald the first evidence that the theory breaks down at the edge of black holes. Physicists have analysed the publicly released data from the Laser Interferometer Gravitational-Wave Observatory (LIGO), and claim to have found “echoes” of the waves that seem to contradict general relativity’s predictions.

The echoes could yet disappear with more data. If they persist, the finding would be extraordinary. Physicists have predicted that Einstein’s hugely successful theory could break down in extreme scenarios, such as at the centre of black holes. The echoes would indicate the even more dramatic possibility that relativity fails at the black hole’s edge, far from its core.

If the echoes go away, then general relativity will have withstood a test of its power — previously, it wasn’t clear that physicists would be able to test their non-standard predictions.

Carl Sagan explains the fourth dimension

posted by Jason Kottke   Dec 06, 2016

From his seminal TV program Cosmos, Carl Sagan attempts to explain the fourth dimension of spacetime. The story starts with Edwin Abbott’s Flatland, but Sagan being Sagan, his explanation is especially lucid.

The Map of Physics

posted by Jason Kottke   Dec 01, 2016

In this video, physicist Dominic Walliman explains how all of the various disciplines of physics are related to each other by arranging them on a giant map. He starts with the three main areas — classical physics, quantum mechanics, and relativity — and then gets into the more specific subjects like optics, electromagnetism, and particle physics before venturing across The Chasm of Ignorance (dun dun DUN!) where things like string theory and dark matter dwell.

Posters of The Map of Physics are available.

NASA’s analysis of seemingly impossible engine: it works

posted by Jason Kottke   Nov 21, 2016

EM Drive NASA

NASA has published their highly anticipated and peer-reviewed analysis of the EM Drive and they’ve concluded the engine works despite appearing to violate Newton’s third law of motion.

In case you’ve missed the hype, the EM Drive, or Electromagnetic Drive, is a propulsion system first proposed by British inventor Roger Shawyer back in 1999.

Instead of using heavy, inefficient rocket fuel, it bounces microwaves back and forth inside a cone-shaped metal cavity to generate thrust.

According to Shawyer’s calculations, the EM Drive could be so efficient that it could power us to Mars in just 70 days.

But, there’s a not-small problem with the system. It defies Newton’s third law, which states that everything must have an equal and opposite reaction.

According to the law, for a system to produce thrust, it has to push something out the other way. The EM Drive doesn’t do this.

Yet in test after test it continues to work. Last year, NASA’s Eagleworks Laboratory team got their hands on an EM Drive to try to figure out once and for all what was going on.

There’s a lot of skepticism around this project, but NASA’s review is definitely a boost to the EM Drive’s credibility.

Update: Just to reiterate, even with this latest paper, there is still skepticism about the EM Drive.

In the end, we can’t conclude that this is a null result, nor can we excitedly say that it works. The sad truth is that this paper is not much better than the researchers’ last one, and it doesn’t actually have enough detail to let us fully evaluate the data. Nor does the paper have enough data to allow a conclusion in the absence of a model. And despite mention of a model in the paper, any model that exists is very well hidden.

Also a clue that the science isn’t quite there on this one yet: very few mainstream science outlets covered this. When the NY Times picks this up and gets prominent physicists on the record about the thruster’s promise, that’s when you’ll know something’s up. Until then, remain skeptical. (via @paudo)

The Most Efficient Way to Destroy the Universe

posted by Jason Kottke   Oct 24, 2016

Kurzgesagt shares a speculative bit of physics called vacuum decay that could very efficiently erase the entire Universe.

To understand vacuum decay, you need to consider the Higgs field that permeates our Universe. Like an electric field, the Higgs field varies in strength, based on its potential. Think of the potential as a track on which a ball is rolling. The higher it is on the track, the more energy the ball has.

The Higgs potential determines whether the Universe is in one of two states: a true vacuum, or a false vacuum. A true vacuum is the stable, lowest-energy state, like sitting still on a valley floor. A false vacuum is like being nestled in a divot in the valley wall — a little push could easily send you tumbling. A universe in a false vacuum state is called “metastable”, because it’s not actively decaying (rolling), but it’s not exactly stable either.

There are two problems with living in a metastable universe. One is that if you create a high enough energy event, you can, in theory, push a tiny region of the universe from the false vacuum into the true vacuum, creating a bubble of true vacuum that will then expand in all directions at the speed of light. Such a bubble would be lethal.

Such a process could already be underway, but don’t worry:

But even if one or multiple spheres of death have already started expanding, the Universe is so big they might not reach us for billions of years.

Scientists accidentally discover a process to turn CO2 into fuel

posted by Jason Kottke   Oct 19, 2016

Scientists at Oak Ridge National Laboratory have stumbled upon a process that uses “nanospikes” to turn carbon dioxide into ethanol, a common fuel.

This process has several advantages when compared to other methods of converting CO2 into fuel. The reaction uses common materials like copper and carbon, and it converts the CO2 into ethanol, which is already widely used as a fuel.

Perhaps most importantly, it works at room temperature, which means that it can be started and stopped easily and with little energy cost. This means that this conversion process could be used as temporary energy storage during a lull in renewable energy generation, smoothing out fluctuations in a renewable energy grid.

This sounds like a big deal…is it now possible to limit the effects of climate change by sinking carbon while also placing less dependence on fossil fuels? Here’s the Oak Ridge press release. That this news is almost a week old already and we haven’t heard more about it makes me a bit skeptical as to the true importance of it. (Of course, CRISPR is potentially a massive deal and we don’t hear about it nearly enough so…)

Update: A relevant series of tweets from Eric Hittinger on “why creating ethanol from CO2 cannot solve our energy or climate problems”. Wasn’t fully awake when I posted this apparently because, yeah, duh. (via @leejlh)

A well-designed reissue of Newton’s Principia

posted by Jason Kottke   Oct 18, 2016

Newton Principia

Small Spanish publisher Kronecker Wallis is doing a Kickstarter campaign to print a well-designed version of Isaac Newton’s Principia, one of the most important texts in science.

We have spent several months working on a desire. The desire to have a new edition of Isaac Newton’s Principia in our hands that is on a par with the importance of the text and of modern editorial design. To put it back on our shelves so that we can leaf through it from time to time and feel the pages beneath our fingers.

An opportunity has now arisen. Taking advantage of the fact that the original publication is to celebrate its 330th anniversary in 2017, we wish to republish it with an editorial design that pays attention to every last detail.

I am enjoying this trend of reviving old classics through the lens of modern design and packaging; see also the NYCTA Graphics Standards Manual, the NASA Graphics Standards Manual, and the Voyager Golden Record.