Here, three implementations of Internet searches for time travelers are described, all seeking a prescient mention of information not previously available. The first search covered prescient content placed on the Internet, highlighted by a comprehensive search for specific terms in tweets on Twitter. The second search examined prescient inquiries submitted to a search engine, highlighted by a comprehensive search for specific search terms submitted to a popular astronomy web site. The third search involved a request for a direct Internet communication, either by email or tweet, pre-dating to the time of the inquiry. Given practical verifiability concerns, only time travelers from the future were investigated.
“At the moment, this hyperwafer can only exist for six milliseconds in a precisely calibrated field of magnetic energy, positrons, roasted garlic, and beta particles,” lab chief Dr. Paul Ellison told reporters at a press conference outside Nabisco’s $200 million seven-whole-grain accelerator.
The last line of the piece made me LOL for real. (thx, meg)
Using a large piece of spandex (representing spacetime) and some balls and marbles (representing masses), a high school science teacher explains how gravity works.
The bits about how the planets all orbit in the same direction and the demo of the Earth/Moon orbit are really neat. And you can stop watching around the 7-minute mark…the demos end around then.
Update:Here’s another video of a similar system with some slightly different demos.
Hans Bethe was a giant in the field of nuclear physics. He rubbed shoulders with Einstein, Bohr, and Pauli, was head of the Theoretical Division of the US atomic bomb project, and was awarded a Nobel Prize. In 1999, at the age of 93, Bethe gave a series of three lectures to the residents of his retirement community near Cornell University, where he had taught since 1935. Video of the lectures is available on the Cornell website.
In the first lecture, Bethe covers the development of the “old quantum theory”, covering the work of Max Planck and Niels Bohr. In the second and third lectures, he relates how modern quantum mechanics was developed, with a healthy amount of personal recollection along the way:
Professor Bethe offers personal anecdotes about many of the famous names commonly associated with quantum physics, including Bohr, Heisenberg, Born, Pauli, de Broglie, Schrödinger, and Dirac.
Without a doubt, this is the most high-power presentation ever made at a retirement home. (via @stevenstrogatz)
In theory, quantum computers can perform calculations far faster than their classical counterparts to solve incredibly complex problems. They do this by storing information in quantum bits, or qubits.
At any given moment, each of a classical computer’s bits can only be in an “on” or an “off” state. They exist inside conventional electronic circuits, which follow the 19th-century rules of classical physics. A qubit, on the other hand, can be created with an electron, or inside a superconducting loop. Obeying the counterintuitive logic of quantum mechanics, a qubit can act as if it’s “on” and “off” simultaneously. It can also become tightly linked to the state of its fellow qubits, a situation called entanglement. These are two of the unusual properties that enable quantum computers to test multiple solutions at the same time.
But in practice, a physical quantum computer is incredibly difficult to run. Entanglement is delicate, and very easily disrupted by outside influences. Add more qubits to increase the device’s calculating power, and it becomes more difficult to maintain entanglement.
Not to get all Malcolm Gladwell here, but it’s counterintuitive that hot water freezes faster than cold water. The phenomenon is called the Mpemba effect and until recently, no one could explain how it works. A group of researchers in Singapore think they’ve cracked the puzzle.
Now Xi and co say hydrogen bonds also explain the Mpemba effect. Their key idea is that hydrogen bonds bring water molecules into close contact and when this happens the natural repulsion between the molecules causes the covalent O-H bonds to stretch and store energy.
But as the liquid warms up, it forces the hydrogen bonds to stretch and the water molecules sit further apart. This allows the covalent molecules to shrink again and give up their energy. The important point is that this process in which the covalent bonds give up energy is equivalent to cooling.
In fact, the effect is additional to the conventional process of cooling. So warm water ought to cool faster than cold water, they say. And that’s exactly what is observed in the Mpemba effect.
NASA’s Solar Dynamics Observatory is getting some really amazing shots of the Sun, including this 200,000 mile-long solar eruption that left a huge canyon on the surface of the Sun:
Different wavelengths help capture different aspect of events in the corona. The red images shown in the movie help highlight plasma at temperatures of 90,000° F and are good for observing filaments as they form and erupt. The yellow images, showing temperatures at 1,000,000° F, are useful for observing material coursing along the sun’s magnetic field lines, seen in the movie as an arcade of loops across the area of the eruption. The browner images at the beginning of the movie show material at temperatures of 1,800,000° F, and it is here where the canyon of fire imagery is most obvious.
The level of detail shown is incredible. (via @DavidGrann)
It turns out that particles already known to us are not enough to account for the mass of the hot matter in which the sound waves must have propagated. Fully five sixths of the matter of the universe would have to be some kind of “dark matter,” which does not emit or absorb light. The existence of this much dark matter in the present universe had already been inferred from the fact that clusters of galaxies hold together gravitationally, despite the high random speeds of the galaxies in the clusters. So this is a great puzzle: What is the dark matter? Theories abound, and attempts are underway to catch ambient dark matter particles or remnants of their annihilation in detectors on Earth or to create dark matter in accelerators. But so far dark matter has not been found, and no one knows what it is.
Google’s got themselves a quantum computer (they’re sharing it with NASA) and they made a little video about it:
I’m sure that Hartmut is a smart guy and all, but he’s got a promising career as an Arnold Schwarzenegger impersonator hanging out there if the whole Google thing doesn’t work out.
Light (aka electromagnetic radiation) is responsible for most of what we know about the universe. By measuring photons of various frequencies in different ways — “the careful collection of ancient light” — we’ve painted a picture of our endless living space. But light isn’t perfect. It can bend, scatter, and be blocked. Changes in gravity are more difficult to detect, but new instruments may allow scientists to construct a different map of the universe and its beginnings.
LIGO works by shooting laser beams down two perpendicular arms and measuring the difference in length between them-a strategy known as laser interferometry. If a sufficiently large gravitational wave comes by, it will change the relative length of the arms, pushing and pulling them back and forth. In essence, LIGO is a celestial earpiece, a giant microphone that listens for the faint symphony of the hidden cosmos.
Like many exotic physical phenomena, gravitational waves originated as theoretical concepts, the products of equations, not sensory experience. Albert Einstein was the first to realize that his general theory of relativity predicted the existence of gravitational waves. He understood that some objects are so massive and so fast moving that they wrench the fabric of spacetime itself, sending tiny swells across it.
How tiny? So tiny that Einstein thought they would never be observed. But in 1974 two astronomers, Russell Hulse and Joseph Taylor, inferred their existence with an ingenious experiment, a close study of an astronomical object called a binary pulsar [see “Gravitational Waves from an Orbiting Pulsar,” by J. M. Weisberg et al.; Scientific American, October 1981]. Pulsars are the spinning, flashing cores of long-exploded stars. They spin and flash with astonishing regularity, a quality that endears them to astronomers, who use them as cosmic clocks. In a binary pulsar system, a pulsar and another object (in this case, an ultradense neutron star) orbit each other. Hulse and Taylor realized that if Einstein had relativity right, the spiraling pair would produce gravitational waves that would drain orbital energy from the system, tightening the orbit and speeding it up. The two astronomers plotted out the pulsar’s probable path and then watched it for years to see if the tightening orbit showed up in the data. The tightening not only showed up, it matched Hulse and Taylor’s predictions perfectly, falling so cleanly on the graph and vindicating Einstein so utterly that in 1993 the two were awarded the Nobel Prize in Physics.
Friday morning is as good a time as any to revisit what I consider one of the quintessential Kottke.org post(s), The case of the plane and conveyor belt. Essentially, will an airplane take off on a treadmill. Prompted by a question on The Straight Dope, the post, now over 7 years old, has everything you need for a Kottke.org post: airplanes, physics, a waffle, and careful consideration of the facts. The question was addressed again a few days later to definitively and succinctly put the argument to rest.
Now that I’ve closed the comments on the question of the airplane and the conveyor belt, I’m still getting emails calling me an idiot for thinking that the plane will take off. Having believed that after first hearing the question and formulating several reasons reinforcing my belief, I can sympathize with that POV, but that doesn’t change the fact that I was initially wrong and that if you believe the plane won’t take off, you’re wrong too.
I had no idea that’s how rubber bands worked. Once again, Feynman takes something that seems pretty simple and makes it both simpler and vividly complex.
Nearly fifty years have passed since Richard Feynman taught the introductory physics course at Caltech that gave rise to these three volumes, The Feynman Lectures on Physics. In those fifty years our understanding of the physical world has changed greatly, but The Feynman Lectures on Physics has endured. Feynman’s lectures are as powerful today as when first published, thanks to Feynman’s unique physics insights and pedagogy. They have been studied worldwide by novices and mature physicists alike; they have been translated into at least a dozen languages with more than 1.5 millions copies printed in the English language alone. Perhaps no other set of physics books has had such wide impact, for so long.
I took a Greek and Roman literature class in college. Among the texts we studied was Lucretius’ On The Nature of Things. Shamefully, about the only thing I remembered from it was that the poem was an early articulation of the concept of atoms (see also Democritus). Impressive, chatting about atoms in 50 BCE. But reading Stephen Greenblatt’s The Swerve has reminded me what an impressive and prescient document it is, quite apart from its beauty as a poem. In chapter eight of his book, Greenblatt summarizes the main points of Lucretius’ poem:
Everything is made of invisible particles.
The elementary particles of matter — “the seeds of things” — are eternal.
The elementary particles are infinite in number but limited in shape and size.
All particles are in motion in an infinite void.
The universe has no creator or designer.
Everything comes into being as a result of a swerve.
[Ok, the swerve deserves a bit of explanation. Here’s Greenblatt:
If all the individual particles, in their infinite numbers, fell through the void in straight lines, pulled down by their own weight like raindrops, nothing would ever exist. But the particles do no move lockstep in a preordained single direction. Instead, “at absolutely unpredictable time and places they deflect slightly from their straight course, to a degree that could be described as no more than a shift of movement.” The position of the elementary particles is thus indeterminate.
I can’t help but think of quantum mechanics here. Anyway, back to the list.]
The swerve is the source of free will.
Nature ceaselessly experiments.
The universe was not created for or about humans.
Humans are not unique.
Human society began not in a Golden Age of tranquility and plenty, but in a primitive battle for survival.
The soul dies.
There is no afterlife.
Death is nothing to us.
All organized religions are superstitious delusions.
Religions are invariably cruel.
There are no angels, demons, or ghosts.
The highest goal of human life is the enhancement of pleasure and the reduction of pain.
The greatest obstacle to pleasure is not pain; it is delusion.
Understanding the nature of things generates deep wonder.
The seeds of atomic theory, quantum mechanics, evolution, agnosticism, atheism…they’re all right there, in a poem written by a man who died more than 2000 years ago.
If you’re at all interested in the Pioneer Anomaly (and you really should be, it’s fascinating), The Pioneer Detectives ebook by Konstantin Kakaes looks interesting.
Explore one of the greatest scientific mysteries of our time, the Pioneer Anomaly: in the 1980s, NASA scientists detected an unknown force acting on the spacecraft Pioneer 10, the first man-made object to journey through the asteroid belt and study Jupiter, eventually leaving the solar system. No one seemed able to agree on a cause. (Dark matter? Tensor-vector-scalar gravity? Collisions with gravitons?) What did seem clear to those who became obsessed with it was that the Pioneer Anomaly had the potential to upend Einstein and Newton — to change everything we know about the universe.
Kakaes was a science writer for The Economist and studied physics at Harvard, so this topic seems right up his alley. Available for $2.99 for the Kindle and for iBooks on iOS.
On January 15, 1919 in Boston’s North End, a storage container holding around 2.3 million gallons of molasses ruptured, sending a 8-15 ft. wave of molasses shooting out into the streets at 35 mph. Twenty-one people died, many more were injured, and the property damage was severe. In an article in Scientific American, Ferris Jabr explains the science of the molasses flood, including why it was so deadly and destructive.
A wave of molasses does not behave like a wave of water. Molasses is a non-Newtonian fluid, which means that its viscosity depends on the forces applied to it, as measured by shear rate. Consider non-Newtonian fluids such as toothpaste, ketchup and whipped cream. In a stationary bottle, these fluids are thick and goopy and do not shift much if you tilt the container this way and that. When you squeeze or smack the bottle, however, applying stress and increasing the shear rate, the fluids suddenly flow. Because of this physical property, a wave of molasses is even more devastating than a typical tsunami. In 1919 the dense wall of syrup surging from its collapsed tank initially moved fast enough to sweep people up and demolish buildings, only to settle into a more gelatinous state that kept people trapped.
This could just be a Boston urban legend, but it’s said that on hot days in the North End, the sweet smell of molasses can be detected wafting through the air.
Pitch is an extremely viscous substance, about 2 million times more viscous than honey. Drops take 7-13 years to form and less than a second to fall. A similar experiment has been running at University of Queensland in Brisbane, Australia since 1927…their next drop is expected to fall sometime later this year.
Turning the Sun into a giant radio telescope through gravitational lensing will take some work, but it is possible.
An Italian space scientist, Claudio Maccone, believes that gravitational lensing could be used for something even more extraordinary: searching for radio signals from alien civilizations. Maccone wants to use the sun as a gravitational lens to make an extraordinarily sensitive radio telescope. He did not invent the idea, which he calls FOCAL, but he has studied it more deeply than anyone else. A radio telescope at a gravitational focal point of the sun would be incredibly sensitive. (Unlike an optical lens, a gravitational lens actually has many focal points that lie along a straight line, called a focal line; imagine a line running through an observer, the center of the lens, and the target.) For one particular frequency that has been proposed as a channel for interstellar communication, a telescope would amplify the signal by a factor of 1.3 quadrillion.
The center of the Sun is extremely dense, and a photon can only travel a tiny distance before running into another hydrogen nucleus. It gets absorbed by that nucleus and the re-emitted in a random direction. If that direction is back towards the center of the Sun, the photon has lost ground! It will get re-absorbed, and then re-emitted, over and over, trillions of times.
This is from 1997, so that figure might have been revised a bit (anyone have updated numbers?) but still, that’s incredible. (via hacker news)
Damn! Watch this railroad tanker car instantly implode:
I couldn’t find too much information on the source of this clip, but it appears to be part of a safety training video on the perils of improperly steam cleaning tanker cars. In the clip, the tanker car is filled with steam and the safety valves are disabled. The steam cools, then condenses, the pressure inside drops, and the pressure difference is big enough to crumple that huge railcar like a napkin.
Update: See also “sun kink”, when railroad tracks buckle in intense heat:
Normally when someone says they’ve thought up a theoretically possible perpetual motion scheme, you roll your eyes and pass the dutchie to the left hand side. But when that someone is a Nobel laureate in physics, is not generally off his rocker, and has published his idea in a prestigious peer-reviewed journal, people pay attention. Frank Wilczek believes he’s invented something called time crystals.
In February 2012, the Nobel Prize-winning physicist Frank Wilczek decided to go public with a strange and, he worried, somewhat embarrassing idea. Impossible as it seemed, Wilczek had developed an apparent proof of “time crystals” — physical structures that move in a repeating pattern, like minute hands rounding clocks, without expending energy or ever winding down. Unlike clocks or any other known objects, time crystals derive their movement not from stored energy but from a break in the symmetry of time, enabling a special form of perpetual motion.
“Most research in physics is continuations of things that have gone before,” said Wilczek, a professor at the Massachusetts Institute of Technology. This, he said, was “kind of outside the box.”
An effort to prove or disprove Wilczek’s theory is underway…let’s hope it holds up to scientific scrutiny better than Time Cube. (via digg)
The other day I posted a video about how differential gears work to help cars go smoothly around curves. Trains don’t have differential gears, so how do they manage to go around curves without slipping or skidding? Richard Feynman explains:
Ha, it looks like I’ve posted this one before as well. Can never get enough Feynman. (thx, kerry)
Well, this is interesting. Graphene is a substance discovered relatively recently that has a number of unusual properties. In 2004, physicists at the University of Manchester and the Institute for Microelectronics Technology in Russia used ordinary scotch tape to isolate single-layer sheets of graphene. Once isolated, the sheets could be tested for the unusual properties I mentioned. The 2010 Nobel Prize in Physics was awarded for this work.
In 2012, a group of researchers at UCLA discovered they could make single-layer sheets of graphene by coating a DVD with graphite oxide and then “playing” the disc in a plain old DVD drive. And then in a happy accident, they found that graphene has unusually high supercapacitance properties, which could mean that graphene could be used, for example, as a mobile phone battery that lasts all day, charges in a few seconds, and can be thrown into a compost bin after use.
Paul Frampton is a 69-year-old theoretical particle physicist who has co-authored papers with Nobel laureates. In late 2011, the absentminded professor met a Czech bikini model online. Over email and Yahoo chat, they became romantically involved and she sent him a plane ticket to come meet her at a photo shoot in Bolivia. Then she asked him to bring a bag of hers with him on his flight.
While in Bolivia, Frampton corresponded with an old friend, John Dixon, a physicist and lawyer who lives in Ontario. When Frampton explained what he was up to, Dixon became alarmed. His warnings to Frampton were unequivocal, Dixon told me not long ago, still clearly upset: “I said: ‘Well, inside that suitcase sewn into the lining will be cocaine. You’re in big trouble.’ Paul said, ‘I’ll be careful, I’ll make sure there isn’t cocaine in there and if there is, I’ll ask them to remove it.’ I thought they were probably going to kidnap him and torture him to get his money. I didn’t know he didn’t have money. I said, ‘Well, you’re going to be killed, Paul, so whom should I contact when you disappear?’ And he said, ‘You can contact my brother and my former wife.’ ” Frampton later told me that he shrugged off Dixon’s warnings about drugs as melodramatic, adding that he rarely pays attention to the opinions of others.
On the evening of Jan. 20, nine days after he arrived in Bolivia, a man Frampton describes as Hispanic but whom he didn’t get a good look at handed him a bag out on the dark street in front of his hotel. Frampton was expecting to be given an Hermès or a Louis Vuitton, but the bag was an utterly commonplace black cloth suitcase with wheels. Once he was back in his room, he opened it. It was empty. He wrote to Milani, asking why this particular suitcase was so important. She told him it had “sentimental value.” The next morning, he filled it with his dirty laundry and headed to the airport.
Unfortunately, [the X-Plane simulator] is not capable of simulating the hellish environment near the surface of Venus. But physics calculations give us an idea of what flight there would be like. The upshot is: Your plane would fly pretty well, except it would be on fire the whole time, and then it would stop flying, and then stop being a plane.
The timeline of the far future artice is far from the longest page on Wikipedia, but it might take you several hours to get through because it contains so many enticing detours. What’s Pangaea Ultima? Oooh, Roche limit! The Degenerate Era, Poincaré recurrence time, the Big Rip scenario, the cosmic light horizon, the list goes on and on. And the article itself is a trove of fascinating facts and eye-popping phrases. Here are a few of my favorites. (Keep in mind that the universe is only 13.75 billion years old. Unless we’re living in a computer simulation.)
50,000 years: “Niagara Falls erodes away the remaining 32 km to Lake Erie and ceases to exist.”
1 million years: “Highest estimated time until the red supergiant star Betelgeuse explodes in a supernova. The explosion is expected to be easily visible in daylight.”
1.4 million years: “The star Gliese 710 passes as close as 1.1 light years to the Sun before moving away. This may gravitationally perturb members of the Oort cloud; a halo of icy bodies orbiting at the edge of the Solar System. As a consequence, the likelihood of a cometary impact in the inner Solar System will increase.”
230 million years: “Beyond this time, the orbits of the planets become impossible to predict.”
800 million years: “Carbon dioxide levels fall to the point at which C4 photosynthesis is no longer possible. Multicellular life dies out.”
4 billion years: “Median point by which the Andromeda Galaxy will have collided with the Milky Way, which will thereafter merge to form a galaxy dubbed ‘Milkomeda’.”
7.9 billion years: “The Sun reaches the tip of the red giant branch, achieving its maximum radius of 256 times the present day value. In the process, Mercury, Venus and possibly Earth are destroyed. During these times, it is possible that Saturn’s moon Titan could achieve surface temperatures necessary to support life.”
100 billion years: “The Universe’s expansion causes all galaxies beyond the Milky Way’s Local Group to disappear beyond the cosmic light horizon, removing them from the observable universe.”
1 trillion years: “The universe’s expansion, assuming a constant dark energy density, multiplies the wavelength of the cosmic microwave background by 10^29, exceeding the scale of the cosmic light horizon and rendering its evidence of the Big Bang undetectable.”
1 quadrillion years: “Estimated time until stellar close encounters detach all planets in the Solar System from their orbits. By this point, the Sun will have cooled to five degrees above absolute zero.”
10^65 years: “Assuming that protons do not decay, estimated time for rigid objects like rocks to rearrange their atoms and molecules via quantum tunneling. On this timescale all matter is liquid.”
10^10^56 years: “Estimated time for random quantum fluctuations to generate a new Big Bang, according to Caroll and Chen.”
Read the whole thing, it’s worth the effort. (via @daveg)
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