Bouncing baby bombs
This little guy is a newborn uncontrolled nuclear fisson reaction. You know, an atomic bomb.
This is from a NY Times photo slideshow of atomic bomb explosions. Check out the school bus sequence starting at slide #14.
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kottke.org posts about physics
When will the first Earth-like planet be discovered?
Using the properties of previously discovered exoplanets (that is, planets outside of our solar system) and their dates of discovery, Sam Arbesman and Greg Laughlin predict that the discovery of the first Earth-like exoplanet will likely occur in early May 2011.
Of course, it’s a bit more complicated than that, but here’s an overview of what we did. Using the properties of previously discovered exoplanets, we developed a simple metric of habitability for each planet that uses its mass and temperature to rate it on a scale of 0 to 1, where 1 is Earth-like, and 0 is so very not Earth-like. Plotting these values over time and taking the upper envelope yields a nice march towards habitability.
The authors don’t address this directly in their paper, but I wondered what the Moore’s Law for planetary discovery might be — e.g. every X years (or months?), the habitability of the most habitable planet discovered doubles. So I emailed Sam Arbesman and he said that his quick back of the envelope calculation would be “half a month or so”…which is an astounding pace.
The Grand Design
Stephen Hawking’s new book is out: The Grand Design, sequel to A Brief History of Time written with Leonard Mlodinow.
In The Grand Design we explain why, according to quantum theory, the cosmos does not have just a single existence, or history, but rather that every possible history of the universe exists simultaneously. We question the conventional concept of reality, posing instead a “model-dependent” theory of reality. We discuss how the laws of our particular universe are extraordinarily finely tuned so as to allow for our existence, and show why quantum theory predicts the multiverse—the idea that ours is just one of many universes that appeared spontaneously out of nothing, each with different laws of nature. And we assess M-Theory, an explanation of the laws governing the multiverse, and the only viable candidate for a complete “theory of everything.”
The physics of free kicks
Why are long free kicks suprisingly effective in soccer matches? Science explains!
For a well-struck soccer ball, the researchers estimate, one might expect a gentle arc followed by a sharp hook at about 50 meters — in rough agreement with the distance of Roberto Carlos’s free kick. In other words, if a soccer player has the strength to drive a ball halfway down the field with plenty of velocity and spin, he or she can expect to benefit from an unexpected curve late in the ball’s trajectory.
But really, this is just an excuse to show you Roberto Carlos’ amazing free kick against France in 1997:
Pure awesometown. But it might not be even be better than this one:
The speed of gravity
Newton said the speed of gravity is infinite but according to Einstein (and some nifty interstellar measurements), it most certainly is not.
But in general relativity, things are much more intricate, and incredibly interesting. First off, it isn’t mass, per se, that causes gravity. Rather, all forms of energy (including mass) affect the curvature of space. So for the Sun and the Earth, the incredibly large mass of the Sun dominates the curvature of space, and the Earth travels in an orbit along that curved space.
If you simply took the Sun away, space would go back to being flat, but it wouldn’t do so right away at every point. In fact, just like the surface of a pond when you drop something into it, it snaps back to being flat, and the disturbances send ripples outward!
Sun may affect radioactive decay rates
During a search for a radioactive isotope-based random number generator, researchers discovered that radioactive decay rates, previously thought to be constant, appear to be influenced by the activity of the Sun.
On Dec 13, 2006, the sun itself provided a crucial clue, when a solar flare sent a stream of particles and radiation toward Earth. Purdue nuclear engineer Jere Jenkins, while measuring the decay rate of manganese-54, a short-lived isotope used in medical diagnostics, noticed that the rate dropped slightly during the flare, a decrease that started about a day and a half before the flare.
If this apparent relationship between flares and decay rates proves true, it could lead to a method of predicting solar flares prior to their occurrence, which could help prevent damage to satellites and electric grids, as well as save the lives of astronauts in space.
The decay-rate aberrations that Jenkins noticed occurred during the middle of the night in Indiana — meaning that something produced by the sun had traveled all the way through the Earth to reach Jenkins’ detectors. What could the flare send forth that could have such an effect?
Jenkins and Fischbach guessed that the culprits in this bit of decay-rate mischief were probably solar neutrinos, the almost massless particles famous for flying at nearly the speed of light through the physical world — humans, rocks, oceans or planets — with virtually no interaction with anything.
Maybe the science part of 2012 wasn’t so far-fetched after all. (No, not really.)
Slow motion lightning strike
A lightning strike recorded at 9000 frames per second.
The action across time scales displayed in this video is amazing. One strike hovers in the frame almost the entire time while other hundreds of other strikes flicker in and out in single frames.
Are you there God particle? It’s me, Fermilab.
By further isolating where the Higgs boson isn’t, scientists are finally closing in on the discovery of the so-called God particle…or proving that it doesn’t exist at all.
Its mass — in the units preferred by physicists — is not in the range between 158 billion and 175 billion electron volts, according to a talk by Ben Kilminster of Fermilab at the International Conference on High Energy Physics in Paris.
Cancer-causing box springs?
Rates of breast cancer and melanoma in humans are on the rise and appear to favor the left side of the body. A suspected cause is that the box springs in our beds act as antennas to focus the EM radiation from FM radio and broadcast television directly into the left sides of our bodies. No, really:
Electromagnetic waves resonate on a half-wavelength antenna to create a standing wave with a peak at the middle of the antenna and a node at each end, just as when a string stretched between two points is plucked at the center. In the U.S. bed frames and box springs are made of metal, and the length of a bed is exactly half the wavelength of FM and TV transmissions that have been broadcasting since the late 1940s.
(thx, anna)
Update: So, you know when you run across something about some current scientific theory or hypothesis on a blog or in a magazine or newspaper or even in a scientific journal, there’s a fair chance that whatever the article says is misleading, misstated, or even incorrect. That’s just how it is and if you didn’t know, now you do. Take this stuff with a grain of salt. It’s why I use phrases like “suspected cause” instead of something like “box springs and FM radio proven to cause cancer”.
I don’t post things like this because I think they’re right, I post them because I think they are interesting. The geometry of TV signals and box springs causing cancer on the left sides of people’s bodies in Western countries…that’s a clever bit of hypothesizing, right or wrong.
In this case, an organization I know nothing about (Vetenskap och Folkbildning from Sweden) says that Olle Johansson, one of the researchers who came up with the box spring hypothesis, is a quack. In fact, he was “Misleader of the year” in 2004. What does this mean in terms of his work on box springs and cancer? I have no idea. All I know is that on one side you’ve got Olle Johansson, Scientific American, and the peer-reviewed journal (Pathophysiology) in which Johansson’s hypothesis was published. And on the other side, there’s Vetenskap och Folkbildning, a number of commenters on the SciAm post, and a bunch of people in my inbox. Who’s right? Who knows. It’s a fine opportunity to remain skeptical. (thx, tom)
DNA and quantum entanglement
Does quantum entanglement hold DNA together? Some physicists say it’s possible.
Rieper and co ask what happens to these oscillations, or phonons as physicists call them, when the base pairs are stacked in a double helix.
Phonons are quantum objects, meaning they can exist in a superposition of states and become entangled, just like other quantum objects.
To start with, Rieper and co imagine the helix without any effect from outside heat. “Clearly the chain of coupled harmonic oscillators is entangled at zero temperature,” they say. They then go on to show that the entanglement can also exist at room temperature.
That’s possible because phonons have a wavelength which is similar in size to a DNA helix and this allows standing waves to form, a phenomenon known as phonon trapping. When this happens, the phonons cannot easily escape. A similar kind of phonon trapping is known to cause problems in silicon structures of the same size.
Ancient Roman shipwreck aids in neutrino search
Lead ingots carried by a Roman ship sunk in 50 BC will be used to study the decay of neutrinos. Neutrino experiments are very delicate and need to be shielded from radioactive contamination, including possible contamination from the shielding itself.
This vast stretch of time means that the tiny amount of the radioactive isotope lead-210 originally present in the ingots, just as it exists in any normal lead object, has by now almost completely disappeared.
(via history blog)
Making a tiny star on Earth?
Not content with movie stars, California wants its own actual stellar object. The LIFE project at the NIF (National Ignition Facility) at the Lawrence Livermore National Laboratory aims to create a tiny star with intense laser power. How intense? The facility increases the power of the laser beam a quadrillion times before it reaches its target:
The National Ignition Facility, located at Lawrence Livermore National Laboratory, is the world’s largest laser system… 192 huge laser beams in a massive building, all focused down at the last moment at a 2 millimeter ball containing frozen hydrogen gas. The goal is to achieve fusion… getting more energy out than was used to create it. It’s never been done before under controlled conditions, just in nuclear weapons and in stars. We expect to do it within the next 2-3 years. The purpose is threefold: to create an almost limitless supply of safe, carbon-free, proliferation-free electricity; examine new regimes of astrophysics as well as basic science; and study the inner-workings of the U.S. stockpile of nuclear weapons to ensure they remain safe, secure and reliable without the need for underground testing.
Wow. The fusion will produce high-energy neutrons, which will bombard a material capable of converting their energy into heat, which in turn will make steam and eventually electricity. But it gets even better:
In addition, the LIFE engine design can be “charged” with fission fuel. The resulting fission reactions will produce additional energy that can be harvested for electricity production. Moreover, by using depleted uranium or spent nuclear fuel from existing nuclear power plants in the blanket, a LIFE engine will be capable of burning the by-products of the current nuclear fuel cycle. Because the fusion neutrons are produced independently of the fission process, the fission fuel could be used without reprocessing. In this way, LIFE may be able to consume nuclear waste as fuel, mitigate against further nuclear proliferation, and provide long-term sustainability of carbon-free energy. A LIFE engine, via pure fusion or through the combination of fusion and fission, will generate the steady heat required to drive turbines for generating from 1,000 to 2,500 MW of safe, environmentally attractive electric power 24 hours a day for decades.
Also, free unicorns for everyone!
Can the human eye see individual pixels on iPhone 4?
Phil Plait of Bad Astronomy takes on Steve Jobs’ claim that iPhone 4’s pixels are too small for the human eye to see individually. I have confidence in Plait’s conclusions:
I know a thing or two about resolution as well, having spent a few years calibrating a camera on board Hubble.
He may as well have pulled Marshall McLuhan out from behind a movie poster.
The magic levitating top
When this magnetic top is set spinning over another magnet, it levitates. No superconduction necessary.
(via @ebertchicago)
How to build a time machine
According to Stephen Hawking, there are three good ways to do it.
If we want to travel into the future, we just need to go fast. Really fast. And I think the only way we’re ever likely to do that is by going into space. The fastest manned vehicle in history was Apollo 10. It reached 25,000mph. But to travel in time we’ll have to go more than 2,000 times faster. And to do that we’d need a much bigger ship, a truly enormous machine. The ship would have to be big enough to carry a huge amount of fuel, enough to accelerate it to nearly the speed of light. Getting to just beneath the cosmic speed limit would require six whole years at full power.
Negative Twenty Questions
Physicist John Wheeler devised a variant of the Twenty Questions game called Negative Twenty Questions in which, unbeknownst to the guesser, everyone privately picks their own object, resulting in a game where both the guesser and the object choosers are required to narrow their choice in object with each round.
When returning Joe (let’s call him) asks the standard bigger-than-a-breadbox question, if the first person says no, then the other players, who may have selected objects that are bigger, now have to look around the room for something that fits the definition. And if “Is it Hollow?” is Joe’s next question, then any of the players who chose new and unfortunately solid objects now have to search around for a new appropriate object. As Murch says, “a complex vortex of decision making is set up, a logical but unpredictable chain of ifs and thens.” Yet somehow this steady improvisation finally leads — though not always, there’s the tension — to a final answer everyone can agree with, despite the odds.
Wheeler thought the game resembled how quantum mechanics worked.
Would a lava lamp work on Jupiter?
In order to see if a lava lamp would still function on Jupiter, Neil Fraser built a large centrifuge to try it out. This is the best homemade centrifuge video you’ll see today:
He used the accelerometer on an Android phone to measure the G force.
The centrifuge is a genuinely terrifying device. The lights dim when it is switched on. A strong wind is produced as the centrifuge induces a cyclone in the room. The smell of boiling insulation emanates from the overloaded 25 amp cables. If not perfectly adjusted and lubricated, it will shred the teeth off solid brass gears in under a second. Runs were conducted from the relative safety of the next room while peeking through a crack in the door.
Beams crossed at LHC
CERN finally spun up the Large Hadron Collider and smashed some protons together.
“If you want to discover new particles, you have to produce them; and these new particles are massive. To produce them, you need higher energies. For the first time [on Tuesday], we will be producing particles that have energy 3.5 times higher than the maximum energy achieved so far. […] At the end of the 7 TeV (3.5 TeV per beam) experimental period, the LHC will be shut down for maintenance for up to a year. When it re-opens, it will attempt to create 14 TeV events.
A universe of information
Perhaps the framework of the Universe is information and that forces like gravity are emergent phenomena.
Verlinde suggested that gravity is merely a manifestation of entropy in the Universe. His idea is based on the second law of thermodynamics, that entropy always increases over time. It suggests that differences in entropy between parts of the Universe generates a force that redistributes matter in a way that maximises entropy. This is the force we call gravity.
I’m a sucker for would-be GUTs; this one seems especially interesting to consider.
Quantum mechanics just got REAL
The opening paragraph of the article says it all:
A team of scientists has succeeded in putting an object large enough to be visible to the naked eye into a mixed quantum state of moving and not moving.
Wait, what? Like, WHAT? Ok, let’s start over:
Andrew Cleland at the University of California, Santa Barbara, and his team cooled a tiny metal paddle until it reached its quantum mechanical ‘ground state’ — the lowest-energy state permitted by quantum mechanics. They then used the weird rules of quantum mechanics to simultaneously set the paddle moving while leaving it standing still.
The fuck? In my day, we were taught, with the help of non-graphing calculators and paper notebooks, that quantum mechanics was a lot of wand-wavey nonsense about wave/particle duality that you never had to worry about because it belonged to some magical tiny land that no one visits with their actual eyes. This…this is straight-up magic. [Cue Final Countdown]
The physics of free throw shooting
Attention @THE_REAL_SHAQ: it’s all about parabolas and backspin.
Free-throw success is also improved by adding a little backspin, which pushes the ball downward if it hits the back of the rim. The North Carolina State engineers calculated the ideal rate of free-throw backspin at three cycles per second. That is, a shot that takes one second to reach the basket will make three full revolutions counterclockwise as seen from the stands on the player’s right side.
(via mr)
4 trillion degrees Celsius
Using the Relativistic Heavy Ion Collider at the Brookhaven National Laboratory on Long Island, particle physicists have succeeded in creating quark-gluon plasma, the temperature of which is 4 trillion degrees Celsius (about 250,000 times hotter than the center of the Sun). The plasma is believed to be the state the universe was in a microsecond after its creation.
The departure from normal physics manifested itself in the apparent ability of the briefly freed quarks to tell right from left. That breaks one of the fundamental laws of nature, known as parity, which requires that the laws of physics remain unchanged if we view nature in a mirror.
This happened in bubbles smaller than the nucleus of an atom, which lasted only a billionth of a billionth of a billionth of a second. But in these bubbles were “hints of profound physics,” in the words of Steven Vigdor, associate director for nuclear and particle physics at Brookhaven. Very similar symmetry-breaking bubbles, at an earlier period in the universe, are believed to have been responsible for breaking the balance between matter and its opposite antimatter and leaving the universe with a preponderance of matter.
Black hole simulation
Were you to be close to a black hole, this program shows you what you might observe.
The optical appearance of the stellar sky for an observer in the vicinity of a black hole is dominated by bending of light, frequency shift, and magnification caused by gravitational lensing and aberration. Due to the finite apperture of an observer’s eye or a telescope, Fraunhofer diffraction has to be taken into account. Using todays high performance graphics hardware, we have developed a Qt application which enables the user to interactively explore the stellar sky in the vicinity of a Schwarzschild black hole. For that, we determine what an observer, who can either move quasistatically around the black hole or follow a timelike radial geodesic, would actually see.
For Linux and Windows only, although there are sample videos for non-downloaders or those on other machines.
Nature’s quantum computers
One of the big bummers about quantum computing is the cold temperatures required (hundreds of degrees below zero). However, a number of researchers believe that certain algae and bacteria perform quantum calculations at room temperature.
The evidence comes from a study of how energy travels across the light-harvesting molecules involved in photosynthesis. The work has culminated this week in the extraordinary announcement that these molecules in a marine alga may exploit quantum processes at room temperature to transfer energy without loss. Physicists had previously ruled out quantum processes, arguing that they could not persist for long enough at such temperatures to achieve anything useful.
(via mr)
Einstein’s 1905 chronology
In 1905, Einstein came up with the concept of special relativity, published his paper on the photoelectric effect, finished his doctoral dissertation, devised the E=mc^2 concept, published a paper on Brownian motion, was approved for his doctorate, and turned 26.
So……what have you guys been up to?
Life is but a holographic projection
An experiment to detect gravitational waves may indicate that our universe is a holographic projection.
If this doesn’t blow your socks off, then Hogan, who has just been appointed director of Fermilab’s Center for Particle Astrophysics, has an even bigger shock in store: “If the GEO600 result is what I suspect it is, then we are all living in a giant cosmic hologram.” […] Our everyday experience might itself be a holographic projection of physical processes that take place on a distant, 2D surface.
My socks have been blown so far off they are in a parallel universe. We might be living in the shadow of Flatland. Read the whole thing…it’s noodle-bending throughout. Reminds me of the discovery of cosmic background radiation. (via aegirthor)
Richard Feynman Explains Magnets, Sort of
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.
This is why science is so maddening for some and so great for others.
The gravity of the solar system
Today on xkcd, an illustration showing the gravity wells of our solar system’s planets and some of their moons.
Two of Mars’ tiny moons barely have any gravity at all:
You could escape Deimos with a bike and a ramp. A thrown baseball could escape Phobos.
That’s great, but you forgot Pluto!
The physics of space battles
The logistics of fighting wars in space is a little different than the movies have lead us to believe.
For the same reason that we have Space Shuttle launch delays, we’ll be able to tell exactly what trajectories our enemies could take between planets: the launch window. At any given point in time, there are only so many routes from here to Mars that will leave our imperialist forces enough fuel and energy to put down the colonists’ revolt.
What will the LHC find?
With regard to the Large Hadron Collider, the Higgs boson gets all the press but other potential discoveries could be more exciting and easier to detect.
However, if the theorists are right, before it ever finds the Higgs, the LHC will see the first outline of something far bigger: the grand, overarching theory known as supersymmetry. SUSY, as it is endearingly called, is a daring theory that doubles the number of particles needed to explain the world. And it could be just what particle physicists need to set them on the path to fresh enlightenment.
If you haven’t been keeping up with particle physics for the past few years (as I haven’t), this will bring you up to speed a bit.
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