Explore the history of the frame rate - the engine that gives motion to the motion picture from their earliest versions in silent pictures to the frame rates of broadcast television.
This lesson is proudly sponsored by RØDE Microphones:
The evolution of human culture is often compared to biological evolution, and it’s easy to see why: both involve variation across a population, transmission of units from one generation to the next, and factors that ensure the survival of some variants and the death of others. However, sometimes this comparison fails. Culture, for instance, can be transmitted “horizontally” between members of the same generation, but genes can’t.
“Little is known about whether human demographic history generates patterns in linguistic data that are similar to those found in genetic data,” write the authors of a recent paper in PNAS. Both linguistic and genetic data can be used to draw conclusions about human history, but it's vital to understand how the forces affecting them differ in order to be sure that the conclusions we're drawing are accurate.
By conducting a large-scale analysis on global genetic and linguistic data, the researchers found that languages sometimes behave in ways very unlike genetics. For instance, isolated languages have more, not less, diversity, and languages don't retain the echo of a migration out of Africa—unlike our genomes.
In 2011, researchers announced that they had reprogrammed the genome of the bacteria E. coli, changing it so that one of DNA's methods of encoding information went unused. While a technological tour-de-force, the scientists didn't actually do anything with the newly available bit of genetic code. Now a few years later, two different groups have used it to accomplish the same end: creating genetically modified organisms that may never be able to escape into the wild.
All forms of life we're aware of use what's called a triplet code: it takes three bases in a row in order to encode for one of the amino acids that make up a protein. A series of triplets, stretched out along the DNA, can be read to determine the precise order of amino acids. At the end of the list of amino acid codes, you'll find what's called a stop codon. The three stop codons (TAA, TAG, and TGA in their DNA form) don't code for any amino acids, which the cell interprets as an indication to terminate translation of codes into amino acids.
Since there are three stop codons that mean essentially the same thing, the earlier work involved replacing all instances of one of them (TAG) with a different one (TAA). The editing process preceded in stages but, by the time it was done, all 314 cases where TAG was used as a stop codon had been replaced. This, in effect, freed up TAG to encode something else, such as an artificial amino acid.
Update: SpaceX confirmed that it had received $1 billion in funding from Google and Fidelity Investments. The two companies will together own slightly less than 10 percent of the company. "This funding will be used to support continued innovation in the areas of space transport, reusability, and satellite manufacturing," SpaceX said in a short statement on its website.
Speaking to Ars, a Google spokesperson added, “Space-based applications, like imaging satellites, can help people more easily access important information, so we’re excited to support SpaceX’s growth as it develops new launch technologies.”
Ars has contacted Fidelity for a statement and will update if we receive a response.
It was an interesting week for ideas about the future of the Internet. On Wednesday, satellite industry notable Greg Wyler announced that his company OneWeb, which wants to build a micro-satellite network to bring Internet to all corners of the globe, secured investments from Richard Branson's Virgin Group and Qualcomm. Then in a separate announcement on Friday, Elon Musk said that he would also be devoting his new Seattle office to creating "advanced micro-satellites" to deliver Internet.
OneWeb, formerly WorldVu Satellites Ltd, aims to target rural markets, emerging markets, and in-flight Internet services on airlines, the Wall Street Journal reported. Both Branson and Qualcomm Executive Chairman Paul Jacobs will sit on the company's board, but Wyler did not say how much Virgin and Qualcomm invested in his company.
Wyler said that his company's goal is to create a network of 648 small satellites that would weigh in at around 285 pounds each. The satellites would be put in orbit 750 miles above the Earth and ideally cost about $350,000 each to build using an assembly line approach. Wyler also said that Virgin, which has its own space segment, would be launching the satellites into orbit. “As an airline and mobile operator, Virgin might also be a candidate to resell OneWeb’s service,” the Journal noted. Wyler has said that he projects it to take $1.5 billion to $2 billion to launch the service, and he plans to launch in 2018.
Today, under the heading of "Close, but no cigar," SpaceX released video of its Falcon 9 booster's failed landing following last weekend's successful launch. This was the company's first attempt at retrieving one of its boosters for reuse, and it publicly stated that it wasn't expecting success on the first try. But the video will clearly provide some information on what went wrong with the landing.
It shows the booster drifting above the barge that was its intended landing site; the lighting makes it a bit difficult to tell whether the rocket was oriented vertically at that point. Then, as it was clearly off target and headed past the far end of the barge, the booster tilted heavily in order to re-center itself on the landing site. Unfortunately, it was quite low by that point, and it ended up striking the barge while leaning heavily to one side. That set off the explosion of its remaining fuel, scattering rocket parts out into the ocean.
The majority of stars in our galaxy, and most likely the Universe as a whole, are small, (relatively) dim, low mass bodies. Because they emit much less light, the habitable zone for these stars is close in, where planets would take weeks to complete a full orbit. That's also close enough where the star's gravity can create tidal interactions with the planet's interior, slowing its spin until the planet perpetually shows a single face to the star (much like our Moon does to Earth).
Needless to say, leaving one side of the planet perpetually in the dark could have some rather interesting effects on the environment, including the idea of an "eyeball Earth." That's where the area facing the host star is melted while the rest of the planet remains a frozen wasteland. But now some researchers have suggested eyeball Earths may be a rarity: an atmosphere like Earth's is enough to keep a body from becoming tidally locked.
The tidal forces we recognize most easily are (duh) the tides on Earth, which are pulled around by the Moon's orbit. But tidal forces also operate on a moon or planet's flexible interior, creating a friction that gradually slows the body's rotation. That's why many of the moons in our Solar System are tidally locked, even though there aren't any oceans to be seen. (Although the internal friction may melt enough of the interior to create internal oceans.)
When galaxies collide, they tend to intermingle, ultimately forming a new, merged galaxy. And the supermassive black holes from the original galaxies’ cores should generally end up at the core of the new galaxy, according to current models. Some models predict that the two supermassive black holes could orbit each other, forming a black hole binary system. However, until recently, this has proved difficult to actually observe. Current instruments can’t resolve the difference between two supermassive black holes like these, which could be significantly less than a parsec apart.
But by using alternative methods, recent searches have found some promising candidates that could be supermassive black hole binary systems. In a new study, a team of researchers has reported a strong, clear signal from an extremely bright quasar that appears to be an example of a black hole binary. While this identification is still uncertain, the researchers conclude it’s the most plausible explanation of the behavior of that quasar.
Quasars are simply extremely bright supermassive black holes, with the intense light originating from their jets and accretion disks. The jets, which emerge at each pole, are probably caused by their magnetic fields interacting with their spin and mass. The black hole also often has a disk of material falling in, called an accretion disk, that can produce a lot of light, since the infalling material is hot from friction.
When piecing together the story of human capabilities, one of the most useful sources of evidence available is the presence or absence of an ability in other species. Humans make art; chimpanzees do not. This gives us some clues about the time bracket where we should search for the emergence of symbolic and abstract thinking.
It wasn’t clear whether extinct species of humans like Neanderthals engaged in these behaviors until earlier this year, when a group of researchers announced evidence of Neanderthal etchings in a cave wall from more than 39,000 years ago. Now, a new paper in Nature reports a more startling discovery: etchings on a shell that date back to 500,000 years ago, created by an entirely different species: Homo erectus. The shell was actually found with the first Homo erectus skeleton, Java Man, but has sat in a collection until recently re-analyzed.
The intentional creation of abstract patterns is seen as a major step in cognitive evolution, no matter how simple the patterns. It is “generally interpreted as indicative of modern cognition and behavior,” write the researchers who discovered the shell etchings. If Homo erectus was carving abstract patterns, it means that they were capable of more advanced cognition and motor control than previously thought.
In this surprisingly interesting video from Jerobeam Fenderson we watch (and listen) as he explains how to draw images using the visualizations of sound waves on an old analog Tektronix oscilloscope. To be clear: the images you’re seeing here are not being animated through software, instead Fenderson creates waveforms (sounds) using his computer, and those sound waves LOOK LIKE THIS when fed into an oscilloscope. Suffice to say there’s lots of math involved, and it’s all a little bit over my head, but luckily he answers some questions over on his blog about how it all works. Make sure to watch through to the end.
Yesterday, the European Southern Observatory released the first images taken with the upgraded version of its ALMA telescope. The images capture a disk of material orbiting the young star HL Tauri in exquisite detail, showing gaps in the disk that are likely to be created by the formation of larger, potentially planet-sized bodies.
ALMA stands for the Atacama Large Millimeter/submillimeter Array. As its name implies, it's located in the Atacama Desert, one of the driest regions on the planet. It's also placed at 5,000 meters above sea level; the combination limits the imaging complications posed by Earth's atmosphere. ALMA is an array of multiple individual telescopes, with the final image constructed by mathematically processing the input of each individual telescope.
The final resolution of these images depends on the distance among the telescopes, and ALMA has just received an upgrade that places them up to 15 kilometers apart. This is close to the planned final configuration (which will allow 16km separations) and much larger than previous telescopes that imaged at this wavelength, which were limited to separations of about 2km.
A type of star that I hold dear is the pulsar (a type of neutron star). Not just because the first one discovered was called LGM-1 (Little Green Men), but because they are a rich mixture of quantum physics, electromagnetism, and gravity, all in a single macroscopic object. For a young graduate student, being able to solve a set of equations and describe (at a simple level) the behavior of an entire freaking star is just mind-blowing.
But they are also a huge mystery, having a complex structure and possibly mountains. Another mystery that's not inherent to the objects themselves is that neutron stars of a certain type are conspicuous by their absence in the galactic center. There are many possible reasons for this absence—maybe there aren't any good schools in the neighborhood or it's too far to the local pub—but one of the most exciting possibilities is that the heaviest neutron stars are being hunted down and devoured by dark matter.
Neutron stars are essentially the corpses of stars. After burning through all their fuel and exploding in a last furious burst of energy, the remaining matter collapses in on itself. The temperature and pressure get so high that the electrons and protons fuse to form neutrons. However, their mass isn't sufficient for gravity to force the neutrons together—if it were, a black hole would form.
The pressure that prevents a neutron star from collapsing is called the Fermi pressure. Neutrons are fermions, which means they repel each other. Fermions cannot occupy the same quantum state, so at close range, they stack in energy and space themselves out. This unusual state also generates huge magnetic fields, which accelerates charged particles to enormous energies as the star spins. These particles emit beams of radiation that sweep around like the beam from a light house. When we happen to fall in the path of this beam, we record this as a regular blip of light.
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Geology rewards an active imagination. It gives us a lot of tantalizing clues about very different times and places in Earth’s history, leaving us to try to answer “Man, what would that be like?” One of the things that's tough to imagine involves changing something that most of us never give a second thought—the fact that compasses point north. That’s plainly true today, but it hasn’t always been.
What we call the “north” magnetic pole—the object of your compass’ affection—doesn’t need to be located in the Arctic (it noticeably wanders there, by the way). It feels equally at home in the Antarctic. The geologic record tells us that the north and south magnetic poles frequently trade places. In fact, the signal of this magnetic flip-flopping recorded in the seafloor was the final key to the discovery of plate tectonics, as it let us see how ocean crust forms and moves over time.
That the poles flip is interesting in itself, but “Man, what would that be like?” Does the magnetic pole slowly walk along the curve of the Earth over thousands of years, meaning your compass might have pointed to some part of the equator for long stretches of time? Do the poles weaken to nothing, disappearing for a while before re-emerging in the new configuration? Do they somehow flip in the blink of an eye? Given the number of species that use the Earth’s magnetic field to navigate—especially for seasonal migrations—this is more than an academic curiosity.