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How Apple Boot Camp Works


Hard Drive Partitions



Boot Camp software relies on controlling how a Mac boots. To understand how Boot Camp takes control, let’s first look at the Mac boot process. Specifically, we need to look at how a Mac reads and uses its hard drive, which stores the operating systems and all your data.

The hard drive is divided into one or more partitions. A partition is a range of physical addresses on the hard drive. In other words, the partition tells the computer where to read and write bits of data inside the hard drive. Information about the partitions on a hard drive is stored in a partition table.

When you boot your Mac, part of the boot process includes accessing the first few bytes of data of the hard drive. Those first bytes point to the partition table. From there, the partition table indicates which partition has the operating system and other data needed to finish booting the Mac.

Normally, when your Mac is fresh out of the box, it recognizes all the available storage space on your hard drive as one single partition. This is sufficient for most users, and it makes it easy to track your total available hard drive space.

However, if you want to install different operating systems on the same hard drive, you have to create different partitions for them. You could use any disk utility to create and format new partitions. Boot Camp, though, takes care of this partitioning for you. Boot Camp will resize your existing Mac OS partition and create and format a new partition for Windows. Boot Camp could also help in partitioning a separate hard drive if you had multiple hard drives in your Mac.

When you boot, how does the Mac know which partition to target? The partition table has an indicator of which partition to use when booting. Your Mac will look for its operating system on that partition. If you have both Mac and Windows, though, you need some way to select between those partitions. Boot Camp’s role is to automate that selection so you don’t have to worry about partition tables. Using Boot Camp, you’ll have two options for switching between your Mac and Windows partitions:

  • Use the Boot Camp utility to indicate you want to switch to the other partition, and then reboot.
  • Use the Option key during the white splash screen while booting, and select the partition you want to use.

Now that you know what Boot Camp’s doing, let’s look at how to set it up on your Mac.

Boot Camp Alternatives: Linux Boot Loaders and Virtual Machines

Boot Camp is limited to switching between booting to a Mac OS X or a Windows partition. Linux boot loaders are designed to boot any number of operating systems. You can find instructions on the Web for installing and configuring Linux on your Mac alongside Mac OS X and Windows. If you wanted to run Windows within the Mac OS X, or vice versa, you can install virtualization software like VMware or Parallels. Such software is designed to use part of your computer’s resources to run a virtual machine, which imitates the way the operating system runs on a dedicated physical machine.

How Apple Boot Camp Works



Did you know you can use the iPod as a hard drive? Learn how on The Science Channel’s "It’s All Geek To Me."

Science Channel

Back before 2006 (which is like 100 years ago in the technology industry), there was a clear dividing line between Macintosh computers and PCs. Mac OS couldn’t run on PCs, and Microsoft Windows couldn’t run on Macs. This created a great rift between users of each system. It wasn’t unusual to hear heated arguments between two users about which was the better system. A few brave souls tried to take an all-inclusive approach by trying try to run both using virtualization software, but even that presented limitations. If you wanted to use the full features of both operating systems, you’d have to buy both a Mac and a PC.

But in 2006, that all changed. Because in 2006, Apple began moving away from its PowerPC processors and offered Mac hardware with Intel processors like those used in PCs. This introduced the possibility that Windows and Windows-based applications could run on Mac hardware just as they run on PCs. At the same time, Apple released Mac OS X Tiger (10.4), the first Mac OS to support running on Intel processors [source: Apple, Buchanan].

Boot Camp is software developed by Apple, in cooperation with Microsoft, designed to effectively run Windows on Mac hardware. By using Boot Camp, you don’t have to choose whether to install either Mac OS or Windows. Instead, you can install both, and you can switch between them just by rebooting and selecting the other OS.

This article covers how Boot Camp works and how you can set it up on your Mac. Boot Camp has been available as part of Mac OS X since Leopard (10.5), released in 2007. The latest version of Boot Camp as of this writing, Mac OS X Lion (10.7), supports Windows 7 Home Premium, Professional or Ultimate editions [source: Apple].

Before we dive into Boot Camp, let’s look at how the partitions work on your Mac’s hard drive, and how the Mac knows which partition to use when you boot.

How 3-D Gestures Work


Author's Note



I got the idea for this article after my visit to CES 2012. It seems like there’s a new emerging trend at the show every year. In 2012, that trend was the reinvention of the user interface. It seemed like every company was trying to add in gesture and voice control systems into products. But don’t get too excited — it might take a year or two for those innovations to make their way into common consumer electronics.

Related Articles

  • How Microsoft Kinect Works
  • Top 5 Kinect Hacks
  • How the Wii Works
  • How Playstation Move Works
  • How will humans interface with computers in the future?

More Great Links

  • SoftKinetic
  • GestureTek


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  • Iddan, Gavriel J., et al."3D Imaging System." United States Patent & Trademark Office Patent # 7,224,384. http://patft.uspto.gov/netacgi/nph-Parser?Sect2=PTO1&Sect2=HITOFF&p=1&u=/netahtml/PTO/search-bool.html&r=1&f=G&l=50&d=PALL&RefSrch=yes&Query=PN/7224384
  • Krah, Christoph H. "Three-dimensional Imaging and Display System." United States Patent & Trademark Office Patent Application # 20110298798. http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=/netahtml/PTO/srchnum.html&r=1&f=G&l=50&s1=20110298798
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  • Ringbeck, Thorsten. "A 3D Time of Flight Camera for Object Detection." PMDTechnologies GmbH. July 12, 2007. (Feb. 10, 2012) http://www.ifm.com/obj/O1D_Paper-PMD.pdf
  • Silver, William, et al. "Method and Apparatus for Human Interface to a Machine Vision System." United States Patent & Trademark Office Patent # 7,957,554. http://patft.uspto.gov/netacgi/nph-Parser?Sect2=PTO1&Sect2=HITOFF&p=1&u=/netahtml/PTO/search-bool.html&r=1&f=G&l=50&d=PALL&RefSrch=yes&Query=PN/7957554
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How 3-D Gestures Work


Beyond the Lens



The Kinect is probably the most recognizable 3-D gesture system on the consumer market right now, but many more products will be joining it soon.

Kiyoshi Ota/Getty Images

Is 3-D gesture control the interface of the future? That will depend upon the ingenuity of the engineers, the efficiency of the various systems and the behavior of users. Designing a workable user interface is no small task — there are hundreds of failed products that at one time or another were going to revolutionize the way we interact with machines. For 3-D gesture systems to avoid the same fate, they’ll have to be useful and reliable. That doesn’t just depend on technology but user psychology.

If a particular gesture doesn’t make sense to a user, he or she may not be willing to use the system as a whole. You probably wouldn’t want to have to perform the "Hokey Pokey" just to change the channel — but if you do, it’s OK, we don’t judge you. Creating a good system means not only perfecting the technology but also predicting how people will want to use it. That’s not always easy.

There are a few 3-D gesture systems on the market already. Microsoft’s Kinect is probably the system most familiar to the average consumer. It lets you control your Xbox 360 with gestures and voice commands. In 2012, Microsoft announced plans to incorporate Kinect-like functionality into Windows 8 machines. And the hacking community has really embraced the Kinect, manipulating it for projects ranging from 3-D scanning technology to robotics.

At CES 2012, several companies showcased devices that included 3-D gesture recognition. One company, SoftKinetic, demonstrated a time-of-flight system that remained accurate even when objects were just a few inches away from the camera. A time-of-flight system measures distances based on how fast light reflects off an object, based on the speed of light. If companies want to include gesture recognition functions in a computer or tablet, they’ll need to rely on systems that can handle gestures made close to the lens.

In the future, we may see tablets with a form of this gesture- recognition software. Imagine propping a tablet up on your desk and placing your hands in front of it. The tablet’s camera and sensors detect the location of your hands and map out a virtual keyboard. Then you can just type away on your desktop as if you have an actual keyboard under your fingertips, and the system tracks every finger movement.

The real test for 3-D gesture systems comes with 3-D displays. Adding depth to our displays gives us the opportunity to explore new ways to manipulate data. For example, imagine a 3-D display showing data arranged in the form of stacked boxes extending in three dimensions. With a 3-D gesture display, you could select a specific box even if it weren’t at the top of a stack just by reaching toward the camera. These gesture and display systems could create a virtual world that is as immersive as it is flexible.

Will these systems take the place of the tried-and-true interfaces we’ve grown used to? If they do, it’ll probably take a few years. But with the right engineering and research, they could help change the stereotypical image of the stationary computer nerd into an active data wizard.

How 3-D Gestures Work


A Little Light Gesturing



What travels at 299,792,458 meters per second in a vacuum? No, it’s not a dust bunny. It’s light. It might seem like trivia to you, but the speed of light comes in handy when you’re building a 3-D gesture system, particularly if it’s a time-of-flight arrangement.

This type of 3-D gesture system pairs a depth sensor and a projector with the camera. The projector emits light in pulses — typically it’s infrared light, which is outside the spectrum of visible light for humans. The sensor detects the infrared light reflected off everything in front of the projector. A timer measures how long it takes for the light to leave the projector, reflect off objects and return to the sensor. As objects move, the amount of time it takes the light to travel will vary and the computer interprets the data as movements and commands.

Imagine you’re playing a tennis video game using a 3-D gesture system. You stand at the ready, waiting to receive a serve from your highly seeded computer opponent. The 3-D gesture system takes note of where you are in relation to your surroundings — the infrared light hits you and reflects back to the sensor, giving the computer all the data it needs to know your position.

Your opponent serves the ball and you spring into motion, swinging your arm forward to intercept the ball. During this time, the projector continues to fire out pulses of infrared light millions of times per second. As your hand moves away from and then toward the camera, the amount of time it takes for the infrared light to reach the sensor changes. These changes are interpreted by the computer’s software as movement and further interpreted as video game commands. Your video game representation returns the serve, wins a point and the virtual crowd goes wild.

Another way to map out a three-dimensional body is to use a method called structured light. With this approach, a projector emits light — again outside the spectrum of visible light — in a grid pattern. As the grid encounters physical objects, it distorts. A sensor detects this distortion and sends the data to a computer, which measures the distortion. As you move about, your movements will cause the grid to distort in different ways. These differences create the data that the computer needs to interpret your movements as commands.

A 3-D gestures system doesn’t have to rely on a single technological approach. Some systems could use a combination of multiple technologies in order to figure out where you are and what you’re doing.

Getting a Handle on Gestures

Some gesture systems use one or more controllers instead of cameras to detect motion. The Nintendo Wii remote and Sony Move controller are examples. These devices contain additional sensors that detect orientation and acceleration.

What Is String Theory?


String theory is an attempt to unite the two pillars of 20th century physics — quantum mechanics and Albert Einstein's theory of relativity — with an overarching framework that can explain all of physical reality. It tries to do so by positing that particles are actually one-dimensional, string-like entities whose vibrations determine the particles' properties, such as their mass and charge.

This counterintuitive idea was first developed in the 1960s and '70s, when strings were used to model data coming out of subatomic colliders in Europe, according to a website about string theory created by the University of Oxford and the British Royal Society. Strings provided an elegant mathematical way of describing the strong force, one of the four fundamental forces in the universe, which holds together atomic nuclei. [8 Ways You Can See Einstein's Theory of Relativity in Real Life]

The topic remained marginal for many years, until the "string theory revolution" in 1984, when theoreticians Michael Green and John Schwarz produced equations that showed how strings avoided certain inconsistencies plaguing models that described particles as point-like objects, according to the University of Cambridge.

But this first flowering left researchers with five different theories explaining how one-dimensional strings oscillated in a 10-dimensional reality. A second revolution came about in 1995, when physicists showed that these differing ideas were all related and could be combined with another theory called supergravity, which worked in 11 dimensions. That approach generated the current incarnation of string theory.

String theory is one of the proposed methods for producing a theory of everything, a model that describes all known particles and forces and that would supersede the Standard Model of physics, which can explain everything except gravity. Many scientists believe in string theory because of its mathematical beauty. The equations of string theory are described as elegant, and its descriptions of the physical world are considered extremely satisfying.

The theory explains gravity via a particular vibrating string whose properties correspond to that of the hypothetical graviton, a quantum mechanical particle that would carry the gravitational force. That the theory bizarrely requires 11 dimensions to work — rather than the three of space and one of time we normally experience — has not dissuaded physicists who advocate it. They've simply described how the extra dimensions are all curled up in an extremely tiny space, on the order of 10^-33 centimeters, which is small enough that we can't normally detect them, according to NASA.

Researchers have used string theory to try to answer fundamental questions about the universe, such as what goes on inside a black hole, or to simulate cosmic processes like the Big Bang. Some scientists have even attempted to use string theory to get a handle on dark energy, the mysterious force accelerating the expansion of space and time.

But string theory has lately come under greater scrutiny. Most of its predictions are untestable with current technology, and many researchers have wondered if they're going down a never-ending rabbit hole. In 2011, physicists gathered at the American Museum of Natural History for the 11th annual Isaac Asimov Memorial Debate, to discuss whether it made sense to turn to string theory as a viable description of reality.

"Are you chasing a ghost, or is the collection of you just too stupid to figure this out?" teased Neil deGrasse Tyson, director of the museum's Hayden Planetarium, who pointed out that progress on string theory had been patchy in the previous years.

The most recent challenges to string theory have come from the framework itself, which predicts the existence of a potentially huge number of unique universes, as many as 10^500 (that's the number 1 followed by 500 zeroes). This multiverse landscape seemed to provide enough possibilities that, should researchers explore them, they would come across one that corresponded to our own version of reality. But in 2018, an influential paper suggested that not a single one of these myriad hypothetical universes looked like our cosmos; specifically, each lacked a description of dark energy as we currently understand it.

"String theorists propose a seemingly endless amount of mathematical constructions that have no known relationship to observation," Sabine Hossenfelder, a physicist at the Frankfurt Institute for Advanced Studies in Germany who has been critical of string theory, previously told Live Science.

Other researchers maintain that string theory will one day turn up results. Writing in the Physics Today magazine, physicist Gordon Kane of the University of Michigan suggested that with upgrades currently being conducted, the Large Hadron Collider could yield evidence of string theory in the near future. But the theory's ultimate fate is, as yet, unknown.

Additional resources:

  • Watch: Theoretical physicist Michio Kaku explains string theory.
  • 5 Reasons We May Live in a Multiverse
  • Learn more about string theory from the Institute of Physics.

The Questionable Science Behind the New Jack the Ripper Claim


Did the analysis of a silk shawl just provide a major clue in one of London's coldest cases, the identity of Jack the Ripper?

No. It doesn't. Not at all. That's according to two experts, a geneticist and a Ripperologist (a Jack the Ripper historian), who spoke with Live Science about the new study.

In fact, this study has so many holes in it — including the provenance of the shawl, contamination of genetic material on the shawl, and the methods used to analyze this genetic material — that it's a wonder it was published at all, said Turi King, a reader in genetics and archaeology at the University of Leicester, who was not involved in the study. [10 Biggest Historical Mysteries That Will Probably Never Be Solved]

Jack the Ripper is notorious for killing and mutilating five women in London in just three months during 1888. According to the new study, a silk shawl was found by the body of Catherine Eddowes, a victim killed by Jack the Ripper during the early morning hours of Sept. 30, 1888.

Acting Sgt. Amos Simpson reportedly took this 8-foot-long (2.4 meters) shawl from the crime scene; the shawl was reportedly passed down through his family for generations until it was sold in 2007 to amateur sleuth Russell Edwards, who made it available to scientists for study.

Soon after, descendants of Eddowes and one of the top suspects, Aaron Kosminski, who at the time was a 23-year-old Polish barber, were located by study lead researcher Jari Louhelainen, a senior lecturer of molecular biology at Liverpool John Moores University in the United Kingdom. Then, with study co-researcher David Miller, a reproduction and sperm expert at the University of Leeds in the United Kingdom, Louhelainen looked at mitochondrial DNA (genetic material passed down by mothers) on the shawl.

The researchers found the genetic material on the shawl matched the descendants of Eddowes and Kosminski. The analysis also revealed, the researchers claim, that the killer was a man with brown hair and brown eyes, which matches an eyewitness account from that time.

"Although these characteristics are surely not unique, they fully support our hypothesis," the researchers wrote in the study, published online March 12 in the Journal of Forensic Sciences. It's unknown how common brown eyes and hair were in 1888, but today in England blue eyes are more common, the researchers noted.

These results were initially made public five years ago in Edwards' book "Naming Jack the Ripper" (Lyons Press, 2014), but this is the first published study on the analysis.

First and foremost, it's doubtful that the shawl belonged to Eddowes, Jack the Ripper's fourth victim.

London has two police forces. Most of the Jack the Ripper murders happened under the jurisdiction of the Metropolitan Police Service, a force that operates out of Scotland Yard. But Eddowes was killed in an area overseen by the City of London Police.

Acting Sgt. Simpson worked for Scotland Yard, so it's unclear why he would have been working on Eddowes' case, given that it was a City of London Police case, said Paul Begg, a U.K.-based author who has written six historical books about Jack the Ripper, and was not involved with the new study. What's more, Simpson's patrolling area wasn't anywhere near the spot where Eddowes was murdered, so it's strange he would have gone out of his way to travel to the scene of the crime and take the shawl, Begg said. [Crime Scene Photos: These Items Came from UK's Most Infamous Cases]

On top of that, "there's no evidence that a shawl was connected with Catherine Eddowes' murder anyway," Begg told Live Science. "Effectively, the provenance of the shawl is extremely bad."

He added that this particular eyewitness account of Jack the Ripper is dubious. Three men who had just left a social club saw a woman talking to a man in the same location where Eddowes was found dead shortly thereafter. But it's unknown if this man and women were in fact Jack the Ripper and Eddowes. Moreover, only one of those men got a good look at the mystery man, Begg said.

The researchers of the study did not respond to a request for comment.

The genetic analysis of the shawl is also unconvincing, said King, who is known for her work sequencing the whole genome of King Richard III.

The shawl has been handled by countless people over the years, meaning that their DNA got on the shawl, contaminating it, King said.

It's her understanding that the descendants of Eddowes and Kosminski, who took part in the new study, were in the presence of the shawl. "So, all you need to do is breathe anywhere near the shawl and they could end up putting their DNA on it," King said.

In the study itself, the researchers are vague on how they did the analysis. It's key that scientists describe their methods clearly, as it allows other scientists to assess them and even try to reproduce the results, King said. Furthermore, it's strange that the researchers say they looked at a maternal descendant of Kosminski, given that men can't pass on mitochondrial DNA. In fact, the researchers didn't say how the descendants were related to Eddowes and Kosminski (even though the descendant of Eddowes was named by The Independent in 2014), nor did they publish these people's full mitochondrial DNA sequences, citing privacy reasons.

That's problematic, King said. The researchers claimed to have the entire mitochondrial DNA genome, but they only looked at a couple of mitochondrial DNA segments. And they did it at such low resolution, the results could be similar in large swaths of people.

"At that low resolution, it could be that thousands and thousands and thousands of people share the mitochondrial DNA types that they're finding," King said. "The fact that there's a match with a relative, who may or may not have breathed on the shawl in the first place … statistically, that's not very strong evidence."

As for privacy reasons, the researchers weren't sensitive to the fact that by naming Kosminski, they were associating his living relatives with a notorious murderer, King said. In King's study of Richard III, she used genetic material from two of his living female-line relatives, both of whom gave their informed consent that their mitochondrial DNA be made public. King wonders if the researchers explained the science and asked for the informed consent at all. Plus, given that these particular mitochondrial DNA analysis was so vague, it wouldn't have identified the descendants anyway, King said.

With all of these caveats, does the new paper offer any clues on the Jack the Ripper case?

"No, sadly not," King said. "For all we know, Kosminski was Jack the Ripper, but this paper unfortunately does not tell us that."

  • Photos: In Search of the Grave of King Richard III
  • The 25 Most Mysterious Archaeological Finds on Earth
  • 19 of the World's Oldest Photos Reveal a Rare Side of History

Originally published on Live Science.

Giant, Weird-Looking Fish With ‘Startled’ Eyes Washes Up on Aussie Beach


When a group of Aussies spotted the behemoth on the beach, they initially thought it was a rugged piece of driftwood. Upon closer inspection, however, they realized it was the body of an enormous, bony fish.

That's how they came face to face with the mighty ocean sunfish, known to scientists as the Mola mola. These fish can grow up to 11 feet (3.3 meters) long and weigh up to 2.5 tons (2.2 metric tons), according to National Geographic.

Linette Grzelak, whose partner, Steven Jones, sent her a photo of the dead fish, related that he "said it was extremely heavy and the skin felt hard and leathery like a rhinoceros." [In Photos: The World's Largest Bony Fish]

Jones is a supervisor of a cockle-fishing crew, which drives that stretch of beach for work. "I'm always getting sent photos of what they find, but it's mostly sharks and seals," Grzelak told Live Science. "Saturday night [March 16], I got sent the sunfish and thought it was fake. I had no idea what it was."

Ocean sunfish are among the largest known bony fish in the world.
Credit: Linette Grzelak

These fish are rarely seen in that neck of the woods, in South Australia at the mouth of the Murray River, which is the longest river in Australia. But M. mola fish have a wide range; they're known to live all over the world, mostly in temperate and tropical waters.

Despite their size, ocean sunfish do not prey on humans. Instead, they feast on small and soft animals, like jellyfish and zooplankton, according to a 2010 study in the journal Reviews in Fish Biology and Fisheries. However, Jones said he "has heard stories over the years about sunfish sinking yachts in races and the damage they do to boats," Grzelak noted.

In addition to their impressive dimensions, ocean sunfish are recognizable for their wide eyes, which make them look like they're constantly startled, and their tall fins are often mistaken for those of sharks when they breach the water's surface, according to Two Oceans Aquarium in Cape Town, South Africa. In addition, they lack a true tail, researchers reported in 2008 in the journal PLOS One.

Though enormous, these fish pose no danger to humans. Rather, they eat jellyfish and zooplankton.
Credit: Linette Grzelak

After the cockle-fishing crew found the sunfish, they took photos that were later posted to iNaturalist, a crowdsourcing site that scientists use to identify species. The consensus was that the fish was an ocean sunfish.

However, the fish is now lost to the sea. The crew didn't have time to save the deceased animal's body, because they were working. Moreover, that stretch of beach is accessible only by boat, is a low-traffic site that is mainly visited only by fisheries and doesn't have cellphone reception. So, the team couldn't call anyone to collect the fish before it was washed back to sea by the tide, Grzelak said.

Given that there weren't any visible signs of damage on the fish, "there is the assumption that it died of either natural causes, eating too much plastic or parasites," according to scientists who consulted with the team about the fish, Grzelak said.

Another species of sunfish made the news a few weeks ago, too; a hoodwinker sunfish (Mola tecta), a species discovered by scientists in 2017, washed ashore near Santa Barbara, California, thousands of miles from its known home in the Southern Hemisphere.

  • Photos: The Freakiest-Looking Fish
  • Moonfish: The First Warm-Blooded Fish (Photos)
  • In Photos: 'Faceless' Fish Rediscovered After More Than a Century

Originally published on Live Science.

Physicists Think They’ve Figured Out the Most Extreme Chemical Factories in the Universe


Our world is full of chemicals that shouldn't exist.

Lighter elements, like carbon and oxygen and helium, exist because of intense fusion energies crushing protons together inside stars. But elements from cobalt to nickel to copper, up through iodine and xenon, and including uranium and plutonium, are just too heavy to be produced by stellar fusion. Even the core of the biggest, brightest sun isn't hot and pressurized enough to make anything heavier than iron.

And yet, those chemicals are abundant in the universe. Something is making them. [Elementary, My Dear: 8 Elements You Never Heard Of]

The classic story was that supernovae — the explosions that tear some stars apart at the end of their lives — are the culprit. Those explosions should briefly reach energies intense enough to create the heavier elements. The dominant theory for how this happens is turbulence. As the supernova tosses material into the universe, the theory goes, ripples of turbulence pass through its winds, briefly compressing outflung stellar material with enough force to slam even fusion-resistant iron atoms into other atoms and form heavier elements.

But a new fluid dynamics model suggests that this is all wrong.

"In order to initiate this process we need to have some sort of excess of energy," said study lead author Snezhana Abarzhi, a materials scientist at the University of Western Australia in Perth. "People have believed for many years that this sort of excess might be created by violent, fast processes, which might essentially be turbulent processes," she told Live Science.

But Abarzhi and her co-authors developed a model of the fluids in a supernova that suggest something else — something smaller — might be going on. They presented their findings earlier this month in Boston, at the American Physical Society March meeting, and also published their findings Nov. 26, 2018 in the journal Proceedings of the National Academy of Sciences.

In a supernova, stellar material blasts away from the star’s core at high speed. But all that material is flowing outward at about the same speed. So relative to one another, the molecules in this stream of stellar material aren't moving all that fast. While there may be the occasional ripple or eddy, there's not enough turbulence to create molecules past iron on the periodic table.

Instead, Abarzhi and her team found that fusion likely takes place in isolated hotspots within the supernova.

When a star explodes, she explained, the explosion isn't perfectly symmetrical. The star itself has density irregularities in the moment before an explosion, and the forces blasting it apart are also a bit irregular.

Those irregularities produce ultradense, ultrahot regions within the already-hot fluid of the exploding star. Instead of violent ripples shaking the whole mass, the supernova’s pressures and energies get especially concentrated in small parts of the exploding mass. These regions become brief chemical factories more powerful than anything that exists in a typical star.

And that, Abarzhi and her team suggest, is where all the heavy elements in the universe come from.

The big caveat here is that this is a single result and a single paper. To get there, the researchers relied on pen-and-paper work, as well as computer models, Abarzhi said. To confirm or refute these results, astronomers will have to match them against the actual chemical signatures of supernovae in the universe — gas clouds and other remainders of a stellar explosion.

But it seems like scientists are a bit closer to understanding how much of the material all around us, including inside our own bodies, gets made.

  • Gallery: Our Amazing Sun
  • Fiery Folklore: 5 Dazzling Sun Myths
  • The 12 Strangest Objects in the Universe

Originally published on Live Science.

The ‘True’ Neutrino Has Hidden from Physicists for Decades. Could They Find It in Antarctica?


Neutrinos are perhaps the most puzzling of the known particles. They simply flout all the known rules of how particles ought to behave. They scoff at our fancy detectors. Like cosmic cats, they traipse throughout the universe without worry or care, occasionally interacting with the rest of us, but really only when they feel like it, which honestly isn't all that often.

Most frustrating of all, they wear masks and never look the same way twice.

But a new experiment may have taken us just a step closer to ripping off those masks. Revealing the true neutrino identity could help answer long-standing questions, like whether neutrinos are their own antimatter partners, and it could even help unify the forces of nature into one cohesive theory. [The 18 Biggest Unsolved Mysteries in Physics]

Neutrinos are weird. There are three kinds: the electron neutrino, the muon neutrino and the tau neutrino. (There are also the antiparticle versions of those three, but that's not a big part of this story.) They are so named because these three kinds get to party with three different kinds of particles. Electron neutrinos join interactions involving electrons. Muon neutrinos get paired up with muons. No points will be awarded for guessing what the tau neutrino interacts with.

So far, that's not weird at all. Here comes the strange part.

For particles that are not neutrinos — like electrons, muons and tau particles — what you see is what you get. Those particles are all exactly the same except for their masses. If you spot a particle with the mass of an electron, it will behave exactly like an electron should behave, and the same goes for the muon and the tau. What's more, once you spot an electron, it will always be an electron. Nothing more, nothing less. Same for the muon and the tau.

But the same does not go for their cousins, the electron, muon and tau neutrinos.

What we call, say, the "tau neutrino" isn't always the tau neutrino. It can change its identity. It can become, midflight, an electron or muon neutrino.

This weird phenomenon that basically nobody was expecting is called neutrino oscillation. It means, among other things, that you may create an electron neutrino and send it over to your best friend as a present. But by the time they get it, they may be disappointed to find a tau neutrino instead.

For technical reasons, the neutrino oscillation works only if there are three neutrinos with three different masses. But the neutrinos that oscillate are not the electron-, muon- and tau-flavored neutrinos.

Instead, there are three "true" neutrinos, each with different, but unknown masses. A distinct mix of these true, fundamental neutrinos creates each of the neutrino flavors we detect in our laboratories (electron, muon, tau). So, the lab-measured mass is some mixture of those true neutrino masses. Meanwhile, the mass of each true neutrino in the mix governs how often it morphs into each of the different flavors. [Images: Inside the World's Top Physics Labs]

The job for physicists now is to disentangle all the relationships: What are the masses of those true neutrinos, and how do they mix together to make the three flavors?

So, physicists are on a hunt to uncover the masses of the "true" neutrinos by looking at when and how often they switch flavors. Again, the physics jargon is very unhelpful when explaining this, as the names of these three neutrinos are simply m1, m2 and m3.

A variety of painstaking experiments have taught scientists some things about the masses of the true neutrinos, at least indirectly. For example, we know about some of the relationships between the square of the masses. But we don't know exactly how much any of the true neutrinos weigh, and we don't know which ones are heavier.

It could be that m3 is the heaviest, far outweighing m2 and m1. This is called "normal ordering" because it seems pretty normal — and it's the ordering physicists essentially guessed decades ago. But based on our current state of knowledge, it could also be that m2 is the heaviest neutrino, with m1 not far behind and m3 puny in comparison. This scenario is called "inverted ordering," because it means we guessed the wrong order initially.

Of course, there are camps of theorists pining for each of these scenarios to be true. Theories that attempt to unify all (or at least most) of the forces of nature under a single roof typically call for normal neutrino-mass ordering. On the other hand, inverted-mass ordering is necessary for the neutrino to be its own antiparticle twin. And if that was true, it could help explain why there is more matter than antimatter in the universe.

Which is it: normal or inverted? That's one of the biggest questions to spring up from the past couple decades of neutrino research, and it's exactly the kind of question that the massive IceCube Neutrino Observatory was designed to answer. Located at the South Pole, the observatory consists of dozens of strings of detectors sunk into the Antarctic Ice Sheet, with a central "DeepCore" of eight strings of more-efficient detectors capable of seeing lower-energy interactions.

Neutrinos barely talk to normal matter, so they're perfectly capable of jetting straight through the body of Earth itself. And as they do so, they will morph into the various flavors. Every once in a rare while, they will strike a molecule in the Antarctic Ice Sheet near the IceCube detector, triggering a cascading shower of particles that emit a surprisingly blue light called Cherenkov radiation. It's this light that the IceCube strings detect.

An illustration of a neutrino zooming through the clear Antarctic ice. Occasionally, a neutrino may interact with the ice and trigger a cascading shower of particles that leave trails of blue light in the detector.
Credit: Nicolle R. Fuller/NSF/IceCube

In a recent paper published on the pre-print journal arXiv, IceCube scientists used three years of DeepCore data to measure how many of each kind of neutrino passed through Earth. Progress is slow, of course, because neutrinos are so hard to catch. But in this work. the scientists report a slight preference in the data for normal ordering (which would mean we guessed right decades ago). However, they've found nothing too conclusive yet.

Is this all we'll get? Certainly not. IceCube is preparing for a major upgrade soon, and new experiments like the Precision IceCube Next Generation Upgrade (PINGU) and Deep Underground Neutrino Experiment (DUNE) are gearing up to tackle this central question too. Who knew that such a simple question about the ordering of neutrino masses would reveal so much of the way the universe works? It's too bad it's also not an easy question.

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Paul M. Sutter is an astrophysicist at The Ohio State University, host of "Ask a Spaceman" and "Space Radio," and author of "Your Place in the Universe."

Originally published on Live Science.