[The following is an exact transcript of this podcast.]
The earth’s crust is old. Billions of years old. So old that it’s nearly impossible to imagine. And now scientists have discovered what may be the oldest whole rocks ever known. Geologists at Carnegie Melon University published the results of the research in the September 26th issue of the journal Science. [More]
[The following is an exact transcript of this podcast.]
The earth’s crust is old. Billions of years old. So old that it’s nearly impossible to imagine. And now scientists have discovered what may be the oldest whole rocks ever known. Geologists at Carnegie Melon University published the results of the research in the September 26th issue of the journal Science. [More]
In 1937 the great neuroscientist Sir Charles Scott Sherrington of the University of Oxford laid out what would become a classic description of the brain at work. He imagined points of light signaling the activity of nerve cells and their connections. During deep sleep, he proposed, only a few remote parts of the brain would twinkle, giving the organ the appearance of a starry night sky. But at awakening, “it is as if the Milky Way entered upon some cosmic dance,” Sherrington reflected. “Swiftly the head-mass becomes an enchanted loom where millions of flashing shuttles weave a dissolving pattern, always a meaningful pattern though never an abiding one; a shifting harmony of subpatterns.”
Although Sherrington probably did not realize it at the time, his poetic metaphor contained an important scientific idea: that of the brain revealing its inner workings optically. Understanding how neurons work together to generate thoughts and behavior remains one of the most difficult open problems in all of biology, largely because scientists generally cannot see whole neural circuits in action. The standard approach of probing one or two neurons with electrodes reveals only tiny fragments of a much bigger puzzle, with too many pieces missing to guess the full picture. But if one could watch neurons communicate, one might be able to deduce how brain circuits are laid out and how they function. This alluring notion has inspired neuroscientists to attempt to realize Sherrington’s vision.
[More]In 1937 the great neuroscientist Sir Charles Scott Sherrington of the University of Oxford laid out what would become a classic description of the brain at work. He imagined points of light signaling the activity of nerve cells and their connections. During deep sleep, he proposed, only a few remote parts of the brain would twinkle, giving the organ the appearance of a starry night sky. But at awakening, “it is as if the Milky Way entered upon some cosmic dance,” Sherrington reflected. “Swiftly the head-mass becomes an enchanted loom where millions of flashing shuttles weave a dissolving pattern, always a meaningful pattern though never an abiding one; a shifting harmony of subpatterns.”
Although Sherrington probably did not realize it at the time, his poetic metaphor contained an important scientific idea: that of the brain revealing its inner workings optically. Understanding how neurons work together to generate thoughts and behavior remains one of the most difficult open problems in all of biology, largely because scientists generally cannot see whole neural circuits in action. The standard approach of probing one or two neurons with electrodes reveals only tiny fragments of a much bigger puzzle, with too many pieces missing to guess the full picture. But if one could watch neurons communicate, one might be able to deduce how brain circuits are laid out and how they function. This alluring notion has inspired neuroscientists to attempt to realize Sherrington’s vision.
[More]Editor's Note: This story was originally printed in the February 2004 issue of Scientific American. We are reposting this story because author Adam Riess was selected as a MacArthur Fellow in 2008 by the MacArthur Foundation.
From the time of Isaac Newton to the late 1990s, the defining feature of gravity was its attractive nature. Gravity keeps us grounded. It slows the ascent of baseballs and holds the moon in orbit around the earth. Gravity prevents our solar system from flying apart and binds together enormous clusters of galaxies. Although Einstein’s general theory of relativity allows for gravity to push as well as pull, most physicists regarded this as a purely theoretical possibility, irrelevant to the universe today. Until recently, astronomers fully expected to see gravity slowing down the expansion of the cosmos.
[More]Editor's Note: This story was originally printed in the February 2004 issue of Scientific American. We are reposting this story because author Adam Riess was selected as a MacArthur Fellow in 2008 by the MacArthur Foundation.
From the time of Isaac Newton to the late 1990s, the defining feature of gravity was its attractive nature. Gravity keeps us grounded. It slows the ascent of baseballs and holds the moon in orbit around the earth. Gravity prevents our solar system from flying apart and binds together enormous clusters of galaxies. Although Einstein’s general theory of relativity allows for gravity to push as well as pull, most physicists regarded this as a purely theoretical possibility, irrelevant to the universe today. Until recently, astronomers fully expected to see gravity slowing down the expansion of the cosmos.
[More]
OCTOBER 1958 [More]
OCTOBER 1958 [More]
[The following is an exact transcript of this podcast.]
[More][The following is an exact transcript of this podcast.]
[More]The visual image is inherently ambiguous: an image of a person on the retina would be the same size for a dwarf seen from up close or a giant viewed from a distance. Perception is partly a matter of using certain assumptions about the world to resolve such ambiguities. We can use illusions to uncover what the brain’s hidden rules and assumptions are. In this column, we consider illusions of shading.
In illustration a, the disks are ambiguous; you can see either the top row as convex spheres or “eggs,” lit from the left, and the bottom row as cavities--or vice versa. This observation reveals that the visual centers in the brain have a built-in supposition that a single light source illuminates the entire image, which makes sense given that we evolved on a planet with one sun. By consciously shifting the light source from left to right, you can make the eggs and cavities switch places.
[More]The visual image is inherently ambiguous: an image of a person on the retina would be the same size for a dwarf seen from up close or a giant viewed from a distance. Perception is partly a matter of using certain assumptions about the world to resolve such ambiguities. We can use illusions to uncover what the brain’s hidden rules and assumptions are. In this column, we consider illusions of shading.
In illustration a, the disks are ambiguous; you can see either the top row as convex spheres or “eggs,” lit from the left, and the bottom row as cavities--or vice versa. This observation reveals that the visual centers in the brain have a built-in supposition that a single light source illuminates the entire image, which makes sense given that we evolved on a planet with one sun. By consciously shifting the light source from left to right, you can make the eggs and cavities switch places.
[More]Editor's Note: This story was originally published in the March 2004 issue of Scientific American.
In early November 2000 the Big Island of Hawaii experienced its largest earthquake in more than a decade. Some 2,000 cubic kilometers of the southern slope of Kilauea volcano lurched toward the ocean, releasing the energy of a magnitude 5.7 shock. Part of that motion took place under an area where thousands of people stop every day to catch a glimpse of one of the island’s most spectacular lava flows. Yet when the earthquake struck, no one noticed--not even seismologists. How could such a notable event be overlooked?
[More]Editor's Note: This story was originally published in the March 2004 issue of Scientific American.
In early November 2000 the Big Island of Hawaii experienced its largest earthquake in more than a decade. Some 2,000 cubic kilometers of the southern slope of Kilauea volcano lurched toward the ocean, releasing the energy of a magnitude 5.7 shock. Part of that motion took place under an area where thousands of people stop every day to catch a glimpse of one of the island’s most spectacular lava flows. Yet when the earthquake struck, no one noticed--not even seismologists. How could such a notable event be overlooked?
[More]Nobel Prize-winning physicist Frank Wilczek and Scientific American editor George Musser talk about the Large Hadron Collider, the most powerful particle accelerator ever built, which went online this week. Plus, we'll test your knowledge about some recent science in the news. Web sites mentioned in this episode include www.frankwilczek.com
www.youtube.com/watch?v=j50ZssEojtM
[More]Nobel Prize-winning physicist Frank Wilczek and Scientific American editor George Musser talk about the Large Hadron Collider, the most powerful particle accelerator ever built, which went online this week. Plus, we'll test your knowledge about some recent science in the news. Web sites mentioned in this episode include www.frankwilczek.com
www.youtube.com/watch?v=j50ZssEojtM
[More]A new study of a stellar explosion visible from halfway across the universe finds that the blast had an unusual structure that researchers heretofore had never observed.
Gamma-ray burst GRB 080319B was already on record as the brightest stellar explosion ever recorded.
[More]A new study of a stellar explosion visible from halfway across the universe finds that the blast had an unusual structure that researchers heretofore had never observed.
Gamma-ray burst GRB 080319B was already on record as the brightest stellar explosion ever recorded.
[More]The detection of extra dimensions beyond the familiar four--the three dimensions of space and one of time--would be among the most earth-shattering discoveries in the history of physics. Now scientists at the Fermi National Accelerator Laboratory in Batavia, Ill., are designing a new experiment that would investigate tantalizing hints that extra dimensions may indeed exist.
Last year researchers involved in Fermilab’s MiniBooNE study, which detects elusive subatomic particles called neutrinos, announced that they had found a surprising anomaly. Neutrinos, which have no charge and very little mass, form out of nuclear reactions and particle decays. They come in three types, called flavors--electron, muon and tau--and oscillate wildly from one flavor to another as they travel along. While observing a beam of muon neutrinos generated by one of Fermilab’s particle accelerators, the MiniBooNE researchers found that an unexpectedly high number of the particles in the low-energy range (below 475 million electron volts) had transformed into electron neutrinos. After a year of analysis, the investigators have failed to come up with a conventional explanation for this so-called low-energy excess. The mystery has focused attention on an intriguing and very unconventional hypothesis: a fourth kind of neutrino may be bouncing in and out of extra dimensions.
[More]The detection of extra dimensions beyond the familiar four--the three dimensions of space and one of time--would be among the most earth-shattering discoveries in the history of physics. Now scientists at the Fermi National Accelerator Laboratory in Batavia, Ill., are designing a new experiment that would investigate tantalizing hints that extra dimensions may indeed exist.
Last year researchers involved in Fermilab’s MiniBooNE study, which detects elusive subatomic particles called neutrinos, announced that they had found a surprising anomaly. Neutrinos, which have no charge and very little mass, form out of nuclear reactions and particle decays. They come in three types, called flavors--electron, muon and tau--and oscillate wildly from one flavor to another as they travel along. While observing a beam of muon neutrinos generated by one of Fermilab’s particle accelerators, the MiniBooNE researchers found that an unexpectedly high number of the particles in the low-energy range (below 475 million electron volts) had transformed into electron neutrinos. After a year of analysis, the investigators have failed to come up with a conventional explanation for this so-called low-energy excess. The mystery has focused attention on an intriguing and very unconventional hypothesis: a fourth kind of neutrino may be bouncing in and out of extra dimensions.
[More]GAMING THE VOTE: WHY ELECTIONS AREN’T FAIR (AND WHAT WE CAN DO ABOUT IT)by William Poundstone. Hill and Wang, 2008
[More]GAMING THE VOTE: WHY ELECTIONS AREN’T FAIR (AND WHAT WE CAN DO ABOUT IT)by William Poundstone. Hill and Wang, 2008
[More]The future looks bright--maybe too bright. The sun is slowly expanding and brightening, and over the next few billion years it will eventually desiccate Earth, leaving it hot, brown and uninhabitable. About 7.6 billion years from now, the sun will reach its maximum size as a red giant: its surface will extend beyond Earth’s orbit today by 20 percent and will shine 3,000 times brighter. In its final stage, the sun will collapse into a white dwarf.
Although scientists agree on the sun’s future, they disagree about what will happen to Earth. Since 1924, when British mathematician James Jeans first considered Earth’s fate during the sun’s red giant phase, a bevy of scientists have reached oscillating conclusions. In some scenarios, our planet escapes vaporization; in the latest analyses, however, it does not.
[More]The future looks bright--maybe too bright. The sun is slowly expanding and brightening, and over the next few billion years it will eventually desiccate Earth, leaving it hot, brown and uninhabitable. About 7.6 billion years from now, the sun will reach its maximum size as a red giant: its surface will extend beyond Earth’s orbit today by 20 percent and will shine 3,000 times brighter. In its final stage, the sun will collapse into a white dwarf.
Although scientists agree on the sun’s future, they disagree about what will happen to Earth. Since 1924, when British mathematician James Jeans first considered Earth’s fate during the sun’s red giant phase, a bevy of scientists have reached oscillating conclusions. In some scenarios, our planet escapes vaporization; in the latest analyses, however, it does not.
[More]To unlock new secrets of the universe, Stephanie Majewski has to brush up on her French. The 27-year-old particle physicist is part of an international collaboration working on ATLAS, one of two experiments the size of small apartment buildings that will soon come online near Geneva, Switzerland. [More]
To unlock new secrets of the universe, Stephanie Majewski has to brush up on her French. The 27-year-old particle physicist is part of an international collaboration working on ATLAS, one of two experiments the size of small apartment buildings that will soon come online near Geneva, Switzerland. [More]
When physicists petitioned the U.S. Department of Energy (DoE) in the early 1980s to build a particle accelerator that would recreate the fiery conditions of the big bang, they picked a name worthy of its magnitude. The Superconducting Super Collider (SSC) located south of Dallas, Tex., would have outshined even the Large Hadron Collider, which after 14 years and $8 billion is about to start shooting particles around its 17-mile (27-kilometer) beam pipe on the Franco-Swiss border.
Slamming protons and antiprotons together at 40 tera-electron volts (40 trillion eV), the SSC would have put out more than enough energy to create the elusive Higgs boson, sometimes called the "God particle," which gives other particles their mass. (The less powerful LHC now has the honor of hunting the Higgs.) But escalating costs prompted Congress to cut the SSC's funding in 1993 before its components were even assembled.
[More]When physicists petitioned the U.S. Department of Energy (DoE) in the early 1980s to build a particle accelerator that would recreate the fiery conditions of the big bang, they picked a name worthy of its magnitude. The Superconducting Super Collider (SSC) located south of Dallas, Tex., would have outshined even the Large Hadron Collider, which after 14 years and $8 billion is about to start shooting particles around its 17-mile (27-kilometer) beam pipe on the Franco-Swiss border.
Slamming protons and antiprotons together at 40 tera-electron volts (40 trillion eV), the SSC would have put out more than enough energy to create the elusive Higgs boson, sometimes called the "God particle," which gives other particles their mass. (The less powerful LHC now has the honor of hunting the Higgs.) But escalating costs prompted Congress to cut the SSC's funding in 1993 before its components were even assembled.
[More]When the Large Hadron Collider (LHC) begins smashing protons together this fall inside its 17-mile- (27-kilometer-) circumference underground particle racetrack near Geneva, Switzerland, it will usher in a new era not only of physics but also of computing.
Before the year is out, the LHC is projected to begin pumping out a tsunami of raw data equivalent to one DVD (five gigabytes) every five seconds. Its annual output of 15 petabytes (15 million gigabytes) will soon dwarf that of any other scientific experiment in history.
[More]When the Large Hadron Collider (LHC) begins smashing protons together this fall inside its 17-mile- (27-kilometer-) circumference underground particle racetrack near Geneva, Switzerland, it will usher in a new era not only of physics but also of computing.
Before the year is out, the LHC is projected to begin pumping out a tsunami of raw data equivalent to one DVD (five gigabytes) every five seconds. Its annual output of 15 petabytes (15 million gigabytes) will soon dwarf that of any other scientific experiment in history.
[More]Researchers are closing in on ironclad evidence for the black hole believed to lurk at the center of our Milky Way galaxy. [More]
Researchers are closing in on ironclad evidence for the black hole believed to lurk at the center of our Milky Way galaxy. [More]
If you ever swim or paddle upstream, you will notice two things. First, a river's speed varies a lot. Second, those variations should cause you to pull harder when you hit rapidly flowing water. If you don't, you will simply make no progress. This puzzle replaces your muscles with a motor, but still asks you to figure out how to trade off energy for time. [More]
If you ever swim or paddle upstream, you will notice two things. First, a river's speed varies a lot. Second, those variations should cause you to pull harder when you hit rapidly flowing water. If you don't, you will simply make no progress. This puzzle replaces your muscles with a motor, but still asks you to figure out how to trade off energy for time. [More]
Within hours of his demise in 1955, Albert Einstein’s brain was salvaged, sliced into 240 pieces and stored in jars for safekeeping. Since then, researchers have weighed, measured and otherwise inspected these biological specimens of genius in hopes of uncovering clues to Einstein’s spectacular intellect.
Their cerebral explorations are part of a century-long effort to uncover the neural basis of high intelligence or, in children, giftedness. Traditionally, 2 to 5 percent of kids qualify as gifted, with the top 2 percent scoring above 130 on an intelligence quotient (IQ) test. (The statistical average is 100. See the box on the opposite page.) A high IQ increases the probability of success in various academic areas. Children who are good at reading, writing or math also tend to be facile at the other two areas and to grow into adults who are skilled at diverse intellectual tasks [see “Solving the IQ Puzzle,” by James R. Flynn; Scientific American Mind, October/November 2007].
[More]Within hours of his demise in 1955, Albert Einstein’s brain was salvaged, sliced into 240 pieces and stored in jars for safekeeping. Since then, researchers have weighed, measured and otherwise inspected these biological specimens of genius in hopes of uncovering clues to Einstein’s spectacular intellect.
Their cerebral explorations are part of a century-long effort to uncover the neural basis of high intelligence or, in children, giftedness. Traditionally, 2 to 5 percent of kids qualify as gifted, with the top 2 percent scoring above 130 on an intelligence quotient (IQ) test. (The statistical average is 100. See the box on the opposite page.) A high IQ increases the probability of success in various academic areas. Children who are good at reading, writing or math also tend to be facile at the other two areas and to grow into adults who are skilled at diverse intellectual tasks [see “Solving the IQ Puzzle,” by James R. Flynn; Scientific American Mind, October/November 2007].
[More]The steady rise of digital cameras has prompted the rapid growth of a new industry: instant photographic developing. A shutterbug brings her camera’s memory stick to a store, inserts it into a kiosk, selects the photographs she wants, and moments later prints drop into a chute. The machines seem to be everywhere. “In five years the number of digital kiosks has skyrocketed to 85,000 worldwide,” says Charles S. Christ, Jr., thermal systems director at Eastman Kodak in Rochester, N.Y.
The printers use a “dry” processing technique known as thermal dye transfer (as opposed to the traditional “wet” process of bathing exposed film in liquid chemicals). As the photographic paper scrolls past a print head, tiny resistors aligned in a row each heat up to specific temperatures, transferring minute amounts of yellow, magenta or cyan dye from a ribbon onto the paper. Together the dots form color pixels.
[More]The steady rise of digital cameras has prompted the rapid growth of a new industry: instant photographic developing. A shutterbug brings her camera’s memory stick to a store, inserts it into a kiosk, selects the photographs she wants, and moments later prints drop into a chute. The machines seem to be everywhere. “In five years the number of digital kiosks has skyrocketed to 85,000 worldwide,” says Charles S. Christ, Jr., thermal systems director at Eastman Kodak in Rochester, N.Y.
The printers use a “dry” processing technique known as thermal dye transfer (as opposed to the traditional “wet” process of bathing exposed film in liquid chemicals). As the photographic paper scrolls past a print head, tiny resistors aligned in a row each heat up to specific temperatures, transferring minute amounts of yellow, magenta or cyan dye from a ribbon onto the paper. Together the dots form color pixels.
[More]NewsHydrogen Power on the Cheap--Or, at Least, Cheaper [More]
NewsHydrogen Power on the Cheap--Or, at Least, Cheaper [More]