Mysterious dark matter could be shining with its own private kind of light. This "dark radiation" would be invisible to us, but could still have visible effects.
Astronomers usually assume that dark matter particles barely interact with each other.
Lotty Ackerman and colleagues at Caltech in Pasadena decided to test this assumption by supposing there is a force between dark matter particles that behaves in the same way as the electromagnetic force. That would imply a new form of radiation that is only accessible to dark matter.
Their calculations showed that it could have as much as 1% of the strength of the electromagnetic force and not conflict with any observations.
If the force is close to this strength, its effects might be detectable, as it should affect how dark matter clumps together.
Science & Technology
In a twist on nontraditional uses of ultrasound, a group of neuroscientists at Arizona State University has developed pulsed ultrasound techniques that can remotely stimulate brain circuit activity.
Their findings, published in the Oct. 29 issue of the journal Public Library of Science (PLoS) One, provide insights into how low-power ultrasound can be harnessed for the noninvasive neurostimulation of brain circuits and offers the potential for new treatments of brain disorders and disease.
While it might be hard to imagine the day where doctors could treat post traumatic stress disorders, traumatic brain injury and even Alzheimer's disease with the flip of a switch, most of us have in fact experienced some of ultrasound's numerous applications in our daily lives. For example, ultrasound has been used in fetal and other diagnostic medical imaging, ultrasonic teeth cleaning, physiotherapies, or surgical ablation. Ultrasound also provides a multitude of other non-medical uses, including pharmaceutical manufacturing, food processing, nondestructive materials testing, sonar, communications, oceanography and acoustic mapping.
Their findings, published in the Oct. 29 issue of the journal Public Library of Science (PLoS) One, provide insights into how low-power ultrasound can be harnessed for the noninvasive neurostimulation of brain circuits and offers the potential for new treatments of brain disorders and disease.
While it might be hard to imagine the day where doctors could treat post traumatic stress disorders, traumatic brain injury and even Alzheimer's disease with the flip of a switch, most of us have in fact experienced some of ultrasound's numerous applications in our daily lives. For example, ultrasound has been used in fetal and other diagnostic medical imaging, ultrasonic teeth cleaning, physiotherapies, or surgical ablation. Ultrasound also provides a multitude of other non-medical uses, including pharmaceutical manufacturing, food processing, nondestructive materials testing, sonar, communications, oceanography and acoustic mapping.
During the time it takes you to read this article, something will happen high overhead that until recently many scientists didn't believe in. A magnetic portal will open, linking Earth to the sun 93 million miles away. Tons of high-energy particles may flow through the opening before it closes again, around the time you reach the end of the page.
"It's called a flux transfer event or 'FTE,'" says space physicist David Sibeck of the Goddard Space Flight Center. "Ten years ago I was pretty sure they didn't exist, but now the evidence is incontrovertible."
Indeed, today Sibeck is telling an international assembly of space physicists at the 2008 Plasma Workshop in Huntsville, Alabama, that FTEs are not just common, but possibly twice as common as anyone had ever imagined.
"It's called a flux transfer event or 'FTE,'" says space physicist David Sibeck of the Goddard Space Flight Center. "Ten years ago I was pretty sure they didn't exist, but now the evidence is incontrovertible."
© Science@NASA
An artist's concept of Earth's magnetic field connecting to the sun's -- a.k.a. a "flux transfer event" -- with a spacecraft on hand to measure particles and fields.
An artist's concept of Earth's magnetic field connecting to the sun's -- a.k.a. a "flux transfer event" -- with a spacecraft on hand to measure particles and fields.
Indeed, today Sibeck is telling an international assembly of space physicists at the 2008 Plasma Workshop in Huntsville, Alabama, that FTEs are not just common, but possibly twice as common as anyone had ever imagined.
More than a year ago, in July 2007, International Space Station astronauts threw an obsolete, refrigerator-sized ammonia reservoir overboard. Ever since, the 1400-lb piece of space junk has been circling Earth in a decaying orbit--and now it is about to reenter.
If predictions are correct, the "Early Ammonia Servicer" (EAS for short) will turn into a brilliant fireball as it disintegrates in Earth's atmosphere during the early hours of Monday, Nov. 3rd. Uncertainties in the exact reentry time are so great (plus or minus 15 hours at the time of this alert) that it is impossible to pinpoint where the fireball will appear. At the moment, every continent except Antarctica has some favorable ground tracks.
If predictions are correct, the "Early Ammonia Servicer" (EAS for short) will turn into a brilliant fireball as it disintegrates in Earth's atmosphere during the early hours of Monday, Nov. 3rd. Uncertainties in the exact reentry time are so great (plus or minus 15 hours at the time of this alert) that it is impossible to pinpoint where the fireball will appear. At the moment, every continent except Antarctica has some favorable ground tracks.
The sabertooth cat (Smilodon fatalis), one of the most iconic extinct mammal species, was likely to be a social animal, living and hunting like lions today, according to new scientific research. The species is famous for its extremely long canine teeth, which reached up to seven inches in length and extended below the lower jaw.
Instead of relying on the bones and teeth of the sabertooths to make their findings, scientists from UCLA and the Zoological Society of London concluded that the sabertooth cat was social by using a novel technique: They compared numbers of present-day carnivores competing for kills in Africa with those of mainly extinct species found in a North American fossil deposit.
The research is published in the current issue of the Royal Society's journal Biology Letters (Oct. 28). Co-authors also included scientists from South Africa's Tshwane University of Technology and University of Pretoria.
Instead of relying on the bones and teeth of the sabertooths to make their findings, scientists from UCLA and the Zoological Society of London concluded that the sabertooth cat was social by using a novel technique: They compared numbers of present-day carnivores competing for kills in Africa with those of mainly extinct species found in a North American fossil deposit.
© Mauricio Antón
A reconstructed scene in the Pleistocene of western North America, showing a group of sabertooth cats of the species Smilodon fatalis, with several adults and cubs.
A reconstructed scene in the Pleistocene of western North America, showing a group of sabertooth cats of the species Smilodon fatalis, with several adults and cubs.
The research is published in the current issue of the Royal Society's journal Biology Letters (Oct. 28). Co-authors also included scientists from South Africa's Tshwane University of Technology and University of Pretoria.
Meteorites that are among the oldest rocks ever found have provided new clues about the conditions that existed at the beginning of the solar system, solving a longstanding mystery and overturning some accepted ideas about the way planets form.
The ancient meteorites, like disk drives salvaged from an ancient computer, still contain magnetic records about the very early history of planets, according to research by MIT planetary scientist Benjamin P. Weiss.
Weiss, the Victor P. Starr Career Development Assistant Professor of Planetary Sciences in the Department of Earth, Atmospheric and Planetary Sciences, and his five co-authors examined pieces of three meteorites called angrites, which are among the most ancient rocks known. The results of their study are being published in Science on Oct. 31.
The ancient meteorites, like disk drives salvaged from an ancient computer, still contain magnetic records about the very early history of planets, according to research by MIT planetary scientist Benjamin P. Weiss.
© Maria Zucolotto (Museu Nacional; Brasil)
A picture of the first discovered (and therefore eponymous) angrite "Angra dos Reis"; which was observed to fall from the sky in 1869 near the town of Angra dos Reis in Brazil. The black; shiny face was produced from melting of the meteorite's surface during passage through Earth's atmosphere. Scale bar is in centimeters.
A picture of the first discovered (and therefore eponymous) angrite "Angra dos Reis"; which was observed to fall from the sky in 1869 near the town of Angra dos Reis in Brazil. The black; shiny face was produced from melting of the meteorite's surface during passage through Earth's atmosphere. Scale bar is in centimeters.
Weiss, the Victor P. Starr Career Development Assistant Professor of Planetary Sciences in the Department of Earth, Atmospheric and Planetary Sciences, and his five co-authors examined pieces of three meteorites called angrites, which are among the most ancient rocks known. The results of their study are being published in Science on Oct. 31.
The Phoenicians, enigmatic people from the eastern shores of the Mediterranean, stamped their mark on maritime history, and now research has revealed that they also left a lasting genetic imprint.
Scientists reported Thursday that as many as 1 in 17 men living today on the coasts of North Africa and southern Europe may have a Phoenician direct male-line ancestor.
These men were found to retain identifiable genetic signatures from the nearly 1,000 years the Phoenicians were a dominant seafaring commercial power in the Mediterranean basin, until their conquest by Rome in the 2nd century B.C.
Scientists reported Thursday that as many as 1 in 17 men living today on the coasts of North Africa and southern Europe may have a Phoenician direct male-line ancestor.
These men were found to retain identifiable genetic signatures from the nearly 1,000 years the Phoenicians were a dominant seafaring commercial power in the Mediterranean basin, until their conquest by Rome in the 2nd century B.C.
Inside your laptop is a small accelerometer chip, there to protect the delicate moving parts of your hard disk from sudden jolts.
It turns out that the same chip is a pretty good earthquake sensor, too - especially if the signals from lots of them are compared, in order to filter out more mundane sources of laptop vibrations, such as typing.
It's an approach that is starting to gain acceptance. The project Quake Catcher Network (QCN), already has about 1500 laptops connected in a network that has detected several tremors, including a magnitude 5.4 quake in Los Angeles in July. Led by Elizabeth Cochran at the University of California, Riverside, and Jesse Lawrence at Stanford University, QCN uses the same BOINC platform for volunteer computing that projects like SETI@home rely on.
It turns out that the same chip is a pretty good earthquake sensor, too - especially if the signals from lots of them are compared, in order to filter out more mundane sources of laptop vibrations, such as typing.
It's an approach that is starting to gain acceptance. The project Quake Catcher Network (QCN), already has about 1500 laptops connected in a network that has detected several tremors, including a magnitude 5.4 quake in Los Angeles in July. Led by Elizabeth Cochran at the University of California, Riverside, and Jesse Lawrence at Stanford University, QCN uses the same BOINC platform for volunteer computing that projects like SETI@home rely on.
A 5,000-year-old mummy displays a genetic signature no longer found in Europe, according to its complete mitochondrial DNA sequence.
Scientists are on the hunt for evidence of antimatter - matter's arch nemesis - left over from the very early Universe. New results using data from NASA's Chandra X-ray Observatory and Compton Gamma Ray Observatory suggest the search may have just become even more difficult.
Antimatter is made up of elementary particles, each of which has the same mass as their corresponding matter counterparts --protons, neutrons and electrons -- but the opposite charges and magnetic properties. When matter and antimatter particles collide, they annihilate each other and produce energy according to Einstein's famous equation, E=mc2.
Antimatter is made up of elementary particles, each of which has the same mass as their corresponding matter counterparts --protons, neutrons and electrons -- but the opposite charges and magnetic properties. When matter and antimatter particles collide, they annihilate each other and produce energy according to Einstein's famous equation, E=mc2.
© X-ray: NASA/CXC/CfA/M.Markevitch et al. Optical: NASA/STScI; Magellan/U.Arizona/D.Clowe et al.
This view of the Bullet Cluster is a combination of X-rays from Chandra (red) and optical data from the Hubble and Magellan telescopes (yellow). Scientists have examined this system with Chandra and Compton to look for evidence of antimatter that may be found in X-ray and gamma ray emission. The results did not reveal the signature for antimatter, meaning that if it is there, antimatter is less than 3 parts per million in this system.
This view of the Bullet Cluster is a combination of X-rays from Chandra (red) and optical data from the Hubble and Magellan telescopes (yellow). Scientists have examined this system with Chandra and Compton to look for evidence of antimatter that may be found in X-ray and gamma ray emission. The results did not reveal the signature for antimatter, meaning that if it is there, antimatter is less than 3 parts per million in this system.
