New York - More than 400 years after Danish astronomer Tycho Brahe challenged established wisdom about the heavens by analyzing a strange new light in the sky, scientists say they've finally nailed down just what he saw.
It's no big surprise. Scientists have known the light came from a supernova, a huge star explosion. But what kind of supernova?
A new study confirms that, as expected, it was the common kind that involves the thermonuclear explosion of a white dwarf star with a nearby companion.
Science & Technology
Scientists from the California Institute of Technology have, for the first time, created an array of nanowires that are superconducting at relatively high temperatures. This work, published recently in Nano Letters, could lead to the incorporation of superconducting nanowires into emerging nanotechnologies.
Researchers around the world have been working to create superconducting nanowires, but few studies have investigated the feasibility of nanowires made of high-critical-temperature (high-Tc) superconducting materials and, prior to this work, no such nanowires had been produced.
Researchers around the world have been working to create superconducting nanowires, but few studies have investigated the feasibility of nanowires made of high-critical-temperature (high-Tc) superconducting materials and, prior to this work, no such nanowires had been produced.
Astronomers have uncovered strong evidence that brown dwarfs form like stars. Using the Smithsonian's Submillimeter Array (SMA), they detected molecules of carbon monoxide shooting outward from the object known as ISO-Oph 102. Such molecular outflows typically are seen coming from young stars or protostars. However, this object has an estimated mass of 60 Jupiters, meaning it is too small to be a star. Astronomers have classified it as a brown dwarf.
The mystery of what kind of star self-destructed to create the supernova observed by Danish astronomer Tycho Brahe in 1572 has been solved at last. A stellar ember called a white dwarf exploded after gorging on material stolen from its neighbour.
Previous observations had hinted at such a scenario, called a type Ia supernova. But the evidence was not strong enough to rule out other possible causes of death, such as the gravitational collapse of a massive star's core.
Now, a team led by Oliver Krause at the Max Planck Institute for Astronomy in Heidelberg, Germany, has spotted telltale signs of a type Ia supernova using the powerful 8.2-metre Subaru telescope in Hawaii.
They studied "light echoes" from the centuries-old supernova - light from the original explosion that reflected off interstellar dust and then headed in our direction.
Previous observations had hinted at such a scenario, called a type Ia supernova. But the evidence was not strong enough to rule out other possible causes of death, such as the gravitational collapse of a massive star's core.
© Max Planck Institute for Astronomy/O Krause/NASA
Tycho's supernova left behind an expanding cloud of super-hot debris, which appears green and yellow in this composite X-ray and infrared image stitched together from data from the Spitzer and Chandra space observatories and the Calar Alto observatory in Spain.
Tycho's supernova left behind an expanding cloud of super-hot debris, which appears green and yellow in this composite X-ray and infrared image stitched together from data from the Spitzer and Chandra space observatories and the Calar Alto observatory in Spain.
Now, a team led by Oliver Krause at the Max Planck Institute for Astronomy in Heidelberg, Germany, has spotted telltale signs of a type Ia supernova using the powerful 8.2-metre Subaru telescope in Hawaii.
They studied "light echoes" from the centuries-old supernova - light from the original explosion that reflected off interstellar dust and then headed in our direction.
The sun's magnetic field may have a significant impact on weather and climatic parameters in Australia and other countries in the northern and southern hemispheres. According to a study in Geographical Research, the droughts are related to the solar magnetic phases and not the greenhouse effect.
The study uses data from 1876 to the present to examine the correlation between solar cycles and the extreme rainfall in Australia.
It finds that the Southern Oscillation Index (SOI) - the basic tool for forecasting variations in global and oceanic patterns - and rainfall fluctuations recorded over the last decade are similar to those in 1914 -1924.
The study uses data from 1876 to the present to examine the correlation between solar cycles and the extreme rainfall in Australia.
© iStockphoto
It finds that the Southern Oscillation Index (SOI) - the basic tool for forecasting variations in global and oceanic patterns - and rainfall fluctuations recorded over the last decade are similar to those in 1914 -1924.
Imagine a self-powering cell phone that never needs to be charged because it converts sound waves produced by the user into the energy it needs to keep running. It's not as far-fetched as it may seem thanks to the recent work of Tahir Cagin, a professor in the Artie McFerrin Department of Chemical Engineering at Texas A&M University.
Utilizing materials known in scientific circles as "piezoelectrics," Cagin, whose research focuses on nanotechnology, has made a significant discovery in the area of power harvesting - a field that aims to develop self-powered devices that do not require replaceable power supplies, such as batteries.
Utilizing materials known in scientific circles as "piezoelectrics," Cagin, whose research focuses on nanotechnology, has made a significant discovery in the area of power harvesting - a field that aims to develop self-powered devices that do not require replaceable power supplies, such as batteries.
A researcher at the University of Portsmouth has identified a new species of pterosaur, the largest of its kind to ever be found. It represents an entirely new genus of these flying reptiles that ruled the skies 115 million years ago.
The finding is significant because it originated in Brazil and is the only example of the Chaoyangopteridae, a group of toothless pterosaurs, to be found outside China and is the largest one ever discovered.
Mark Witton identified the creature from a partial skull fossil from which he was able to estimate that it would have had a five-metre wingspan - bigger than a family car - and would stand over one metre tall at the shoulder.
The finding is significant because it originated in Brazil and is the only example of the Chaoyangopteridae, a group of toothless pterosaurs, to be found outside China and is the largest one ever discovered.
© University of Portsmouth
Mark Witton's depiction of the new species Lacusovagus, meaning 'lake wanderer.'
Mark Witton's depiction of the new species Lacusovagus, meaning 'lake wanderer.'
Mark Witton identified the creature from a partial skull fossil from which he was able to estimate that it would have had a five-metre wingspan - bigger than a family car - and would stand over one metre tall at the shoulder.
Scientists studying a material that appeared to lose its ability to carry current with no resistance say new measurements reveal that the material is indeed a superconductor - but only in two dimensions. Equally surprising, this new form of 2-D superconductivity emerges at a higher temperature than ordinary 3-D superconductivity in other compositions of the same material.
The research, conducted in part at the U.S. Department of Energy's (DOE) Brookhaven National Laboratory, will appear in the November 2008 issue of Physical Review B, and is now available online.
"Our basic research goal is to understand why and how these materials act as superconductors," said Brookhaven physicist John Tranquada, who led the research. "The ultimate practical goal would be to use that understanding to develop improved bulk superconductors - ones that operate at temperatures warm enough to make them useful for real-world applications such as high-efficiency power lines."
© DOE/Brookhaven National Laboratory
Stripe order in the copper oxide planes involves both a modulation of the charge density (blue), detectable with x-ray diffraction, and a modulation of the arrangement of magnetic dipole moments (spin directions) on copper atoms (magenta arrows), detectable with neutron diffraction.
Stripe order in the copper oxide planes involves both a modulation of the charge density (blue), detectable with x-ray diffraction, and a modulation of the arrangement of magnetic dipole moments (spin directions) on copper atoms (magenta arrows), detectable with neutron diffraction.
The research, conducted in part at the U.S. Department of Energy's (DOE) Brookhaven National Laboratory, will appear in the November 2008 issue of Physical Review B, and is now available online.
"Our basic research goal is to understand why and how these materials act as superconductors," said Brookhaven physicist John Tranquada, who led the research. "The ultimate practical goal would be to use that understanding to develop improved bulk superconductors - ones that operate at temperatures warm enough to make them useful for real-world applications such as high-efficiency power lines."
Free wireless internet access for everyone in the US could soon become a reality, but it all depends on the outcome of a vote at the US agency charged with regulating telecommunications.
The current chairman of the Federal Communications Commission, Kevin Martin, is championing the proposal, which would see the winner of an auction of the currently public radio spectrum having to set some aside for free internet access.
Were that plan to become reality, it could bring the benefits of internet connectivity to groups currently being left behind by the broadband age and shake up the market for mobile wireless devices, like cellphones and laptops. The scheme faces several hurdles, however.
The current chairman of the Federal Communications Commission, Kevin Martin, is championing the proposal, which would see the winner of an auction of the currently public radio spectrum having to set some aside for free internet access.
Were that plan to become reality, it could bring the benefits of internet connectivity to groups currently being left behind by the broadband age and shake up the market for mobile wireless devices, like cellphones and laptops. The scheme faces several hurdles, however.
Stars: A journey through stellar birth, life and death by Raman Prinja, is a comprehensive look at the latest developments in our understanding of the birth, life and death of stars.
It features many colour images from NASA, the Hubble Space Telescope and the Spitzer Space Telescope.
© NASA, ESA, C R O'Dell (Vanderbilt University), M Meixner and P McCullough (STScI)
The Helix planetary nebula is constructed from matter ejected by a dying Sun-like star, almost 690 light-years away.
The Helix planetary nebula is constructed from matter ejected by a dying Sun-like star, almost 690 light-years away.
It features many colour images from NASA, the Hubble Space Telescope and the Spitzer Space Telescope.
