Science & TechnologyS


Sun

Coolest Brown Dwarf Spotted by Earth-bound Telescopes

Brown Dwarf
© ESO/L. CalçadaArtist's impression of the binary brown dwarf system CFBDSIR 1458+10.

Astronomers have found the coldest known star - a brown dwarf in a double system about as hot as a cup of tea. The discovery blurs the line between small cold stars and large hot planets. The star, CFBDSIR 1458+10B, is the dimmer member of the binary system, about 75 light-years from Earth.

Lead study author Michael Liu, from the University of Hawaii's Institute for Astronomy, said finding ever-cooler stars "has been one of the big themes of this field since it's existed in the last 15 years." Brown dwarfs are essentially failed stars; they lack enough mass for gravity to trigger the nuclear reactions that make stars shine. Liu said while the idea of a brown dwarf is many decades old, they were first confirmed in 1995, the same year the first gas giants were detected around other stars.

"Residing at the extremes of low mass, luminosity and temperature, brown dwarfs serve as laboratories for understanding gas-giant extrasolar planets as well as the faint end of the star formation process," write the authors in the new paper, in the Astrophysical Journal. "The coolest known brown dwarfs, the T dwarfs, have temperatures (~600 - 1400 K) ... that are more akin to Jupiter than any star."

Liu said cool brown dwarfs are exciting to find partly because they make great proxies for studying the mysteries of water cloud formation in the atmospheres of gas giants. Such clouds are believed to form when temperatures dip below 400 to 450 K.

Radar

Study examines how brain corrects perceptual errors

Image
© Unknown
New research provides the first evidence that sensory recalibration - the brain's automatic correcting of errors in our sensory or perceptual systems - can occur instantly.

"Until recently, neuroscientists thought of sensory recalibration as a mechanism that is primarily used for coping with long-term changes, such as growth during development, brain injury or stroke," said Ladan Shams, a UCLA assistant professor of psychology and an expert on perception and cognitive neuroscience. "It appeared that extensive time, and thus many repetitions of error, were needed for mechanisms of recalibration to kick in. However, our findings indicate we don't need weeks, days, or even minutes or seconds to adapt. To some degree, we adapt instantaneously.

"If recalibration can occur in milliseconds, as we now think, then we can adapt even to transient changes in the environment and in our bodies."

Info

Seeing Through The Cracks

Japan
© Wikipedia

While rescue workers in Japan continue their search for missing persons amid the rubble in Sendai and beyond, geologists are sifting through seismic data and satellite images for hints to what caused one of the most catastrophic earthquakes in recorded history. For the past week, scientists around the world have posted charts and maps on blogs and websites to help describe the extent of the quake, and the vulnerabilities that possibly triggered the massive rupture.

So far, data have shown the quake may have redistributed the Earth's mass and moved the planet's axis, increasing its speed of rotation and shortening the day by a fraction of a second. There are also reports that a significant portion of Japan's eastern shoreline dropped off by several feet as a result of motion along a fault line further east where one tectonic plate slid under another. There are reports that the east coast of the island of Honshu may have also shifted to the east as a result of the quake. Scientists observed what may be farther-reaching effects, as the tremor may have also momentarily shifted the position of a large glacier in Antarctica.

Bradford Hager, Cecil and Ida Green Professor of Earth Sciences in the Department of Earth, Atmospheric and Planetary Sciences, says the outpouring of scientific analyses is thanks in part to Japan's extensive monitoring system - a network of thousands of sensors on land and sea that have continuously kept tabs on local seismic energy.

"It's incredible how instrumented this quake is," Hager says. "With a thousand GPS receivers, you can see there's a lot of detail. Having that data will enable us to understand and statistically forecast earthquakes in the future."

Info

The Importance of Being Magnetized

Magnetosphere_1
© NASAThe Earth's magnetosphere deflects some of the solar wind.

Our nearest planetary neighbors, Mars and Venus, have no oceans or lakes or rivers. Some researchers have speculated that they were blown dry by the solar wind, and that our Earth escaped this fate because its strong magnetic field deflects the wind. However, a debate has arisen over whether a magnetic field is any kind of shield at all.

The controversy stems from recent observations that show Mars and Venus are losing oxygen ions from their atmospheres into space at about the same rate as Earth. This came as something of a surprise, since only Earth has a strong dipolar magnetic field that can prevent solar wind particles from slamming into the upper atmosphere and directly stripping away ions.

"My opinion is that the magnetic shield hypothesis is unproven," says Robert Strangeway from UCLA. "There's nothing in the contemporary data to warrant invoking magnetic fields."

Each of the three planets is losing roughly a ton of atmosphere to space every hour. Some of this lost material was originally in the form of water, so this begs the question: how did the planets end up with vastly different quantities of water if they are all "leaking" to space at similar rates?

"The problem is in taking today's rates and trying to guess what was happening billions of years ago," says Janet Luhmann of the University of California, Berkeley. She believes Earth's magnetic field could have made the difference in the past when the solar wind was presumably stronger.

"People aren't putting all the cards on the table," Luhmann says. "We can't say that magnetic fields are unimportant from the current data."

Both Luhmann and Strangeway agree that sorting out what makes one planet wet while another is dry will require more data on how the atmospheric loss depends on the Sun's output.

Beaker

Superconductivity Near 20 Celsius

Superconductivity Approaches Room Temperature

Superconductors.ORG herein reports the observation of superconductivity near 20 C.

In eight magnetization tests a small amount of the compound (Tl5Pb2)Ba2MgCu10O17+ consistently produced sharp diamagnetic transitions (the Meissner effect) near 20 Celsius (see above graphic), and resistive transitions that appeared near 18.5C (see below right). These temperatures are believed accurate +/- 2 degrees.

superconds
© SuperconductorsResistance-v-temperature tests of this material were performed using a 4-point probe. Four significant bits of data resolution were necessary to resolve the 18.5C critical transition temperature (Tc) due to a low signal-to-noise ratio (S/N). A sharp transition appeared across just 1.5 uA of a 220 uA signal. This suggests a superconductive volume fraction less than 1% of the bulk.

This extraordinarily high Tc was achieved by engineering a theoretical D223 structure (where D=11 hex) that pushes the limit of the longest C-axis lattice that will superconduct, while simultaneously establishing near-optimum Pb-doping of the Tl-Cu-O blocking layers (see structure at left).

Info

Viscous Cycle: Quartz Is Key To Plate Tectonics

Quartz
© USGSQuartz may play a major role in the movements of continents, known as plate tectonics.

More than 40 years ago, pioneering tectonic geophysicist J. Tuzo Wilson published a paper in the journal Nature describing how ocean basins opened and closed along North America's eastern seaboard.

His observations, dubbed "The Wilson Tectonic Cycle," suggested the process occurred many times during Earth's long history, most recently causing the giant supercontinent Pangaea to split into today's seven continents.

Wilson's ideas were central to the so-called Plate Tectonic Revolution, the foundation of contemporary theories for processes underlying mountain-building and earthquakes.

Since his 1967 paper, additional studies have confirmed that large-scale deformation of continents repeatedly occurs in some regions but not others, though the reasons why remain poorly understood.

Now, new findings by Utah State University geophysicist Tony Lowry and colleague Marta Perez-Gussinye of Royal Holloway, University of London, shed surprising light on these restless rock cycles.

Robot

Go on, print me a bike! The technology that enables a computer to run off a full-working cycle

This bicycle is the first in the world to be created simply by printing it out on a computer, using groundbreaking new technology.

The fully-working cycle, which is made of nylon, is the result of an extraordinary project and is as strong as steel and aluminium but weighs 65 per cent less.

Scientists in Bristol designed the bike on a computer and sent it to a printer, which placed layers of melted nylon powder on top of each other to build-up the machine.
computer print bicycle
© SolentLet's ride: The fully-working cycle, which is made of nylon, is the result of an extraordinary project and is as strong as steel and aluminium but weighs 65 per cent less.

Star

Coming to a Sky Near You: The Realm of Galaxies

We live on a planet which orbits a star, and along with a hundred billion other stars, our Sun orbits the centre of our Milky Way galaxy. It doesn't just stop there; our galaxy is one of hundreds of billions of galaxies in our Universe that gravitationally clump together in groups or clusters.

Image
© NASAHubble Ultra-Deep Field
Throughout Spring in the northern hemisphere, astronomers and people interested in the night sky are going to be in for a galactic treat, as this is the time of year we can see the Coma/Virgo Super cluster or "Realm of Galaxies".

Galaxies are massive islands of stars, gas and dust in the Universe; they are where stars and planets are born and eventually die. Galaxies are cosmic factories of creation - where it all happens on a very grand scale. To give you an idea of size, it would take you roughly 100,000 years to travel across the disc of the Milky Way at the speed of light!

Saturn

Saturn's UFO moons: Bizarrely-shaped Pan and Atlas baffle scientists


Comment: If it's coming from an official space science organization, you can be pretty sure its "science" is bogus. Take the following article, for example, with our commentary embedded within.


They look more like flying-saucers than icy moons, but Pan and Atlas are two of Saturn's strangest satellites.

Scientists have long been puzzled by how the oddly-shaped moons, which are only 20miles across, came to be.


Comment: They are only strange because NASA and the ESA. have no clue how the solar system really works.


Researchers based at the European Space Agency now think they have some answers after studying several years worth of cosmic images.

Image
© unknownUFO? Pan is Saturn's most inner moon, as seen in this illustration. It orbits within the Encke Gap in the planet's A ring
They realised that 14 of Saturn's small moons had a very low density - about half that of water ice - and shapes that suggested they had grown out of the rings themselves.


Comment: Wow. James McCanney predicted "sweeper moons" in the gaps of Saturn's rings over thirty years go, before Pan was even discovered. It took ESA this long to realize this?


However, they would have needed a jump start as it is not gravitationally possible for small particles to fuse together within the rings.


Comment: Again, if they had read McCanney, they wouldn't be so hopelessly confused. Gravity is NOT the only force acting in our solar system. The "shepherd" or "sweeper" moons attract the material of the rings because the moons are discharging Saturn's electrical capacitor. The positively charged ions (including dust and gases) get pulled to the nucleus where they recombine with electrons, depositing a dust cloud around the moon. This explains the disc-like shape of Pan, which has cleared out the "Encke Gap" in Saturn's rings. Just look at this picture.


Therefore, each moon would have started with a massive core that was a leftover from the original collisions that caused the rings.

Nuke

Plutonium in troubled reactors, spent fuel pools

Image
© AP Photo/Tokyo Electric Power Co. via Kyodo NewsUnit 4 at Japan's crippled Fukushima Dai-ichi nuclear power plant in Okumamachi, Fukushima Prefecture. March 16, 2011
The fuel rods at all six reactors at the stricken Fukushima Dai-ichi complex contain plutonium - better known as fuel for nuclear weapons. While plutonium is more toxic than uranium, other radioactive elements leaking out are likely to be of greater danger to the general public.

Only six percent of the fuel rods at the plant's Unit 3 were a mixture of plutonium-239 and uranium-235 when first put into operation. The fuel in other reactors is only uranium, but even there, plutonium is created during the fission process.

This means the fuel in all of the stricken reactors and spent fuel pools contain plutonium.

Plutonium is indeed nasty stuff, especially damaging to lungs and kidneys. It is also less stable than uranium and can more easily spark a dangerous nuclear chain reaction.