Science & Technology


Comet's 'death by sun' captured for first time

The Solar Dynamics Observatory AIA imager (observing in extreme ultraviolet light) actually spotted a sun-grazing comet as it disintegrated over about a 15-minute period on July 6, something never observed before. The angle of the comet's orbit brought it across the front half of the sun. Given the intense heat and radiation, the comet simply evaporated away. The comet was probably a member of the Kreutz sun-grazer family.
Satellite witnesses a 'sun-grazer' hit heat and disintegrate in 15 minutes

The death of a comet that plunged into the sun was captured on camera this month for the first time in history, scientists say.

The comet met its fiery demise on July 6 when it zoomed in from behind the sun and melted into oblivion as it crashed into the star. NASA's Solar Dynamics Observatory (SDO), a satellite orbiting Earth that studies the sun, witnessed the comet's death-blow.

One of the SDO spacecraft's high-definition imagers "actually spotted a sun-grazing comet as it disintegrated over about a 15-minute period July 6, 2011, something never observed before," SDO officials said.

Comets have been spotted near the sun before, but last week's object was the first to be observed in real-time as it disappeared.

"Given the intense heat and radiation, the comet simply evaporated away completely," SDO officials said.


More Fun With the Gut Microbiota and the Brain (In Mice)

Everyone has been tweeting this new paper, and I have to say, it's a doozy. I don't recommend that many papers, as most are fairly painful to read (though many papers are full of interesting facts, they don't teach scientists how to write), but if you can get your hands on this one, please do so.

The Intestinal Microbiota Affect Central Levels of Brain-Derived Neurotropic Factor and Behavior in Mice

Let's dive in. Ooh, I like the first part:
The intestinal microbiota is a vast ecosystem that shapes a wide variety of host functions, both within and outside the gastrointestinal tract.
Y'all may recall my previous article in which we have evidence that your commensal beasties, which make up 90% of your cells, also control a mouse's brain (and possibly yours.) And something like this paper and this experimental design excite me more than the endocannabinoid/rat paper I wrote about yesterday. I don't doubt that we probably have endocannabinoid receptors for corn oil (which may be activated by all kinds of fats) in our guts, or ones for sweets in our mouths, I'm just not sure what it means when isolated in that way via the sham-feeding and with creepy rat chow liquid diets that immediately drain out and dribble onto the rat cage in a gross gut slurry. However, we do have to keep in mind that these are rodents who diverged from the family tree many many many millions of years ago...


New Brain Discovery May Help Prevent Relapses in Addicts

© Emma Vought
A new brain pathway has been identified that links a brain area involved in representing environments (hippocampus) to an area that processes reward (VTA). This is important, for example, because places where addicts previously sought or obtained drugs can cause them to crave drugs again and lead them to relapse. This circuit provides a target to manipulate to help break the addiction cycle.

What makes you crave a Big Mac when you see the golden arches? Or long for a beer when you see a cold one on TV? A single pathway in the brain is to blame, new research suggests, and putting the brakes on it could stop addicts from relapsing.

The pathway connects the hippocampus, the part of the brain that analyzes and interprets the environment around you (using the contextual information that comes in through your senses, such as seeing a beer on TV) with the ventral tegmental area, or VTA, which processes reward-driven behaviors (such as grabbing a beer from the refrigerator).

Reward-driven behaviors release the brain chemical dopamine. Such behaviors include sex and eating, which are very important in daily life. But some drugs release these dopamine "rewards" at higher levels than natural reactions do, the heart of addiction.

"One of the issues we know of in drug addition is that a simple re-exposure to the drug-using environment ... will often result in relapse," said study researcher Alice Luo of the National Institutes of Health, in Baltimore. "Hopefully we can short-circuit the actual circuit itself, so the link between the context and reward could be blunted."


First Study into GM Atlantic Salmon Mating Reveals Danger of Escape to Wild Gene Pool

© n/a
If genetically modified Atlantic salmon were to escape from captivity they could succeed in breeding and passing their genes into the wild, Canadian researchers have found. Their research, published in Evolutionary Applications, explores the potential reproductive implications of GM salmon as they are considered for commercial farming.

"The use of growth-enhancing transgenic technologies has long been of interest to the aquaculture industry and now genetically modified Atlantic salmon is one of the first species to be considered for commercial farming. Yet, little is known about the potential impact on wild salmon populations if the GM species were to escape captivity," said lead author Darek Moreau from the Memorial University of Newfoundland, Canada.

One of the key concerns about a transgene escape is the "Trojan gene effect", caused when a GM fish outcompetes or reproduces equally against wild rivals, however if the resulting offspring are genetically inferior this could lead a species towards eventual extinction. Until now there is no empirical research to demonstrate the ability of transgenic Atlantic salmon to breed naturally and infiltrate the wild gene pool.


Solar Wind Changes Atmospheric Pressure over South Korea

© Technology Review, MIT
Evidence is growing that interplanetary magnetic fields can have a significant influence on our weather.

Space weather is a topic of growing interest both to space scientists and researchers whose focus is more Earth bound. Solar physicists have long known that the Sun regularly sends powerful magnetic clouds our way.

When they strike, the damage can be extensive. The magnetic fields induce currents in railway tracks and power lines which can then bring down entire power networks.

But the influence of space weather on the terrestrial weather is less well understood. The solar wind, and the magnetic clouds that sometimes accompany it, contain huge amounts of energy. Much of this is absorbed or deflected by the Earth's magnetic field.

But from time to time, magnetic clouds can temporarily lower our defences. During these so-called Forbush Decreases, more particles from the solar wind can get through and dump their load in the upper atmosphere.

It stands to reason that such an injection of energy could change the weather. And there's certainly evidence that this can happen at high latitudes near the poles. But the rest of the planet seems better protected.


Light Traveled Faster in the Early Universe?

© The Daily Galaxy
A brilliant physicist João Magueijo asks the heretical question: What if the speed of light - now accepted as one of the unchanging foundations of modern physics - were not constant?

"A number of surprising observations made at the threshold of the 21st century have left cosmologists confused and other physicists in doubt over the reliability of cosmology," Magueijo says. "For instance it has been found that the cosmological expansion appears to be accelerating. This is contrary to common sense, as it implies that on large scales gravity is repulsive. Another upheaval resulted from the high redshift mapping of the fine structure constant. Evidence was found for a time dependence of this supposed constant of Nature. Yet another puzzle was the observation of rare very high energy cosmic rays. Standard kinematic calculations, based on special relativity, predict a cut off well below the observed energies, so this may perhaps represent the first experimental mishap of special relativity.

"These three surprises are not alone and prompt several questions. Is the Universe trying to tell us something radical about the foundations of physics?" he continues. "Or are astronomers merely trying to irritate the conservative physicist? It could well be that the strange observations emerging from the new cosmology are correct, and that they provide a unique window into dramatically novel physics. Is the Universe trying to give us a physics lesson?"

Magueijo, a 40-year old native of Portugal, puts forth the heretical idea that in the very early days of the universe light traveled faster - an idea that if proven could dethrone Einstein and forever change our understanding of the universe. He is a pioneer of the varying speed of light (VSL) theory of cosmology -an alternative to the more mainstream theory of cosmic inflation- which proposes that the speed of light in the early universe was of 60 orders of magnitude faster than its present value.


Evolved Stars Locked in Fatalistic Dance

© David A. Aguila
white dwarfs
Two white dwarfs have been discovered on the brink of a merger. In just 900,000 years, material will start to stream from one star to the other (as shown in this artist's conception), beginning the process that may end with a spectacular supernova explosion. Watching these stars fall in will allow astronomers to test Einstein's general theory of relativity as well as the origin of a special class of supernovae
White dwarfs are the burned-out cores of stars like our Sun. Astronomers have discovered a pair of white dwarfs spiraling into one another at breakneck speeds. Today, these white dwarfs are so near they make a complete orbit in just 13 minutes, but they are gradually slipping closer together. About 900,000 years from now - a blink of an eye in astronomical time - they will merge and possibly explode as a supernova. By watching the stars converge, scientists will test both Einstein's general theory of relativity and the origin of some peculiar supernovae.

The two white dwarfs are circling at a bracing speed of 370 miles per second (600 km/s), or 180 times faster than the fastest jet on Earth.


25 Tesla, world-record 'split magnet' makes its debut

© Florida State University
Interior parts for the split coil magnet were tested and retested to ensure the magnet’s structural integrity.
A custom-built, $2.5 million "split magnet" system with the potential to revolutionize scientific research in a variety of fields has made its debut at the National High Magnetic Field Laboratory at Florida State University.

The world-record magnet is operating at 25 tesla, easily besting the 17.5 tesla French record set in 1991 for this type of magnet. ("Tesla," named for early 20th-century inventor and engineer Nikola Tesla, is a measurement of the strength of a magnetic field.) In addition to being 43 percent more powerful than the previous world best, the new magnet also has 1,500 times as much space at its center, allowing room for more flexible, varied experiments.


Haiti Rock Is Surprising Remnant of Ancient Supercontinent

Unusual lavas in the Caribbean apparently originated from the lost, ancient supercontinent of Gondwana, scientists have found.

This discovery reveals that continental material can get dragged along the Earth's surface for more than a thousand miles and survive for more than a billion years, serving as cores around which islands and perhaps even continents might eventually grow.

Scientists investigated lavas from the Caribbean island of Hispaniola, home to Haiti on its western half and the Dominican Republic in the east. A better understanding of the history of this island "will be important for the modern tectonics of Hispaniola, especially Haiti, as the lavas were found in the general area of the fault system that caused the devastating earthquake in Haiti in 2010," said researcher George Kamenov, a geochemist at the University of Florida in Gainesville.


Near-Perfect Particle Measurement Achieved

© Dreamstime
An atom consists of a nucleus of protons and neutrons, with electrons orbiting around.
The mind-bending laws of quantum mechanics say we can't observe the smallest particles without affecting them. Physicists have now caused the smallest-ever disturbance while making a quantum measurement - in fact, almost the minimum thought to be possible.

This disturbance is called back-action, and it is one of the hallmarks of quantum mechanics, which governs the actions of the very small. It arises from the supposition that before a measurement is made, particles exist in a sort of limbo state, being neither here nor there while retaining the possibility of either.

Once an observer intervenes, the particle is forced to "choose" a state, to settle on one possibility, eliminating the other options. Thus, the state of the particle is altered by the act of measuring it.

"The atom changes because you are looking," explained physicist Peter Maunz of Duke University.