Astronomy Picture of the Day

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2008 June 7

June's Young Crescent Moon
Credit & Copyright: Miguel Claro

Explanation: Serene skyviews were enjoyed across planet Earth earlier this week with a young crescent Moon low in the western sky just after sunset. Recorded on June 4, this colorful example includes a quiet beach in the foreground with the city lights of Lisbon, Portugal, and the Sintra Mountains along the horizon. Posing between cloud banks, the Moon's slender, sunlit arc represents only about 1 percent of the full lunar disc. The rest of the Moon's nearside is faintly visible though, illuminated by Earthshine. A waxing crescent Moon should also create some lovely western skies at dusk this weekend. The bright star in the sky near tonight's (Saturday's) Moon will actually be the planet Mars. On Sunday the Moon will move closer to a pair of celestial beacons, bright star Regulus and Saturn.

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NASA Scientists Pioneer Method for Making Giant Lunar Telescopes

After Apollo 12 left lunar orbit this image of the Moon was taken from the command module on 11/24/69. Credit: NASA
> Print size resolution Scientists working at NASA’s Goddard Space Flight Center in Greenbelt, Md., have concocted an innovative recipe for giant telescope mirrors on the Moon. To make a mirror that dwarfs anything on Earth, just take a little bit of carbon, throw in some epoxy, and add lots of lunar dust.

"We could make huge telescopes on the moon relatively easily, and avoid the large expense of transporting a large mirror from Earth," says Peter Chen of NASA Goddard and the Catholic University of America, which is located in Washington, D.C. "Since most of the materials are already there in the form of dust, you don’t have to bring very much stuff with you, and that saves a ton of money."

Chen and his Goddard colleagues Douglas Rabin, Michael Van Steenberg, and Ron Oliversen are presenting their mirror-making technique in a poster at the 212th meeting of the American Astronomical Society in St. Louis, Mo. They will also describe their results in a press conference on Wednesday, June 4 at 9:30 a.m. CDT.

For years, Chen had been working with carbon-fiber composite materials to produce high-quality telescope mirrors. But Chen and his colleagues decided to try an experiment. They substituted carbon nanotubes (tiny tubular structures made of pure carbon) for the carbon-fiber composites. When they mixed small amounts of carbon nanotubes and epoxies (glue-like materials) with crushed rock that has the same composition and grain size as lunar dust, they discovered to their surprise that they had created a very strong material with the consistency of concrete. This material can be used instead of glass to make mirrors.

They next applied additional layers of epoxy and spun the material at room temperature. The result was a 12-inch-wide mirror blank with the parabolic shape of a telescope mirror. All of this was achieved with minimal effort and cost.

"After that, all we needed to do was coat the mirror blank with a small amount of aluminum, and voilà, we had a highly reflective telescope mirror," says Rabin. "Our method could be scaled-up on the moon, using the ubiquitous lunar dust, to create giant telescope mirrors up to 50 meters in diameter." Such an observatory would dwarf the largest optical telescope in the world right now: the 10.4-meter Gran Telescopio Canarias in the Canary Islands.

The capabilities of a 50-meter telescope on the Moon boggle the imagination, according to NASA. With a stable platform, and no atmosphere to absorb or blur starlight, the monster scope could record the spectra of extra solar terrestrial planets and detect atmospheric biomarkers such as ozone and methane. Two or more such telescopes spanning the surface of the Moon can work together to take direct images of Earth-like planets around nearby stars and look for brightness variations that come from oceans and continents. Among many other projects, it could make detailed observations of galaxies at various distances, to see how the universe evolved.

"Constructing giant telescopes provides a strong rationale for doing astronomy from the moon," says Chen. "We could also use this on-site composite material to build habitats for the astronauts, and mirrors to collect sunlight for solar-power farms."

Chen notes that his group achieved this breakthrough with only the support of small NASA internal seed funds. The carbon nanotubes were contributed by Dan Powell, Lead Nanotechnologist for NASA Goddard. Several amateur astronomers made key contributions by advising and making special epoxy formulations, helping with polishing experiments, and vacuum coating the 12-inch mirror.

Robert Naeye

Goddard Space Flight Center

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The Future Is Now? Pretty Soon, at Least

Before we get to Ray Kurzweil’s plan for upgrading the “suboptimal software” in your brain, let me pass on some of the cheery news he brought to the World Science Festival last week in New York.

Do you have trouble sticking to a diet? Have patience. Within 10 years, Dr. Kurzweil explained, there will be a drug that lets you eat whatever you want without gaining weight.

Worried about greenhouse gas emissions? Have faith. Solar power may look terribly uneconomical at the moment, but with the exponential progress being made in nanoengineering, Dr. Kurzweil calculates that it’ll be cost-competitive with fossil fuels in just five years, and that within 20 years all our energy will come from clean sources.

Are you depressed by the prospect of dying? Well, if you can hang on another 15 years, your life expectancy will keep rising every year faster than you’re aging. And then, before the century is even half over, you can be around for the Singularity, that revolutionary transition when humans and/or machines start evolving into immortal beings with ever-improving software.

At least that’s Dr. Kurzweil’s calculation. It may sound too good to be true, but even his critics acknowledge he’s not your ordinary sci-fi fantasist. He is a futurist with a track record and enough credibility for the National Academy of Engineering to publish his sunny forecast for solar energy.

He makes his predictions using what he calls the Law of Accelerating Returns, a concept he illustrated at the festival with a history of his own inventions for the blind. In 1976, when he pioneered a device that could scan books and read them aloud, it was the size of a washing machine.

Two decades ago he predicted that “early in the 21st century” blind people would be able to read anything anywhere using a handheld device. In 2002 he narrowed the arrival date to 2008. On Thursday night at the festival, he pulled out a new gadget the size of a cellphone, and when he pointed it at the brochure for the science festival, it had no trouble reading the text aloud.

This invention, Dr. Kurzweil said, was no harder to anticipate than some of the predictions he made in the late 1980s, like the explosive growth of the Internet in the 1990s and a computer chess champion by 1998. (He was off by a year — Deep Blue’s chess victory came in 1997.)

“Certain aspects of technology follow amazingly predictable trajectories,” he said, and showed a graph of computing power starting with the first electromechanical machines more than a century ago. At first the machines’ power doubled every three years; then in midcentury the doubling came every two years (the rate that inspired Moore’s Law); now it takes only about a year.

Dr. Kurzweil has other graphs showing a century of exponential growth in the number of patents issued, the spread of telephones, the money spent on education. One graph of technological changes goes back millions of years, starting with stone tools and accelerating through the development of agriculture, writing, the Industrial Revolution and computers. (For details, see nytimes.com/tierneylab.)

Now, he sees biology, medicine, energy and other fields being revolutionized by information technology. His graphs already show the beginning of exponential progress in nanotechnology, in the ease of gene sequencing, in the resolution of brain scans. With these new tools, he says, by the 2020s we’ll be adding computers to our brains and building machines as smart as ourselves.

This serene confidence is not shared by neuroscientists like Vilayanur S. Ramachandran, who discussed future brains with Dr. Kurzweil at the festival. It might be possible to create a thinking, empathetic machine, Dr. Ramachandran said, but it might prove too difficult to reverse-engineer the brain’s circuitry because it evolved so haphazardly.

“My colleague Francis Crick used to say that God is a hacker, not an engineer,” Dr. Ramachandran said. “You can do reverse engineering, but you can’t do reverse hacking.”

Dr. Kurzweil’s predictions come under intense scrutiny in the engineering magazine IEEE Spectrum, which devotes its current issue to the Singularity. Some of the experts writing in the issue endorse Dr. Kurzweil’s belief that conscious, intelligent beings can be created, but most think it will take more than a few decades.

He is accustomed to this sort of pessimism and readily acknowledges how complicated the brain is. But if experts in neurology and artificial intelligence (or solar energy or medicine) don’t buy his optimistic predictions, he says, that’s because exponential upward curves are so deceptively gradual at first.

“Scientists imagine they’ll keep working at the present pace,” he told me after his speech. “They make linear extrapolations from the past. When it took years to sequence the first 1 percent of the human genome, they worried they’d never finish, but they were right on schedule for an exponential curve. If you reach 1 percent and keep doubling your growth every year, you’ll hit 100 percent in just seven years.”

Dr. Kurzweil is so confident in these curves that he has made a $10,000 bet with Mitch Kapor, the creator of Lotus software. By 2029, Dr. Kurzweil wagers, a computer will pass the Turing Test by carrying on a conversation that is indistinguishable from a human’s.

I’m not as confident those graphs are going to hold up for fields besides computer science, so I’d be leery of betting on a date. But if I had to take sides in the 2029 wager, I’d put my money on Dr. Kurzweil. He could be right once again about a revolution coming sooner than expected. And I’d hate to bet against the chance to be around for this one.

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Behind the Scenes: Cloaking Device Concept Moves Beyond Theory

This Behind the Scenes article was provided to LiveScience in partnership with the National Science Foundation.

Applied mathematician Graeme Milton dreams up new materials, develops mathematical formulas to describe them and leaves it to others to construct and demonstrate their novelties and usefulness in a laboratory.

While many of his theoretical musings are published in peer-reviewed journals, his research on a superlens with the ability to hide or “cloak” an object is too similar to cloaking devices portrayed in Star Trek and Harry Potter to stay buried in the annals of academia.

The concept of a superlens came originally from Sir John Pendry in 2000 — although Milton and his colleagues Nicolae Nicorovici and Ross McPhedran conducted closely related studies back in 1994 — and the concept has been studied extensively. Yet no one had realized the cloaking properties until they were discovered through the research by Milton’s team.

The concept of a superlens cloak is a long way from a workable device, but the integrity of the mathematical concept has sent some experimentalists into the laboratory to try and turn the theory into reality. So far, the groups working in this area are not ready to publish papers, but they’ve accomplished enough to keep trying.

“We’re along way off from the Star Trek device but some of the experimental results achieved so far are surprising and exciting,” Milton noted.

Milton pursues his research at the University of Utah where the math department has some of the best scientists in the nation for studying the mathematics of new materials.

While colleagues consider Milton among “the best in the world” with the mathematics of materials, he was not always so highly ranked. In fact, Milton, who was born in Sydney, Australia, came close to failing his sophomore year at Sydney University because he spent so much time reading about advanced subjects such as quantum mechanics and general relativity he failed to attend his regular classes, and eventually dropped out of school to spend a year hitchhiking through New Zealand.

He later returned to the university to buckle down and earn his bachelor’s and master’s degrees in physics, followed by a doctorate in physics at Cornell University. His love of the outdoors led him to accept the job in Utah – he does some of his best thinking while skiing, mountain biking, swimming and road biking.

The superlens theorized by Milton and Nicorovici cloaks a nearby object by making light behave in an unusual way. Instead of having a positive refractive index that makes light bend in the same way as it does when passing from air into a medium like glass or water, the superlens has a negative refractive index that in essence causes light to reverse and travel backwards. When an object is placed next to the superlens, the light bouncing off the object is canceled out by the light reflecting off the superlens, rendering the object invisible. Milton said the phenomenon, theorized by Milton and Nicorovici and confirmed by computer, is somewhat analogous to the noise cancellation headphones passengers wear on airplanes.

“At this point, experiments would be considered successful if they worked with a single frequency of light and cloaked a few specks of dust, and the object cloaked would need to be much smaller than the superlens,” said Milton. In spite of the challenge, a group of scientists is currently working to demonstrate the proof of principle. “They’ve made some progress, but they want to do some more work before they put their results in a paper,” he added.

Potential early uses for a cloaking device are varied. While stealth military devices are an obvious option, one approach is in medicine where the concept would allow certain electronic instruments to be used despite the presence of strong electromagnetic fields, such as those produced by hospital brain scanners. Milton and other researchers have also carried out related work that might prove capable of guiding the elastic shock waves of earthquakes around buildings.

While practical applications are fun to speculate about, mathematicians may appreciate the new math presented by the concept just as much.

“The findings will lead to a better understanding of partial differential equations, which will lead to a better understanding the propagation of sound, light, fluid and turbulence,” Milton said. The new math will also help scientists better understand the new field of metamaterials – a family of new materials with properties not seen in naturally occurring materials. “Existing laws don’t adequately describe materials with exotic microstructures that are associated with some metamaterials.”

Devising new materials is how Milton and his colleagues came across the superlens in the first place. A metamaterial’s properties are dictated by its internal structure rather than by its composition. His job requires him to discover or design new geometric structures and then develop mathematical formulas to prove their properties. He was working in his home country of Australia on a composite material composed of arrays of coated cylinders when he realized the cylinders could focus light in an unconventional way. That discovery eventually led to his mathematical model for the superlens cloak.

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Why Men Have Breasts

TV personality Maria Menounos and Harrison Ford during an interview on the beach at the 61st International film festival in Cannes, southern France, on Friday, May 16, 2008. Credit: AP Photo/Matt Sayles

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The June 9 issue of "People" magazine has a disturbing photograph of actor Harrison Ford.

There he is, the hunk aka Han Solo and Indiana Jones, walking along the beach at the Cannes Film Festival wearing a man-bra.

I swear.

Ford is dressed in a pair of black pants and a slate blue T-shirt that shows off his buff mid section. But that T-shirt also reveals the shadow of what has to be a manzeer, in the parlance of Seinfeld.

And he needs it.

Mr. Ford, for all his aging manliness, has a set of man boobs that many women would envy. Which brings us to the age-old question that anthropologists have been answering for centuries: Why do men have breasts and nipples?

They have them because men start out as women.

As much as men hate to hear this, the human fetal blueprint is initially female. We all begin as a ball of cells that quickly differentiates into various body parts. At five weeks of gestation, the fetus sports a neural tube that eventually becomes the spine, but other than that, we all look like a wad of chewing gum. Then at six weeks' gestation, the outlines of eyes, arms, legs and a face (and let's not mention the tail that also shows up for a while) appear.

It's not until about week six that the fetus also begins to take on the biological accoutrements of gender.

If the fetus has a Y chromosome, testosterone will turn the buds for sexual organs into testes. Once in operation, those testes will pump out even more testosterone and, voila, a penis appears.

Female fetuses aren’t swayed by testosterone and so they stick with the fallback blueprint that calls for ovaries and a vagina.

But the developmental secret here is that breasts and nipples are already in place before testosterone shows its hand and starts shaping cells into male organs.

In other words, men have breasts and nipples because they already had them before they became male.

But then why didn't evolution opt to remove those seemingly useless female parts?

Because evolution doesn’t simply wipe out unnecessary physical bits and pieces. Those parts have to be a burden, or be in the way of survival and reproduction for evolution to take notice. Since there's no real caloric cost to men having boobs, evolution has no impetus to erase them.

In fact, men's breasts are a good lesson in the higgledy-piggledy way that evolution works. Natural selection chooses for and against body parts, but there is no master plan that aims for the perfect creature. Men have boobs, women get facial hair, and we all stand in front of the mirror asking, "Why?"

Each person is, in fact, a Rube Goldberg sort of organism pieced together by biology and made up of good parts, bad parts and parts that are inconsequential.

But Mr. Ford should also know that his fans really don’t care about the manzeer. Believe me, even with the moobs (man boobs), any woman over 40 would be glad to have him for the night, even if it meant throwing a towel over his chest.

In fact, wearing a manzeer is probably not hurting Mr. Ford's potential reproductive success at all. I bet there are lots of women of child-bearing age, those who watched "Star Wars" as babies, or those seeing Indiana Jones for the first time this summer, who would also be happy to close their eyes for a moment with what we gals know in our heart of hearts is a real man.

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New 'super-paper' is stronger than cast iron

Punching your way out of a paper bag could become a lot harder, thanks to the development of a new kind of paper that is stronger than cast iron.

The new paper could be used to reinforce conventional paper, produce extra-strong sticky tape or help create tough synthetic replacements for biological tissues, says Lars Berglund from the Swedish Royal Institute of Technology in Stockholm, Sweden.

Despite its great strength, Berglund's "nanopaper" is produced from a biological material found in conventional paper: cellulose. This long sugar molecule is a principal component of plant cell walls and is the most common organic compound on Earth.

Wood is typically about half cellulose, mixed with other structural compounds.

Support network

In plant cell walls individual cellulose molecules bind together to produce fibres around 20 nanometres in diameter, 5000 times thinner than a human hair. These fibres form tough networks that provide the cell walls with structural support.

"Cellulose nanofibres are the main reinforcement in all plant structures and are characterised by nanoscale dimensions, high strength and toughness," Beglund told New Scientist.

Cellulose is extracted from wood to make paper, is the basis of cellophane, and has also recently been used by materials scientists developing novel plastic materials. But they have used it only as a cheap filler material, ignoring its mechanical properties.

However, the mechanical processes used to pulp wood and process it into paper damage the individual cellulose fibres, greatly reducing their strength. So Berglund and colleagues have developed a gentler process that preserves the fibres' strength.

Tough as iron

The new method involves breaking down wood pulp with enzymes and then fragmenting it using a mechanical beater. The shear forces produced cause the cellulose to gently disintegrate into its component fibres.

The end result is undamaged cellulose fibres suspended in water. When the water is drained away Berglund found that the fibres join together into networks held by hydrogen bonds, forming flat sheets of "nanopaper".

Mechanical testing shows it has a tensile strength of 214 megapascals, making it stronger than cast iron (130 MPa) and almost as strong as structural steel (250 MPa).

Normal paper has a tensile strength less than 1 MPa. The tests used strips 40 millimetres long by 5mm wide and about 50 micrometres thick.

Dissipating stress

The secret to the nanopaper's performance is not only the strength of the undamaged cellulose fibres, but also they way they are arranged into networks. Although strongly bound together, they are still able to slip and slide over each other to dissipate strains and stresses.

The individual cellulose fibres are also much smaller than in conventional paper. "A regular paper network has fibres 30 micrometres in diameter, here we are at a scale three orders of magnitude smaller," says Beglund. "The material [has] very small defects compared with a conventional paper network."

"This [work] shows quite clearly the potential for cellulose nanofibres to provide a basis for reinforcement," says Stephen Eichhorn, a polymer scientist at the University of Manchester, UK.

Journal Reference: Biomacromolecules (DOI: 10.1021/bm800038n)

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Test offers a genetic excuse for laziness

A simple test could soon identify whether difficulty in getting out of bed in the morning is down to genes or pure laziness.

	Scientists say that some of us are night owls by nature

Scientists say that some of us are night owls by nature - late to rise and late to go to bed - while others are larks, genetically programmed to wake early.

They have developed a swab test that can identify a person's natural tendency to wake early or late from cells collected from inside the cheek.

Discussions are under way with Boots to develop an over-the-counter version.

It raises the possibility of workers who are repeatedly late being asked by their bosses to take a test to show whether or not they have a genetic excuse. The test was demonstrated by researchers from the School of Medicine at Swansea University on visitors to the Cheltenham Science Festival.

"The novel technique we have developed at Swansea is entirely non-invasive, so we can use it at a public event," explained Dr Sarah Forbes-Robertson, who worked on the project with Dr Adeel Siddiqui and Alison Baird. "Previously you needed to take blood sample. Our technique allows us to get a useable sample just by swabbing the inside of an individual's cheek."

The test can reveal the activity of a number of different genes that control the "natural" pattern of wake and sleep - the circadian rhythm.

One gene, known as Per2, is especially active at around 4am, and is associated with sleeping. Another, known as REV-ERB, seems to work in opposition to Per2, having its peak activity at around 4pm, and is thought to be associated with wakefulness.

Of her own patterns, Dr Forbes Robertson said: "My peak of Per2 - the 'sleep' gene - is at 6am rather than at the usual 4am. So I really do have a genetic excuse for not being able to manage early morning meetings. To get a full and accurate picture of someone's natural circadian rhythm you would need to take samples four hourly over a full day and night, and also look at all the genes involved.

"But by taking samples at 4pm and 5pm to assess the activity of the REV-ERB gene, we will be able to see if patterns of peak gene expression are shifted forwards or back in time from the norm of 4pm. If your peak is earlier than 4pm it would indicate that you are a natural early bird, if you peak later than 5pm then you are more of a night owl."

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Edison, Make Way for the L.E.D.’s

If you’re looking for the latest advancements in incandescent light bulb technology, one place you don’t want to go is to a lighting trade show. I learned that in about five minutes last week, while touring the aisles of Lightfair, the lighting industry’s big convention, held this year in Las Vegas.

In case you didn’t know it, Thomas Edison’s invention, in use for more than 100 years to illuminate virtually everything, is quickly heading for the exits. What will eventually take its place is the light-emitting diode (L.E.D.) bulb, made up of tiny light sources the size of a head of a pin that use a fraction of a regular light bulb’s electricity, produce little heat, and last for tens of thousands of hours of use.

This is not some comic book dream. The exhibits at Lightfair were filled with new L.E.D. products, many shipping now: standard-type room lights, under-counter lights, commercial spotlights, garden lights and huge L.E.D. displays designed to light the Empire State Building.

I saw L.E.D.’s controlled by a cell phone. Forgot to turn on your porch light? Just dial in a command.

L.E.D.’s are not widely used today because of their high cost: An L.E.D. bulb can run as high as $90. Even if they would save money in the long run, few people are willing to spend that much up front.

But costs will come down, and when they do, expect to see the end of what is in essence an interim technology: the compact fluorescent bulb. Fluorescents, while using much less power than incandescent light bulbs, are sometimes too bulky, often can’t be dimmed and produce light that is less pleasing than incandescents.

L.E.D.’s, on the other hand, can produce literally millions of colors, which you will be able to witness yourself at the end of this year, when Philips, the Dutch electronics giant, introduces its $199 Living Colors product into the U.S. market.

Living Colors is Philips’ L.E.D. Trojan horse, an electronic lava lamp that uses L.E.D.’s to project a palette of 16 million colors against a wall. Operated with a remote control, you change the projected color by touching a point on the iPod-like color wheel, then push other buttons to decrease the brightness or alter the color’s saturation.

The company has already sold 250,000 Living Color products in Europe; in the U.S., it will offer the regular model plus a $79 mini version that offers a limited palette and no remote.

I’ve been playing with one for several weeks, and after some initial resistance to its corniness, I’ve taken a liking to it. Every night, I set the color of one wall of our bedroom to a different hue, hopefully matching our moods. It’s a nice change from standard yellow light and gives some added dimension to the space.

Philips points out that you can set up a chain of Living Color units around a room and control them all with a single remote. For me, that’s just a bit over the top. I don’t fancy turning my house into a Las Vegas facade.

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Super-sensitive and small: New MIT detector uses nanotubes to sense deadly gases

Using carbon nanotubes, MIT chemical engineers have built the most sensitive electronic detector yet for sensing deadly gases such as the nerve agent sarin.

The technology, which could also detect mustard gas, ammonia and VX nerve agents, has potential to be used as a low-cost, low-energy device that could be carried in a pocket or deployed inside a building to monitor hazardous chemicals.

"We think this could be applied to a variety of environmental and security applications," said Michael Strano, the Charles and Hilda Roddey Associate Professor of Chemical Engineering and senior author of a paper describing the work published this week in the online edition of Angewandte Chemie.

Strano's sensor has exhibited record sensitivity to molecules mimicking organophosphate nerve toxins such as sarin: It can detect minute quantities as low as 1 femtomole (1 billion molecules), roughly equivalent to a concentration of 25 parts per trillion. "There's nothing that even comes close," he said.

Sarin, which killed 12 people in a 1995 terrorist attack on the Tokyo subway, can kill at very low concentrations (parts per million) after 10 minutes, so highly sensitive detection is imperative to save lives. The new detector is far more sensitive than needed to detect lethal doses.

To build their super-sensitive detector, Strano and his team used an array of carbon nanotubes aligned across microelectrodes. Each tube consists of a single-layer lattice of carbon atoms, rolled into a long cylinder with a diameter about 1/50,000 of the width of a human hair, which acts as a molecular wire.

The nanotube sensors require very little power--about 0.0003 watts. One sensor could run essentially forever on a regular battery. "It's something that could sit in the corner of a room and you could just forget about it," Strano said.

When a particular gas molecule binds to the carbon nanotube, the tube's electrical conductivity changes. Each gas affects conductivity differently, so gases can be identified by measuring the conductivity change after binding.

The researchers achieved new levels of sensitivity by coupling the nanotubes with a miniature gas-chromatography column etched onto a silicon chip smaller than a penny. The column rapidly separates different gases before feeding them into the nanotubes.

The new MIT sensor is also the first nanotube sensor that is passively reversible at this level of sensitivity. To achieve this, the team needed to decrease how strongly the nanotube sensor binds different gas molecules on its surface, allowing the sensor to detect a series of gas exposures in rapid succession.

Using a newly described chemistry outlined in a separate paper published in January in the Journal of the American Chemical Society, Strano and co-workers showed that this can be done by coating the nanotubes with amine-type molecules, which donate an extra pair of electrons to the nanotubes.

The coating allows gas molecules to bind to nanotubes but detach a few milliseconds later, allowing another molecule from the column to move in. With a network of these reversible sensors, a gas could be tracked as it spreads through a large area.

The lead author of the paper is Chang Young Lee, a graduate student in chemical engineering. Richa Sharma, another MIT graduate student in chemical engineering, is also an author of the paper. Adarsh Radadia and Richard Masel at the University of Illinois at Urbana-Champaign developed the microcolumn technology.

The work was funded by the Department of Homeland Security under contract to the Federal Aviation Administration and MIT's Institute of Soldier Nanotechnology. Characterization facilities used for this work were supported by the Department of Energy. Microcolumn and detector development was funded in part by the Defense Advanced Research Projects Agency.

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It's official: Caribbean monk seal is extinct

Only seal species to vanish due to human impacts; two other species at risk

	The Caribbean monk seal, also known as the West Indian seal, will be remembered only by drawings. On Friday, the U.S. declared it extinct. View related photos

After five years of futile efforts to find or confirm sightings of any Caribbean monk seals — even just one — the U.S. government on Friday announced that the species is officially extinct and the only seal to vanish due to human causes.

"Humans left the Caribbean monk seal population unsustainable after overhunting them," Kyle Baker, a biologist for the National Marine Fisheries Service, said in a statement. "Unfortunately, this led to their demise and labels the species as the only seal to go extinct from human causes."

A Caribbean monk seal — the only subtropical seal native to the Caribbean Sea and Gulf of Mexico — had not been seen for more than 50 years. The last confirmed sighting was in 1952 at Seranilla Bank, between Jamaica and the Yucatan Peninsula.

The United States listed the species as endangered in 1967. The fisheries service will now have the species removed from the list.

"Caribbean monk seals were first discovered during Columbus’s second voyage in 1494, when eight seals were killed for meat," the fisheries service noted. "Following European colonization from the 1700s to 1900s, the seals were exploited intensively for their blubber, and to a lesser extent for food, scientific study and zoological collection. Blubber was processed into oil and used for lubrication, coating the bottom of boats, and as lamp and cooking oil. Seal skins were sought to make trunk linings, articles of clothing, straps and bags."

Hawaiian, Mediterranean species at risk
Just two other monk seal species remain: Hawaiian and Mediterranean monk seals, both of which are endangered and at risk of extinction. Populations have fallen to below 1,200 and 500 individuals, respectively, the fisheries service stated.

"Worldwide, populations of the two remaining monk seal species are declining," said Baker. "We hope we’ve learned from the extinction of Caribbean monk seals, and can provide stronger protection for their Hawaiian and Mediterranean relatives."

The Hawaiian population is declining at a rate of about four percent per year, with challenges "such as lack of food sources for young seals, entanglement in marine debris, predation by sharks, and loss of haul-out and pupping beaches due to erosion," the service said.

Gordon Olayvar / Hawaii Dept. of Land and Natural Resources via AP These two Hawaiian monk seals were found washed up on Oahu's Makua Beach on May 27, 2007. The one trapped in fishing lines died from drowning. The other survived, following the dead animal's carcass to shore and barking loudly at people as they approached to disentangle the body.

"The Hawaiian monk seal is a treasure to preserve for future generations," said NMFS biologist Bud Antonelis. The "fisheries service has developed a monk seal recovery plan, but we need continued support from organizations and the public if we are to have a chance at saving it from extinction. Time is running out."

"The fate of the Caribbean monk seal is a wake-up call for us to act quickly to protect other endangered monk seal populations. We must learn from our mistakes," Vicki Cornish of Ocean Conservancy echoed in a separate statement. "We must act now to reduce threats to existing monk seal populations before it's too late. These animals are important to the balance and health of the ocean — we can't afford to wait."

Other species of marine mammals that have gone extinct in modern times include the Atlantic gray whale (1700s or 1800s) and stellar sea cow (late 1700s), presumably due to overhunting by whalers, the fisheries service stated.

Climate connection
The Ocean Conservancy said some of the threats, especially erosion and debris, are tied to the El Nino weather pattern and rising sea levels, which in turn is tied to global warming.

"El Nino events, which cause storms similar to those expected to occur with increasing frequency as a result of climate change, drive marine debris closer to monk seal beaches and nearshore waters," it added. "Seal pups play with trash, which can lead to entanglement and eventual death. Increased numbers of Hawaiian monk seals have been found entangled in marine debris after El Nino events."

Entanglement happens even in "one of the best-protected ocean places in the United States," the conservation group said, referring to the Northwestern Hawaiian Islands National Monument created by President Bush in 2006.

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5 Homemade Chemical Free Bug Repellents That Work

Not only can insects be a nuisance in your garden, but they can ruin a perfect picnic or hike. Here are a few totally green, home remedy suggestions to repel insects without using toxic chemicals.

#1 Pepper Spray

This works great for ants and other small pests.

• Boil 2 or 3 cups of water.
• Add about ½ to 2/3 cup of chopped hot pepper. Let marinate for a few minutes.
• Run the mixture thru a sieve to remove the peppers.
• Put the liquid in a squirt bottle and use when necessary.
• Be careful not to spray directly on foliage.

#2 Minty Soap Spray

This is great for ants.

• Mix 2 tbsp of Dr. Bonners mint soap with a gallon of water.
• Spray directly on ants.

This will also work to ward off other pests on foliage however be care when you spray it directly on your plants. It has been known to burn some plants if too much is applied.

#3 Pure Vanilla Extract

Dab a little on you wrists, neck and behind the ears. Many insects don’t like the smell.

#4 Chem-Free Bug Off Mist

• Mix witch hazel with a few drops of tea tree oil, lavender oil, or peppermint oil in a squirt bottle.
• Lightly mist your body.

You can also add one of these essential oils to an unscented organic lotion for a bug repelling moisturizer.

#5 Lavender Works Mosquito Miracles

Stop the bites!

• Rub a lavender flower behind your ears, wrists and neck.
• Not only will you smell great but mosquitoes will leave you alone.

Go Greener!

We don’t need to use spray’s and harmful chemicals to keep pests away. There are plenty of natural, chemical free solutions to control bugs this summer. Go greener, our planet will thank you!

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Something's Shaking in Antarctica

Scientists have discovered massive, slow-motion "ice quakes" trembling twice a day through the West Antarctic Ice Sheet, an Alaska-sized swath of Antarctica. Detective work has traced the source of the shaking to the Whillans Ice Stream, a glacier 100 kilometers across and 1 kilometer thick, which flows from the ice sheet's interior.

It may seem strange that magnitude-7 quakes went unnoticed for so long--a temblor of similar size leveled entire towns and killed at least 15,000 in Turkey in 1999--but people standing on the Whillans Ice Stream never notice the shaking. "The reason that it doesn't rattle the whole continent is that it's a very slow event," says Sridhar Anandakrishnan, a glaciologist at Pennsylvania State University in State College, who made the discovery along with Douglas Wiens, a seismologist at Washington University in St. Louis, Missouri. Normal earthquakes release their energy over a few seconds, but the Whillans's shaking unfolds over 20 minutes.

Wiens first noticed the ice quakes 3 years ago as he analyzed data from 43 seismic sensors across Antarctica. Hoping for faint signals that would help him pinpoint previously unknown faults, he was instead greeted by booming vibrations from the same spot in West Antarctica. Wiens then looked at seismic data collected in 2004, the same year that Anandakrishnan had deployed 16 GPS sensors on the Whillans Ice Stream that tracked the ice's movement every 10 seconds. Most glaciers edge forward continuously, but the Whillans was already known to behave bizarrely: It sits still most of the time, then surges more than a half-meter forward twice per day as ocean tides lift and lower a slab of floating ice that extends from the end of the glacier onto the Ross Sea, just off the coast of Antarctica. By combining the GPS and seismic data, the researchers saw that the ice quakes and glacial surges synchronized perfectly in time, suggesting that the shaking was caused by the ice grinding over a rough spot in the rock below, they report 5 June in Nature.

Finding the causes of ice quakes--which also occur in Greenland--could lead to better understanding glacial movement and improved models of how glaciers will respond to climate change, says Robert Bindschadler, a glaciologist at NASA Goddard Space Flight Center in Greenbelt, Maryland, who first reported the twice-daily surges of the Whillans Ice Stream in 2003. "What has come from these discoveries is a realization that glaciers have other modes of behavior than we have thought of previously," says Göran Ekström, a seismologist with Columbia University.

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