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Sunday, June 9, 2013

Mars Sample Return: Bringing the Red Planet to Earth



Meet the scientists planning the next step in Martian exploration.

A space probe crashes in the desert. Something deadly on board wipes out almost the entire population of a small town. The government instigates an emergency protocol and top scientists gather at a secret underground quarantine facility to contain this killer germ from outer space.

Will they be able to save the planet from disaster?

To find out, read Michael Crichton’s Andromeda Strain – an adventure with heroic scientists. This terrifying tale of alien microbes, bringing instantaneous death to (almost) every living creature they come into contact with, was published weeks before the first Apollo lunar landing. But Nasa had already predicted this worst-case scenario of bringing back material from another world.

On their return to Earth, the Apollo 11 astronauts were locked away in a converted Airstream caravan - the Mobile Quarantine Facility. Lunar rocks and soil were sealed in bags and only opened in airtight laboratories. Even the Apollo capsule was wiped with bleach to destroy any stray Moon bugs. In retrospect, these precautions look rather quaint and the whole rigmarole was abandoned after Apollo 14, when scientists concluded that the Moon was completely devoid of life.

But now, 40 years on, Nasa is dusting down those quarantine procedures for a new challenge: returning rocks from Mars.

A so-called Mars sample return mission is the next step in the exploration of the red planet, coming between the existing rover missions, such as Curiosity, and future human exploration. It may also, finally, answer one of the biggest questions about Mars: is there life?

“The Curiosity rover does not have the instruments to answer the ‘are we alone’ question by itself,” says David Beaty, chief scientist for Nasa’s Mars Exploration Directorate at the Jet Propulsion Laboratory in Pasadena, California. “All it can do is understand the environment. Testing for ‘is there evidence of life?’ requires another mission and the best way to do that is by collecting samples and returning them to Earth.”

Saturday, June 8, 2013

Human-Scale Invisibility Cloak Unveiled

Researchers demonstrate an invisibility cloak that can be scaled to almost any size and say it could be used to hide orbiting satellites

In the last decade or so, invisibility cloaks have captured the imagination of researchers and the public alike. The excitement is based on two advances.

The first is the idea of “transformation optics”–the ability to bend light around a region of space to make it look as if it weren’t there. The second is the creation of metamaterials, synthetic substances with optical properties unknown in nature that can be designed to achieve this goal.

One of the goals in this area is to create a Harry Potter-style cloak capable of hiding a human at all optical frequencies in all directions. A bonus would be the ability to make this device as big or small as required so that it can hide objects of any size.

Achieving all these features is currently impossible. There is always a compromise. The first cloak worked only at a single microwave frequency. More recent cloaks work over the entire a range of optical frequencies but can only hide tiny objects over a limited viewing angle.

Today, John Howell at the University of Rochester in New York, and Benjamin Howell, show how to make simple cloaks that hide huge objects over the entire optical spectrum, albeit with a significant compromise. One of their devices is big enough to cloak a person.

Martian Rock Another Clue to a Once Water-Rich Planet

A view from the Mars rover Opportunity. The rover sampled a rock containing abundances of elements like aluminum, calcium and magnesium, which adds to a portrait of a planet that was once a water-rich world with conditions amenable for life.

The discovery of what appears to be a clay-rich rock on Mars adds to the portrait of the planet as one that once — in its youth, more than three and a half billion years ago — was a water-rich world with conditions amenable for life, NASA scientists said Friday.

The rock in question, about the size of a person’s forearm, was examined by the Mars rover Opportunity, the older of the spacecraft still in operation on the planet. The newer rover, the Curosity, landed last August and has been hogging the headlines ever since; in a news conference on Friday, NASA officials proudly called attention to the fact that the Opportunity, launched nearly a decade ago, was still soldiering on with valuable field work.

The newly discovered rock, which scientists named Esperance, is one of the oldest rocks that the Opportunity has looked at during its nine and a half years on Mars. From the abundances of elements like aluminum, calcium and magnesium, the mission’s scientists concluded that the rock is very rich in clay minerals, which could have formed from copious water running over volcanic rocks.

“This is powerful evidence that water interacted with this rock and changed its chemistry, changed its mineralogy in a dramatic way,” said Steven W. Squyres, the principal investigator.

Tuesday, June 4, 2013

Invisibility cloaking in 'perfect' demonstration

The trick included developing a diamond-shaped
cloaking region - invisible only from one direction
Scientists have succeeded in "cloaking" an object perfectly for the first time, rendering a centimetre-scale cylinder invisible to microwaves.

Many "invisibility cloak" efforts have been demonstrated, but all have reflected some of the incident light, making the illusion incomplete.

A Nature Materials study has now shown how to pull off the trick flawlessly.

However, the illusion only works from one direction and would be difficult to achieve with visible light.

The idea of invisibility cloaking got its start in 2006 when John Pendry of Imperial College London and David Schurig and David Smith of Duke University laid out the theory of "transformation optics" in a paper in Science, demonstrating it for the first time using microwaves (much longer wavelengths than we can see) in another Science paper later that year.

The papers sparked a flurry of activity to move the work on to different wavelengths - namely those in which we see.

As the "Where's my cloak of invisibility?" article points out, the field has moved on considerably since then.

But no effort to date has been able to achieve the "perfect" cloaking that the theory originally described.

The structures that can pull off this extraordinary trick of the light are difficult to manufacture, and each attempt has made an approximation to the theoretical idea that results in reflections.

It's like the card people in Alice in Wonderland... If they turn on their sides you can't see them but they're obviously visible if you look from the other direction - Prof David Smith (Duke University)

So someone would not see a cloaked object but rather the scene behind it - however, the reflections from the cloak would make that scene appear somewhat darkened.

Buzz Aldrin Points Out Inaccuracies in "After Earth"

Nearly a week after its release, M. Night Shyamalan’s “After Earth” has garnered a wide range of critics, including Buzz Aldrin who, despite calling it a great family drama, criticized it as unrealistic. And while the retired astronaut could go after a myriad of points, his main point of contention is the noise. (Photo : Reuters)

Nearly a week after its release, M. Night Shyamalan’s “After Earth” has garnered a wide range of critics, including Buzz Aldrin who, despite calling it a great family drama, criticized it as unrealistic. And while the retired astronaut could go after a myriad of points, his main point of contention is the noise.

“There was a lot of noise,” he told the Associated Press. “In space, you don’t get that much noise.”

The second man to step on the surface of the Moon further explained that even with his fellow astronaut beside him during that historic experience, the two communicated via headsets because “noise doesn’t propagate in a vacuum.”

Study: Increased carbon dioxide may lead to greener deserts

But researchers warn that CO2 fertilization could also result in other environmental shifts.

Increased levels of atmospheric carbon dioxide may have contributed to a gradual greening of some desert regions over the past 30 years, a process that will continue, according to a new study. But the authors warn that this "CO2 fertilization effect" could also have consequences for native plants and the wildlife that depends on them.

The study, published May 15 in the journal Geophysical Research Letters, was conducted by researchers from the Commonwealth Scientific and Industrial Research Organization (CSIRO), Australian National University and the Australian Research Council Centre of Excellence for Climate System Science.

The researchers went into this project knowing that satellite data collected since the 1980s has shown a worldwide increase in green foliage. Scientists around the world have theorized that this may have been a result of increased levels of CO2, a theory this new study supports. The authors of this new study looked at desert areas on four continents — where increases in vegetation would be easier to see and quantify — and created a mathematical model to calculate how they might have been affected by CO2 fertilization. With those calculations in hand, they then compared their predications to satellite imagery data from 1982 to 2010.

Friday, May 31, 2013

Mars radiation fears won't deter Nasa: the will to explore will prevail

People become astronauts knowing it's a dangerous job, and measures can be taken to minimise their radiation exposure

Local magnetic fields may provide some radiation protection in particular regions on Mars, but astronauts' living modules will need to be buried. Image: Nasa
How safe would a mission to Mars really be? As well as embarking on trips lasting several years in cramped craft with no breakdown cover, future interplanetary explorers will need to accept that their bodies will be zapped by high-energy particles, raising their risk of contracting cancer and other ill effects of radiation.

On Earth, we're all exposed to natural radiation from a variety of sources, including brazil nuts, bananas, and invisible radon gas. We'd be exposed to much higher doses from extraterrestrial sources if the Earth wasn't so well protected. The planet's magnetic field is carved into a teardrop-shaped bubble – the magnetosphere — by the solar wind that blows from the Sun. Although it contains some regions of higher radiation, the magnetosphere's overall effect is to shield life on Earth, and astronauts in low Earth orbit, from the harshest effects of cosmic radiation. Earth's atmosphere provides an additional buffer against all but the most energetic of particles. Astronauts travelling outside the magnetosphere, however, have to rely on the shell of their spacecraft to protect them from danger.

Thursday, May 30, 2013

The Wow! Signal: Intercepted Alien Transmission?

SETI, the search for extraterrestrial intelligence, has seen astronomers scouring the sky for decades in hopes of receiving artificially generated radio signals sent by alien civilizations. But then, there’s a good chance we’ve already found just such a signal. And 1977 saw the most tantalizing glimpse ever.

Nicknamed the “Wow!” signal, this was a brief burst of radio waves detected by astronomer Jerry Ehman who was working on a SETI project at the Big Ear radio telescope, Ohio. The signal was, in fact, so remarkable that Ehman circled it on the computer printout, writing “Wow!” in the margin — and unintentionally giving the received radio signal the name under which it would become famous.

Despite a lot of effort, no identification has been found for the signal’s source, and no repeat signal has ever been found. It’s a complete mystery. The only conclusion that can be drawn is if the signal truly did originate in deep space, then it was either an astrophysical phenomenon of which we’ve never seen before, or it truly was an intercepted alien signal.

Wednesday, May 29, 2013

Do we need watches to tell us more than the time?

Big companies have been trying hard to make the long-awaited smartwatch "revolution" happen, so tick tock, what's taking so long?

Smartwatches are just not very smart when left to their own devices - they need to be connected to a smartphone for full functionality.

While the industry is growing quickly, nearly all still need a smartphone's Bluetooth connection to tell you much more than just telling the time.

What a smartwatch could potentially do, at least to thousands of children in the 80s, was typified by the wristwatch David Hasselhoff's character used in Knight Rider to control his car.

But the industry is still so new there are many different approaches.

Apple's smartwatch is rumoured to exist 
already... or not exist at all. Or exist 
sometime soon
"Smartwatches can already be split into three or four categories," says senior analyst Josh Flood, of ABI Research.

"There are notification watches - the really basic ones which just link to the phone, voice-capable smart watches which is a really cool idea and health and fitness smartwatches for heart rate and running."

Others see even greater potential.

"Through NFC [near field communication], could you transfer travel cards to the watch?" says Skooks Pong, vice president of Synapse, a company working with Nike to develop its FuelBand activity tracker/watch hybrid.

"I think the tipping point will happen at the back end of this year” - Josh Flood (ABI Research)

"Who knows where it will go but I would love to be at a point where I could walk into the store, tap my wrist and pay for whatever it is I'm buying."

Tuesday, May 28, 2013

'Smart skin' hope for touch sensor

Smart skin





Scientists have made a step forward in their ability to mimic the sense of touch.


A team from the US and China made an experimental array that can sense pressure in the same range as the human fingertip.

The advance could speed the development of smarter artificial skin capable of "feeling" activity on the surface.

The sensors, which are described in Science magazine, could also help give robots a more adaptive sense of touch.

Using bundles of vertical zinc oxide nanowires, the researchers built arrays consisting of about 8,000 transistors.

"This is a fundamentally new technology that allows us to control electronic devices directly using mechanical agitation" - Zhong Lin Wang (Georgia Institute of Technology)

Each of the transistors can independently produce an electronic signal when placed under mechanical strain.