Doubling down on Schrödinger's cat

Yale physicists have given Schrödinger's cat a second box to play in.

Yale physicists have given Schrödinger's famous cat a second box to play in, and the result may help further the quest for reliable quantum computing.

Schrödinger's cat is a well-known paradox that applies the concept of superposition in quantum physics to objects encountered in everyday life. The idea is that a cat is placed in a sealed box with a radioactive source and a poison that will be triggered if an atom of the radioactive substance decays. Quantum physics suggests that the cat is both alive and dead (a superposition of states), until someone opens the box and, in doing so, changes the quantum state.

This hypothetical experiment, envisioned by one of the founding fathers of quantum mechanics in 1935, has found vivid analogies in laboratories in recent years. Scientists can now place a wave-packet of light composed of hundreds of particles simultaneously in two distinctly different states. Each state corresponds to an ordinary (classical) form of light abundant in nature.

A team of Yale scientists created a more exotic type of Schrödinger's cat-like state that has been proposed for experiments for more than 20 years. This cat lives or dies in two boxes at once, which is a marriage of the idea of Schrödinger's cat and another central concept of quantum physics: entanglement. Entanglement allows a local observation to change the state of a distant object instantaneously. Einstein once called it "spooky action at a distance," and in this case it allows a cat state to be distributed in different spatial modes.

The Yale team built a device consisting of two, 3D microwave cavities and an additional monitoring port -- all connected by a superconducting, artificial atom. The "cat" is made of confined microwave light in both cavities.

"This cat is big and smart. It doesn't stay in one box because the quantum state is shared between the two cavities and cannot be described separately," said Chen Wang, a postdoctoral associate at Yale and first author of a study in the journal Science, describing the research. "One can also take an alternative view, where we have two small and simple Schrodinger's cats, one in each box, that are entangled."

The research also has potential applications in quantum computation. A quantum computer would be able to solve certain problems much faster than classical computers by exploiting superposition and entanglement. Yet one of the main problems in developing a reliable quantum computer is how to correct for errors without disturbing the information.

"It turns out 'cat' states are a very effective approach to storing quantum information redundantly, for implementation of quantum error correction. Generating a cat in two boxes is the first step towards logical operation between two quantum bits in an error-correctible manner," said co-author Robert Schoelkopf, Sterling Professor of Applied Physics and Physics, and director of the Yale Quantum Institute.

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Antarctic fossils reveal creatures weren't safer in the south during dinosaur extinction

A study of more than 6,000 marine fossils from the Antarctic shows that the mass extinction event that killed the dinosaurs was sudden and just as deadly to life in the polar regions.

Previously, scientists had thought that creatures living in the southernmost regions of the planet would have been in a less perilous position during the mass extinction event than those elsewhere on Earth.

The research, published today in the journal Nature Communications, involved a six-year process of identifying more than 6,000 marine fossils ranging in age from 69- to 65-million-years-old that were excavated by scientists from the University of Leeds and the British Antarctic Survey on Seymour Island in the Antarctic Peninsula.

This is one of the largest collections of marine fossils of this age anywhere in the world. It includes a wide range of species, from small snails and clams that lived on the sea floor, to large and unusual creatures that swam in the surface waters of the ocean. These include the ammonite Diplomoceras, a distant relative of modern squid and octopus, with a paperclip-shaped shell that could grow as large as 2 metres, and giant marine reptiles such as Mosasaurus, as featured in the film Jurassic World.

With the marine fossils grouped by age, the collection shows a dramatic 65-70% reduction in the number of species living in the Antarctic 66 million years ago -- coinciding exactly with the time when the dinosaurs and many other groups of organisms worldwide became extinct at the end of the Cretaceous Period.

James Witts, a PhD student in the University's School of Earth and Environment and lead author of the new research paper said: "Our research essentially shows that one day everything was fine -- the Antarctic had a thriving and diverse marine community -- and the next, it wasn't. Clearly, a very sudden and catastrophic event had occurred on Earth.

"This is the strongest evidence from fossils that the main driver of this extinction event was the after-effects of a huge asteroid impact, rather than a slower decline caused by natural changes to the climate or by severe volcanism stressing global environments."

The study is the first to suggest that the mass extinction event was just as rapid and severe in the polar regions as elsewhere in the world.

Previously, scientists had thought that organisms living near the Poles were far enough away from the cause of the extinction to be badly affected -- whether this was an asteroid impact in the Gulf of Mexico, where a giant buried impact crater is found today, or extreme volcanism in the Deccan volcanic province in India. Furthermore, it had been proposed that animals and plants in the polar regions would have been more resilient to global climatic changes associated with an asteroid impact as a result of living in environments that were always strongly seasonal. For example, life near the Poles has to adapt to living in darkness for half of the year and to an irregular food supply.

Professor Jane Francis from the British Antarctic Survey, a co-author of the study, said: "These Antarctic rocks contain a truly exceptional assemblage of fossils that have yielded new and surprising information about the evolution of life 66 million years ago. Even the animals that lived at the ends of the Earth close to the South Pole were not safe from the devastating effects of the mass extinction at the end of the Cretaceous Period."

While some previous studies have suggested that the demise of the dinosaurs and other groups was gradual, many scientists argue that the dinosaur fossil record in particular is patchy, and cannot compete with marine fossils in terms of quantity and biodiversity.

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Alternative odor receptors discovered in mice

This visual abstract depicts the discovery that chemosensory receptors in a subset of mammalian olfactory sensing neurons are structurally distinct from GPCRs, and multiple subtypes are expressed per neuron, implying an unexpected mechanism for olfactory detection and decoding.

Smell in mammals turns out to be more complex than we thought. Rather than one receptor family exclusively dedicated to detecting odors, a study in mice reports that a group of neurons surrounding the olfactory bulb use an alternative mechanism for catching scents. These "necklace" neurons, as they're called, use this newly discovered olfactory detection system to respond to odors that elicit instinctive responses, such as pheromones and the smell of seeds and nuts. Harvard researchers report the finding May 26 in Cell.

"Our work suggests that mammalian mechanisms for smell are not monolithic in terms of mechanism or logic, but rather can take many forms and can be mediated by multiple types of receptors," says senior author Sandeep Robert Datta, a neurobiologist at Harvard Medical School. "These findings revise our canonical view of how animals probe the chemical environment."

Nobel Prize-winning work back in 1991 showed that, in mammals, each sensory neuron in the main olfactory system expresses one type of G-protein coupled receptor (GPCR), which is specialized to detect a specific type of odor. The pattern of activity of all sensory neurons in the olfactory system allows us to distinguish between different odors present in the environment. This one-GPCR-per-neuron pattern also exists in the vomeronasal olfactory system, which is specialized for recognizing pheromones, suggesting a common and general logic for processing smell. Yet, a third olfactory system consisting of necklace neurons, so-called due to the unique circular pattern of their projections to the brain, also responds to diverse odors. It has not been clear which receptors are expressed by these neurons and what role they play in odor perception.

In the new study, Datta and his team discovered that necklace neurons in mice do not express GPCRs, unlike all other types of olfactory sensory neurons in mammals. Rather, these neurons express the MS4A class of proteins, which were previously not known to play a role in odor perception. Moreover, each necklace neuron expresses multiple types of MS4A receptors, in stark contrast to the one-receptor-per-neuron rule that organizes insect and other mammalian olfactory systems. These receptors respond to fatty acids that are specifically found in nuts and seeds, as well as a pheromone known to be aversive to mice.

"This discovery strongly suggests that the brain must be interpreting information from these receptors using a very different strategy from the one used by the brain to discriminate most odors," Datta says. "We speculate--but don't have the evidence to back this idea yet--that the MS4As are used as a kind of alert system for the brain, letting it know that something of real importance is out there in the world, but not telling the brain explicitly what that thing is."

By analyzing differences between Ms4a genes across mammalian species, the researchers found that the evolution of these genes preceded the advent of the mammalian receptors for taste and for pheromones. "The fact that the MS4As have been preserved for at least 400 million years suggests that these receptors play a crucial role in enabling animals to interact with the olfactory environment," Datta says.

In humans, MS4A receptors have previously been found in the intestines, lung cells, and even sperm cells. Based on the pattern of expression of MS4A receptors in different tissues, and the type of odors they detect, Datta suspects that MS4A molecules represent an ancient mechanism for sensing ethologically salient small molecules in the environment. "It is possible that this is the main function of the MS4As across species, and that the olfactory function of the MS4As is actually more recently evolved," Datta says.

For now, it is not clear whether MS4As in humans serve as odor receptors. In future studies, Datta and his team will examine whether MS4A proteins act as a primordial odor receptor across species. "This would be incredibly interesting, as it would suggest that many animals have a kind of hidden nose we were unaware of buried within their main olfactory system," Datta says.

Read more at Science Daily

Astronomers find giant planet around very young star

This false-color image from a sub-millimeter interferometric telescope shows the circumstellar disk of gas and dust that surrounds star CI Tau.

In contradiction to the long-standing idea that larger planets take longer to form, U.S. astronomers today announced the discovery of a giant planet in close orbit around a star so young that it still retains a disk of circumstellar gas and dust.

"For decades, conventional wisdom held that large Jupiter-mass planets take a minimum of 10 million years to form," said Christopher Johns-Krull, the lead author of a new study about the planet, CI Tau b, that will be published in the Astrophysical Journal. "That's been called into question over the past decade, and many new ideas have been offered, but the bottom line is that we need to identify a number of newly formed planets around young stars if we hope to fully understand planet formation."

CI Tau b is at least eight times larger than Jupiter and orbits a 2 million-year-old star about 450 light years from Earth in the constellation Taurus. Johns-Krull and a dozen co-authors from Rice, Lowell Observatory, the University of Texas at Austin, NASA and Northern Arizona University made the peer-reviewed study available online this week.

Earth and the sun are more than 4 billion years old, and while the 3,300-plus catalog of exoplanets includes some older and some younger than Earth, the obstacles to finding planets around newly formed stars are varied and daunting, Johns-Krull said. There are relatively few candidate stars that are young enough, bright enough to view in sufficient detail with existing telescopes and still retain circumstellar disks of gas and dust from which planets form. Stars so young also are often active, with visual outbursts and dimmings, strong magnetic fields and enormous starspots that can make it appear that planets exist where they do not.

CI Tau b orbits the star CI Tau once every nine days. The planet was found with the radial velocity method, a planet-hunting technique that relies upon slight variations in the velocity of a star to determine the gravitational pull exerted by nearby planets that are too faint to observe directly with a telescope. The discovery resulted from a survey begun in 2004 of 140 candidate stars in the star-forming region Taurus-Auriga.

"This result is unique because it demonstrates that a giant planet can form so rapidly that the remnant gas and dust from which the young star formed, surrounding the system in a Frisbee-like disk, is still present," said Lisa Prato of Lowell Observatory, co-leader of the young planet survey and a co-author on the paper. "Giant planet formation in the inner part of this disk, where CI Tau b is located, will have a profound impact on the region where smaller terrestrial planets are also potentially forming."

Additional team members were Patrick Hartigan, Naved Mahmud, Wei Chen, Wilson Cauley and Joshua Jones, all of Rice; Christopher Crockett and Brian Skiff of Lowell Observatory; Daniel Jaffe, Jacob McLane and Gregory Mace of the University of Texas at Austin; and Charles Beichman of NASA's Jet Propulsion Laboratory. Cauley is currently a postdoctoral researcher at Wesleyan University, and Crockett now writes for Science News.

The team observed CI Tau dozens of times from the University of Texas at Austin's McDonald Observatory near Fort Davis, Texas; the Lowell Observatory in Flagstaff, Ariz.; the NASA Infrared Telescope Facility and the Keck II telescopes on Mauna Kea, Hawaii; and the Kitt Peak National Observatory's 2.1- and 4-meter telescopes in southern Arizona.

Initial optical radial velocity data from McDonald Observatory confirmed that a planet might be present, and the team added photometry measurements from Lowell and five years of infrared observations from Hawaii, Kitt Peak and McDonald to rule out the possibility that the optical signal resulted from starspots or another masking phenomenon.

Johns-Krull said the team has examined about half of the young stars in the Taurus-Auriga survey sample, and the data from several of these suggest that more planets may be found.

Read more at Science Daily

Number of habitable planets could be limited by stifling atmospheres

Rendering of a possible alien Exo-planet. Elements of this image furnished by NASA.

New research has revealed that fewer than predicted planets may be capable of harboring life because their atmospheres keep them too hot.

When looking for planets that could harbor life, scientists look for planets in the 'habitable zones' around their stars - at the right distance from the stars to allow water to exist in liquid form. Traditionally, this search has focused on looking for planets orbiting stars like our Sun, in a similar way to Earth.

However, recent research has turned to small planets orbiting very close to stars called M dwarfs, or red dwarfs, which are much smaller and dimmer than the Sun. M dwarfs make up around 75 per cent of all the stars in our galaxy, and recent discoveries have suggested that many of them host planets, pushing the number of potentially habitable planets into the billions.

This month, both the TRAPPIST and Kepler planet-hunting telescopes have announced the discovery of multiple near-Earth-sized planets orbiting M dwarf stars, some within the habitable zones.

New research from Imperial College London and the Institute for Advanced Studies in Princeton, published in the Monthly Notices of the Royal Astronomical Society, has revealed that although they orbit smaller and dimmer stars, many of these planets might still be too hot to be habitable.

The scientists suggest that some of the planets might still be habitable, but only those with a smaller mass than Earth, comparable to Venus or Mars.

Dr James Owen, Hubble Fellow and lead author of the study from the Institute for Advanced Studies in Princeton, said: "It was previously assumed that planets with masses similar to Earth would be habitable simply because they were in the 'habitable zone'. However, when you consider how these planets evolve over billions of years this assumption turns out not to be true."

It was known previously that many of these planets are born with thick atmospheres of hydrogen and helium, making up roughly one percent of the total planetary mass. In comparison, the Earth's atmosphere makes up only a millionth of its mass. The greenhouse effect of such a thick atmosphere would make the surface far too hot for liquid water, rendering the planets initially uninhabitable.

However, it was thought that over time, the strong X-ray and ultraviolet radiation from the parent M dwarf star would evaporate away most of this atmosphere, eventually making the planets potentially habitable.

The new analysis reveals that this is not the case. Instead, detailed computer simulations show that these thick hydrogen and helium envelopes cannot escape the gravity of planets that are similar to or larger in mass than the Earth, meaning that many of them are likely to retain their stifling atmospheres.

However, all is not lost, according to the researchers. While most of the M dwarf planets that are Earth-mass or heavier would retain thick atmospheres, smaller planets, comparable to Venus or Mars, could still lose them to evaporation.

Read more at Science Daily

Close encounters of a tidal kind could lead to cracks on icy moons

A new model developed by University of Rochester researchers could offer a new explanation as to how cracks on icy moons, such as Pluto's Charon, formed.

Until now, it was thought that the cracks were the result of geodynamical processes, such as plate tectonics, but the models run by Alice Quillen and her collaborators suggest that a close encounter with another body might have been the cause.

Astronomers have long known that the craters visible on moons were caused by the impact of other bodies, billions of years ago. But for every crash and graze, there would have been many more close encounters. By devising and running a new computer model, Quillen, a professor of physics and astronomy at Rochester, has now shown that the tidal pull exerted by another, similar object could be strong enough to crack the surface of such icy moons. Quillen also thinks that "it might even offer a possible explanation for the crack on Mars, but that's much harder to model."

Icy moons exhibit what is know as brittle elastic behavior, which Quillen says most resembles "silly putty."

"If you take silly putty and throw it on the floor it bounces -- that's the elastic part," said Quillen. "But if you pull on it rapidly and hard enough, it breaks apart."

To simulate the behavior, Quillen modeled the icy moons as if their interior was made up of many bodies connected by springs (an N-body problem with springs). While N-body problems are often used to understand the effect of gravity on planets and stars, N-body problems had never been used to model the inside of an astronomical body, in this case the moons. Other models for icy moons used what are known as "rubble pile models."

"I was inspired by computer graphics code in how to model the icy moons," said Quillen. "The inside of the moons is similar to how blood splatter is modeled in games and the outer, icy crust is similar to modeling clothes and how they move. But I had to ensure the code matched the underlying physics!"

To ensure her model took into account the right properties for the materials that make up the moons, she worked with earth sciences Professor Cynthia Ebinger.

"I jumped at the opportunity to consider a novel alternative to plate tectonics, the governing theory to explain earthquakes, volcanoes and moving plates on Earth," said Ebinger. "My role was to provide some checks and balances to Alice's modeling and the choice of model parameters."

In the paper, to be published by the journal Icarus, Quillen states that "strong tidal encounters" may be responsible for the cracks on icy moons such as Charon, Saturn's Dione and Tethys, and Uranus' Ariel.

The key factor in determining if a crack is going to occur is the strain rate, the rate of pull from another body that would have caused the moons to deform at a rate that the top, icy layer could not sustain -- leading to cracks.

Read more at Science Daily

High altitude archaeology: Prehistoric paintings revealed

The paintings at the Abri Faravel. Two groups of roughly parallel lines, and two animals facing one another. (a) Normal light image; (b) Zoom of paintings -- colours enhanced with DStretch with the YBR matrix.

Archaeologists at the University of York have undertaken pioneering scans of the highest prehistoric paintings of animals in Europe.

Studying the rock paintings of Abri Faravel, a rock shelter in the Southern French Alps 2,133m above sea level, archaeologists used car batteries to power laser and white-light scanners in a logistically complex operation.

Producing virtual models of the archaeological landscape, researchers have now published the scans in Internet Archaeology -- an online, open-access journal.

Abri Faravel was discovered fortuitously in 2010. The rock shelter has seen phases of human activity from the Mesolithic to the medieval period, with its prehistoric rock paintings known to be the highest painted representations of animals (quadrupeds) in Europe.

The study of Abri Faravel and its paintings is part of a wider collaborative project between the University of York and the Centre Camille Jullian, Aix-en-Provence, France. Undertaking research in the Parc National des E?crins, the long-running study investigates the development of human activity over the last 8,000 years at high altitude in the Southern Alps.

Research conducted so far includes the excavation of a series of stone animal enclosures and human dwellings considered some of the most complex high altitude Bronze Age structures. Artefacts found in Abri Faravel also include Mesolithic and Neolithic flint tools, Iron Age hand-thrown pottery, a Roman fibula and some medieval metalwork.

However, the paintings are the most unique feature of the site, revealing a story of human occupation and activity in one of the world's most challenging environments from the Mesolithic to Post-Medieval period.

Dr Kevin Walsh, Senior Lecturer in York's Department of Archaeology and project lead, said: "After years of research in this valley, the day we discovered these paintings was undeniably the highlight of the research programme.

"Whilst we thought that we might discover engravings, such as in the Vallée des Merveilles to the south-east, we never expected to find prehistoric paintings in this exposed area that affords so few natural shelters.

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Supermassive black holes in 'red geyser' galaxies cause galactic warming

An international team of scientists, including the University of Kentucky's Renbin Yan, have uncovered a new class of galaxies, called "red geysers," with supermassive black hole winds so hot and energetic that stars can't form.

Over the last few billion years, a mysterious kind of "galactic warming" has caused many galaxies to change from a lively place where new stars formed every now and then to a quiet place devoid of fresh young stars. But the mechanism that produces this dramatic transformation and keeps galaxies quiet has been one of the biggest unsolved mysteries in galaxy evolution.

"These galaxies have the necessary ingredients for forming new stars but they are not doing it -- why?" said Yan, an assistant professor of physics and astronomy at UK.

Researchers compare it to having deserts in densely clouded regions; rain and vegetation would be expected, not a barren landscape. Yan and astronomers from the Sloan Digital Sky Survey (SDSS) are solving the mystery in a study published today in Nature, announcing the discovery of the red geysers.

Red geysers are old galaxies hosting low-energy supermassive black holes which drive intense interstellar winds. These winds suppress star formation by heating up the ambient gas found in galaxies and preventing it from cooling and condensing into stars.

Yan, also the survey scientist for the survey called Mapping Nearby Galaxies at Apache Point Observatory (MaNGA), was working with the international team, including lead author Edmond Cheung of the University of Tokyo, to study hundreds of galaxies when they caught a supermassive black hole blasting away at the cold gas in its host galaxy.

"With MaNGA's technological upgrade to the Sloan Foundation Telescope, we can make detailed maps of galaxies ten to a hundred times faster than we could just ten years ago," Yan said.

Yan and his team at MaNGA are mapping the details of 10,000 nearby galaxies -- the largest survey yet of its kind -- with the goal to understand the galaxies' life cycles. Unlike previous SDSS surveys, they are not only mapping the centers of galaxies where supermassive black holes live, but the outer edges of the galaxies as well, which allowed them to discover the red geyser galaxy.

The winds powered by these supermassive black holes could come and go quickly. It is difficult to catch the moment they show up. "Since MaNGA studies so many galaxies, our snapshots can reveal even the quickest changes to galaxies," Yan said. "And that's how we found Akira."

"Akira," an example of a red geyser galaxy nicknamed by Cheung, has a companion galaxy that called "Tetsuo." Akira is pulling gas away from Tetsuo, which fuels Akira's supermassive black hole. The winds driven by the black hole are the reason that Akira is currently a red geyser galaxy.

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Some Sharks Worry While Others Take Risks

Yes, sharks got personality too.

Striking personality differences have just been observed in Port Jackson sharks, which are relatively common sharks in the waters off of southern Australia, including near Port Jackson.

The study, published in the Journal of Fish Biology, adds to the growing body of evidence that shark individuals of many, if not all, species are distinct, unique beings just as no two humans are exactly the same.

"Over the past few decades, personality research has shown that nearly 200 species of animals demonstrate individual personality," lead author Evan Byrnes of Macquarie University said in a press release. "Personality is no longer considered a strictly human characteristic, rather it is a characteristic deeply ingrained in our evolutionary past."

Personality in humans helps to define who we are and how likely we are to respond to certain situations. Some people tend to be bold risk takers, for example, while others are often more wary and careful. Prior research suggests that such inclinations are due to a combination of genetic and environmental factors.

Many aspects of behavior are relatively stable and predictable over time, and it is these general consistencies that define someone's personality.

The researchers designed trials to test the sharks' boldness, which is a measure of the propensity to take risks, but it also influences individual health through its correlation with stress hormones and more. Seventeen juvenile male and female Port Jackson sharks were caught at different locations within their habitat for the study.

 At first the sharks were introduced to a tank where they were provided with shelter, and timed to see how long it took for each shark to emerge from their refuge box into a new environment.

For the second test, the researchers held each shark with two hands from underneath for just a minute before release. Byrnes and co-author Culum Brown then noted how quickly the sharks recovered from this bit of stress.

Read more at Discovery News

Mars to Make Closest Approach in 11 Years

This Monday evening (May 30) at 5:35 p.m. EDT, Mars will be the closest it has been to Earth since Oct. 5, 2005.

Last Sunday morning (May 22), Mars reached opposition with the sun, meaning the Red Planet, Earth and the sun were all arrayed in a straight line. But the moment did not mark Mars' closest approach to Earth.

This Monday evening (May 30) at 5:35 p.m. EDT (2135 GMT), Mars will be the closest it has been to Earth since Oct. 5, 2005: 0.50321377 astronomical units (AU), or 46,762,695 miles (75,279,709 kilometers). (One AU is the average distance from Earth to the sun — about 93 million miles, or 150 million km.)

Opposition and closest Earth approach occur on different days because the orbit of Mars is elliptical. When opposition occurred May 22, Mars was still approaching Earth on its orbital track, and will not reach minimum distance to Earth until May 30. After 5:35 p.m. EDT on that date, Mars will begin to recede from Earth.




The graphic shows how Mars would appear viewed with a superb telescope at the exact instant of closest approach. The landing site of NASA's Opportunity rover is just rotating out of sight on the Red Planet's eastern limb, and the solar system's highest volcano, Olympus Mons, is just coming into view on the western limb. Mars' Valles Marineris, far larger and deeper than Earth's Grand Canyon, is close to the center of the disk, and the dusky Acidalia Planitia is high to the north, close to the small north polar cap.

What can you see with an ordinary amateur telescope? Very little, I'm afraid. You might see a hint of the polar cap, and a few dusky shadings. Astronomers studying Mars from Earth use a slightly different terminology. Acidalia Planitia is known as the Mare Acidalium, the dark area to the southeast of the Valles Marineris as the Mare Erythraeum, and the dark area just south of Marineris is called Solis Lacus. These older names are, like the "seas" and "lakes" on the moon, imaginary bodies of water on a dry world.

When lighting conditions are exactly right, Olympus Mons can be spotted by keen-eyed observers on Earth, but the mighty Valles Marineris has never been seen from here (although the huge canyon complex has been mapped in detail by satellites in orbit around Mars).

 Regular observers of Mars soon become familiar with the normal patterns of light and dark on its surface, known as "albedo markings." If you observe Mars over a few hours, you will see these markings appear to move slowly across the disk, as Mars rotates just slightly more slowly than Earth, a full rotation taking 24 hours, 37 minutes and 23 seconds. Because of Mars' slightly longer day, if you observe Mars at the same time on successive nights, the markings will seem to move.

Sometimes the albedo markings seem to change shape. Usually this is caused by gigantic dust storms sweeping across the face of Mars. Recently, British amateur astronomer Damian Peach reprocessed a number of old images made of Mars in the 1930s, 1940s and 1950s, using modern image-processing techniques. Peach's work revealed amazing detail not visible in the original images, and some of this detail has shown clear changes from back then to modern times. It is thought that these changes result from the shifting sands of Mars over the decades.


Read more at Discovery News