Paul Harris

Se espera que un satélite americano grande del espía caiga para conectar a tierra una cierta hora en el mes próximo, funcionarios dichos ayer.

Es confuso donde la ruina del espacio pudo venir abajo, pero podría golpear la tierra en último febrero o marcha. También no se sabe si el satélite podría contener los materiales potencialmente peligrosos, tales como un reactor de propulsión nuclear.

Los funcionarios dijeron que habían perdido control sobre el satélite y que habían informado a países alrededor del mundo sobre el problema potencial. Las agencias de estatal apropiadas del `están supervisando la amenaza… que estamos mirando opciones potenciales para atenuar cualquier daño este satélite puede causar,' portavoz Gordon del consejo de la seguridad nacional Johndroe dijo la agencia de noticias del AP.

Johndroe declinó a la opinión si tales medidas podrían incluir tirar abajo del satélite con un misil.

China condujo recientemente tal operación por el destruir de sus propios satélites de la tierra a la prueba un sistema del misil del espacio. Sin embargo, ese movimiento creó una nube de fragmentos y otros satélites tuvieron que ser maniobrados en nuevas órbitas para evitar de ser golpeada por la ruina.

Otros satélites han caído a la tierra inofensivo antes. En 2002 porciones de ciencia un satélite llovió abajo sobre el golfo persa. El reingreso más grande ocurrió cuando Skylab, un laboratorio abandonado 78 toneladas del espacio que pertenecía a la NASA, cayó de órbita en 1979. Vino abajo en una masa ardiente de la ruina que cayó principalmente en el Océano Índico y sobre Australia.

Nadie fue dañada en cuál era una sensación de los medios. Un periódico de San Francisco ofreció una recompensa por cualquier persona que trajo un pedazo de Skylab a su redacción. El premio $10.000 fue recogido por un hombre australiano occidental joven que encontró un pedazo de él en su azotea en la ciudad pequeña de Esperance y viajado a América con él.

En la NASA los ingenieros 2000 trajeron abajo un satélite mucho más pequeño en una parte distante del Océano Pacífico. Eso es probable no ser posible en este caso pues el objeto ha perdido toda la energía y propulsión. This makes it impossible to dictate where or when the satellite will come down - or if it will just burn up in the atmosphere.

One of the most disturbing examples of space pollution occurred in a type of Soviet satellite launched from 1967 to 1988. The Rorsat-class reconnaissance satellites contained a nuclear reactor as a power source. It was later shown that 16 of 31 Rorsats had been leaking potentially radioactive coolant into space, creating a trail of droplets in orbit.

Life on Mars? Amazing photos from Nasa probe reveal image of mystery figure on Red Planet

The Daily Mail 

Does this photograph really prove that we are not alone in the universe?

Images beamed back from Mars would suggest so - although to sceptics, it could just be a strange rock formation.

Nasa’s Mars Explorer Spirit sent back images from the surface of the Red Planet four years ago, and there was initial disappointment among scientists that they lacked any signs of life.

The ‘alien’ appears to be walking downhill

But space and science fiction enthusiasts are convinced there is more than meets the eye, and after years of studying the images, have found what appears to be an alien figure walking downhill.

The discovery of the life-like figure ambling across the surface of the planet is likely to further boost intrigue in our nearest neighbouring planet.

An earlier rock formation, dubbed “the face of Mars” showed what appeared to be a human head staring into the night sky.

The pictures, found on a Chinese website, are now creating a stir of excitement on the internet.

Alien life: What seems to be a human-like Martian is pictured on Mars

One keen stargazer said: “These pictures are amazing. I couldn’t believe my eyes when I looked and saw what appears to be a naked alien running around on Mars.”

Nasa’s Mars Explorer Spirit is now starting its fourth year of exploration.

Painstaking: Space enthusiasts spent four years analysing this image, which on much closer inspection shows the ‘alien’

Rovers are deployed because it has so far been too costly and difficult to achieve a manned mission to Mars, and because probes and satellites are too limited to explore the Martian surface.

The Spirit rover was launched on June 10, 2003.

Planet X Nibiru Spotted

Planet X Nibiru Spotted - The funniest bloopers are right here

Anne Minard in San Francisco, California

NASA spacecraft have revealed new insights into the forces that cause the northern lights, including giant magnetic “ropes” between Earth and the sun.

Until now, scientists haven’t had adequate tools to study how energy from the sun is captured by Earth’s magnetic field to trigger the awe-inspiring phenomenon.

“What it shows is promise,” said Vassilis Angelopoulos, researcher at the University of California at Los Angeles and principal investigator for a new NASA mission to study auroras.

“We’re coming up on a new era in space physics.”

The findings were presented at a teleconference today at the fall meeting of the American Geophysical Union in San Francisco.

Perfect Storm

The latest discoveries began on March 23, when a “substorm” erupted over Alaska and Canada, producing vivid auroras for more than two hours. During such an event, the northern lights’ green and white streaks periodically build in intensity until they blast apart into multicolored, fragmented lights.

(Download a desktop photo of the northern lights.)

A network of ground cameras photographed the display from below while a series of five satellites, collectively called THEMIS, looked on from above.

(Read about the THEMIS mission and the probes’ launch earlier this year.)

“The auroras surged westward twice as fast as anyone thought possible, crossing 15 degrees of longitude in less than one minute,” Angelopoulos said.

“The storm traversed an entire polar time zone, or 400 miles [640 kilometers], in 60 seconds flat.”

The images revealed a series of staccato outbursts each lasting about ten minutes. Some of the bursts died out, while others reinforced each other.

The researchers likened the substorm’s power to a magnitude 5.5 earthquake.

Magnetic “Ropes”

NASA’s THEMIS probes are designed to unravel the mysterious dynamics that create such colorful displays.

Angelopoulos said the prime observation season for the northern lights hasn’t begun yet, but already the results are exciting.

“The satellites have found evidence of magnetic ‘ropes’ connecting Earth’s upper atmosphere directly to the sun,” said David Sibeck, project scientist for the mission at NASA’s Goddard Space Flight Center in Greenbelt, Maryland.

These ropes could serve as conduits for waves of charged particles from the sun called solar wind.

“We believe that solar wind particles flow in along these ropes, providing energy for geomagnetic storms and auroras.”

Spacecraft have detected hints of these ropes before, but a single spacecraft was insufficient to map their 3-D structure.

THEMIS’ identical micro-satellites were able to perform the feat.

The satellites have also glimpsed the evolution of heat waves and pressure blasts emitted from the northern lights’ substorm.

Angelopoulos likened THEMIS’ role to that of weather stations in our ability to predict atmospheric weather a century ago.

“These substorm processes are really helping us to understand and predict space weather,” Angelopoulos said.

 Astronomers Select Top Ten Most Amazing Pictures Taken by Hubble Space Telescope in Last 16 Years

http://cph-theory.persiangig.com/2031-ehubblepics.htm

By Seth Borenstein

There is no evidence astronauts were drunk or had been drinking heavily before launching into space, an internal NASA investigation found Wednesday.

An independent astronaut health panel’s report of two unsubstantiated instances of heavy alcohol use before flights grabbed headlines in July. But when NASA’s safety chief tried to confirm the allegations, he came up empty.

“I was unable to verify any case in which an astronaut spaceflight crewmember was impaired on launch day,” or any case where a manager disregarded a recommendation that an astronaut not fly, said a 45-page report prepared by NASA safety chief Bryan O’Connor. He is a former astronaut and shuttle accident investigator.

O’Connor’s review went back 20 years and involved interviews with 90 astronauts, flight surgeons and other NASA officials.

However, O’Connor said flight surgeons should play a stronger “oversight” role in launch day activities.

Twenty flight surgeons signed an e-mail to O’Connor saying they have never seen any drunken astronauts before a launch or training jet flight.

O’Connor looked through 40,134 government and contractor reports of mishaps and problems dating back through 1984 – many of them anonymous – and none of them involved alcohol or drug abuse by astronauts.

Wednesday’s report confirms what top NASA officials had been saying in the last few weeks: There was no proof of drunken astronauts before launch.

In July, an independent panel said there were at least two unverified and unidentified instances of astronauts drinking heavily before a flight. The panel was formed to look at astronaut health issues because of the bizarre case of astronaut Lisa Nowak, who was arrested and charged with attempted kidnapping of a romantic rival.

The panel’s 12-page report last month said: “Interviews with both flight surgeons and astronauts identified some episodes of heavy use of alcohol by astronauts in the immediate preflight period, which has led to safety concerns.”

One instance involved a shuttle astronaut that a colleague claimed had had to much too drink; the colleague alerted others only after the launch was delayed because of mechanical instances.

O’Connor, using the clues in the July report, figured that that claim was probably one of three missions between 1990 and 1995. So he talked to at least two astronauts on each of those missions and the astronaut chiefs at the time and no one verified the claims.

The other involved an astronaut drinking alcohol before flying on a Russian Soyuz capsule to the international space station. Drinking, especially toasts, are common in the Russian space program.

O’Connor’s report said the claim was that a flight surgeon was worried the night before launch that the astronaut was so drunk that “he might suffer an airway obstruction.” O’Connor said he was limited by privacy issues, but he couldn’t confirm this either.

In both cases – in which no names were given – the report said that flight surgeons and/or fellow astronauts raised safety worries with nearby officials in charge, yet “the individuals were still permitted to fly.”

NASA administrator Michael Griffin this month pronounced pre-launch preparations for astronauts to be so visible that it is nearly impossible to sneak a drink.

“They would have to really want to drink and hide it really well,” Griffin said before the launch of the shuttle Endeavour. He called the charges “uncredible.”

By Virginie Montet  THE US space agency faced a full-blown crisis today as US politicians promised to probe how NASA allowed astronauts to fly missions while drunk as well as the sabotage of in-flight computers.

The US House of Representatives Science and Technology committee called an oversight hearing for September, after a NASA report found astronauts had shown up to work drunk.

House Space and Aeronautics subcommittee chairman Mark Udall warned that the report was a “wake-up” call.

“We need to understand what happened and why, whether anyone is going to be held accountable, and what the agency is going to do to fix these apparently deep-seated problems,” he said.

The report released by NASA found “heavy use of alcohol” inside the standard 12-hour “bottle to throttle” abstinence period for flight crew.

NASA has recently regained its confidence after the 2003 breakup of Columbia with seven aboard, and years of testing to prove the reliability of its shuttle program, as well as its management procedures.

However, in February, NASA’s reputation was sullied again when astronaut Lisa Nowak allegedly tried to kidnap a woman dating another astronaut.

In the wake of Nowak’s arrest, NASA set up an internal panel to review astronaut health, and was handed reports of astronaut drinking.

Air Force physician Richard Bachmann, who authored the report, said one drinking incident came ahead of a shuttle mission that was eventually delayed.

The astronauts then wanted to fly on a T-38 supersonic jet used by NASA.

The second case involved a Russian Soyuz mission bound for the International Space Station (ISS), Colonel Bachmann said.

There was “no way to know if they were isolated incidents or the top of large iceberg”, he said.

NASA said: “Both flight surgeons and astronauts identified some episodes of heavy use of alcohol by astronauts in the immediate preflight period which has led to flight safety concerns.”

“However, the individuals were still permitted to fly,” it said.

The panel interviewed 14 astronauts, eight flight surgeons, five family members and other staff for the 12-page report, which noted that astronauts lacked regular mental-health assessments and felt pressure to hide their problems.

There was more bad news for the space agency this week when NASA officials said workers found a computer due to be transported by shuttle Endeavour in an August mission to the ISS had been apparently sabotaged, its wires cut.

By Jean-Louis Santini

The hunt for evidence of life on Mars will go underground next year when a NASA probe digs beneath the surface of the red planet’s arctic northern plains, US scientists revealed Monday. In a departure from previous missions — which have seen robotic vehicles explore the planet’s hills and craters — NASA’s Phoenix Mars Lander will instead dig into Martian soil for conditions favorable to past or present life. US scientists want Phoenix to try and determine whether frozen water near the planet’s surface might periodically melt enough to sustain a viable environment for microbes.

“Phoenix will complement our strategic exploration of Mars by being our first attempt to actually touch and analyze Martian water — water in the form of buried ice,” said Doug McCuistion, director of the Mars Exploration Program.

Phoenix will blast off from Florida sometime in August, beginning a journey that will end several million miles and around nine months later with a risky descent and landing.

Once safely in position on the Martian surface, Phoenix will deploy a set of advanced research tools never before used on the planet.

The solar-powered craft is equipped with a 2.3 meter (7.5 foot) robotic arm that will go vertically into the soil, aiming to strike the icy crust that is believed to lie within a few inches of the surface.

Peter Smith, Phoenix’s principal investigator at the University of Arizona, Tucson, said the craft would be able to study the history of the ice and analyze how liquid water has modified the chemistry of the soil.

“In addition, our instruments can assess whether this polar environment is a habitable zone for primitive microbes,” Smith said.

The Phoenix’s robotic arm is capable of lifting samples to two instruments on its deck. One instrument will use a heater to check for water and carbon-based chemicals considered essential building blocks for life, while the other will analyze the soil chemistry.

The lander also boasts an onboard meteorology station which will assess water and dust levels in the atmosphere as well as monitor weather throughout the three-month-long mission.

First, however, Phoenix must touch down in one piece.

“Landing safely on Mars is difficult no matter what method you use,” said Barry Goldstein, the project manager for Phoenix at NASA’s Jet Propulsion Laboratory in Pasadena, California.

“Our team has been testing the system relentlessly since 2003 to identify and address whatever vulnerabilities may exist.”

As with previous Mars missions, the Phoenix will deploy a heat shield to slow its high-speed entry, before opening a supersonic parachute that will slash its speed to about 217 kilometers (135 miles) per hour.

The lander then separates from the parachute and fires pulsed descent rocket engines to slow to about 9 kilometers per hour (5.5 miles per hour) before landing on its three legs.

Source: Agence France-Presse

Spacewar

Satellite tracking software freely available on the Internet and some textbook physics could be used by any organization that can get hold of an intermediate range rocket to mount an unsophisticated attack on military or civilian satellites. Such an attack would require modest engineering capability and only a limited budget. That is according to researchers writing in Inderscience Publishers’ International Journal of Critical Infrastructures.

A terrorist organization or rogue state could threaten essential satellite systems, according to Adrian Gheorghe of Old Dominion University Norfolk, in Virginia, USA and Dan Vamanu of “Horia Hulubei” National Institute of Physics and Nuclear Engineering, in Bucharest, Romania. Military satellites, global positioning systems, weather satellites and even satellite TV systems could all become victims of such an attack. Gheorghe and Vamanu have carried out an analysis of just how easy it could be to knock out strategic satellites, their findings suggest that dozens of systems on which military and civilian activities depend make near-space a vulnerable environment. The team used a so-called “mathematical game” and textbook physics equations for ballistics to help them build a computer model to demonstrate that anti-satellite weaponry is a real possibility.

Accuracy and elegance are not issues in carrying out a satellite attack, the researchers say, as long as the projectile hits the satellite. In fact, all it would take to succeed with an amateurish, yet effective anti-satellite attack would be the control of an intermediate range missile, which is well within the reach of many nations and organizations with sufficient funds, and a college-level team dedicated to the cause. “Any country in possession of intermediate range rockets may mount a grotesquely unsophisticated attack on another’s satellites given the political short-sightedness that would be blind to a potentially devastating retaliation,” the researchers say.

On January 11, 2007, China deliberately destroyed one of its own weather satellites in a test, which some analysts suggested as having the potential to revive a techno-political race believed to be defunct since the 1980s. According to Gheorghe and Vamanu that was the cool analytical view, but some hot diplomats are quoted as saying this demonstration is “inconsistent with international efforts to avert an arms race in outer space and undermining the security in outer space”.

“While it may be true that, when it comes to nuts and bolts, things may not be quite as simple as they sound here, the bare fact remains - it can be done.” Their conclusions suggest that the risk of deliberate satellite sabotage should be placed higher on the security agenda.

Scientists now say that an ocean several miles deep once covered a third of the surface of the planet, enough water to support the origin and evolution of life. The red planet, they said, had once been a deep blue, just like Earth.

By Steve Connor

For generations, people have been fascinated by the idea of life on Mars. It began in earnest in the late 19th century when an Italian astronomer called Giovanni Schiaparelli peered through his telescope and saw long, straight lines etched on to the surface of the red planet. He called them “canali” and others quickly became convinced that an alien civilisation had built a sophisticated network of canals, perhaps to move water from one region of Mars to another.

In 1897, H G Wells published The War of the Worlds, which describes an invasion of Martians covetous of Earth’s rich natural resources. When Orson Welles broadcast his famous radio adaptation of the book in 1938, mass panic ensued when thousands of Americans truly believed that the Earth was under attack by Martians.

The true nature of Mars, however, emerged in the late 1960s when the Mariner space missions paid the first visits to Earth’s smaller neighbour. Mars turned out to be heavily cratered, dotted with extinct volcanoes, colder than Antarctica and, crucially, drier than the Atacama desert - the driest place on Earth.

Mars was a dead place, a desiccated wasteland sterilised by harsh solar radiation. Anything approximating to a biological molecule on the Martian surface would be instantly irradiated. There were certainly no canals, no water and quite evidently no life - or, at least, not life as we know it.

When the Viking spacecraft visited Mars in the 1970s they confirmed this view of a lifeless planet. Viking images depicted a bitterly cold, dry landscape of rock and dust, but they also showed another feature that began a fresh debate over whether Mars was always such a dead planet. They detected what seemed to be the shorelines of ancient oceans - and where there was liquid water, there was a strong possibility of life.

Yesterday, American and Canadian scientists reignited the debate over whether there was ever a giant ocean of liquid water on Mars. According to a study published in the journal Nature, an ocean several miles deep once covered a third of the surface of Mars - easily enough water to support the origin and evolution of life. The red planet, they said, had once been a deep blue, just like Earth.

The Viking probes of 25 years ago detected two possible ancient shorelines near the poles of the planet. The shorelines stretched for thousands of kilometres around what looked like dried-up ocean basins. Each shoreline had the distinctive “edges” separating the rugged, weathered landscape of dry land from the smoother, sediment-filled seabed.

The similarity to features seen on Earth were obvious for all to see. The Viking probes had mapped two Martian shorelines - one called Arabia and the other named Deuteronilus - and scientists dated them to be between two and four billion years old.

However, a major problem soon emerged. In the 1990s, Nasa’s Mars Global Surveyor mapped the topography of Mars to a resolution of 300 metres and it quickly became apparent that the two “shorelines” varied in elevation by almost two miles. Differences in height between shorelines on Earth were well known - caused by variations in global sea levels - but the dramatic difference on Mars made it highly unlikely that these “shorelines” were created by an ancient ocean.

The topographic reality revealed by the Mars Global Surveyor became the biggest stumbling block to the notion that Mars was once smothered in water. It was also a blow to the idea of Martian life, because without water in liquid form it was difficult to see how life could ever get going in the first place, never mind evolving into even the most simple of microbial lifeforms.

The latest study seems to have lifted this barrier to the idea of an ocean on Mars. Scientists at the University of California, Berkeley, the University of Toronto and the Carnegie Institution in Washington have offered a powerful explanation for why the two ancient shorelines of Mars are separated by such dramatically different elevations.

They have shown that the axis of spin of Mars, which determines the position of the true poles rather than the magnetic poles, has varied by as much as 50 degrees during the long geological history of the planet. In other words the shorelines have moved around because the planet itself has in the past shifted significantly on its axis - resulting in huge changes to the shape of the Martian landscape and its shorelines.

“When the spin axis moves relative to the surface, the surface deforms, and this is recorded in the shoreline,” explained Professor Michael Manga, of the University of California, Berkeley.

Planets such as Earth and Mars have an outer shell, or lithosphere, and a change in the spin axis can cause the solid surface to deform differently than the liquid ocean and this explains the warped shorelines, according to Taylor Perron, the lead author of the study, who is now at Harvard University.

“On planets like Mars and Earth with an outer shell, or lithosphere, that behaves elastically, the solid surface will deform differently than the sea surface, creating a non-uniform change in the topography,” Dr Perron said.

Jerry Mitrovica of Toronto University said that the evidence is now so overwhelming that this can explain why the shorelines of Mars formed at such dramatically different heights - more than a mile difference in elevation.

“At some point in the planet’s history, a major shift of mass caused the pole to wander about 50 degrees towards its current location and the resulting change in orientation dramatically warped the topography and the ancient shorelines,” Professor Mitrovica said.

One critical piece of evidence in support of this hypothesis is the position of the immense Tharsis volcano on Mars - the biggest in the Solar System and some 10,000 times bigger than Mauna Loa, the biggest volcano on Earth. Tharsis is so massive that it will always reorient itself to sit on the planet’s equator - it will be spun out to the widest point on the axis of spin, just like a centrifuge. The scientists found that their assessment of how the position of the Martian poles has moved matches precisely the movements of Tharsis as it keeps shifting to maintain its place on the changing position of the equator.

“The chances of this happening randomly are less than 1 in 10,000,” Professor Mitrovica said.

As yet the scientists do not understand why the spin axis of Mars moved so much. It may have resulted from a massive deluge of water on the Martian surface resulting in the first Arabia shoreline. The shift in weight caused the planet to tilt on its axis. Once the water disappeared, the pole could have shifted back, then shifted again as a second deluge created the Deuteronilus shoreline. “What we don’t know is what caused the poles to shift on Mars and what happened to the water. The ocean may have been gradually converted into water vapour, moved to higher elevations, and flowed beneath the surface. There could be a large mass of water deep within Mars,” Dr Perron said.

But what happened to the water on Mars is critical in the assessment of whether there is still life on the planet. Many scientists believe there is a strong chance that if liquid water exists deep under the surface of Mars, there is a good chance that simple lifeforms may still be living underground.

At the end of last year, Nasa scientists analysed successive satellite images of craters on Mars that appeared to show erosion marks caused by streams of liquid water bubbling up from under the surface of Mars and flowing down the sides of the crater. The scientists were convinced that these marks were not simply created by the movement of dry dust.

This finding came on top of a succession of studies pointing to the possibility that water must have flowed on the surface of Mars. And now the major obstacle to the idea of a massive ocean on Mars has been removed. It really does seem that the red planet was once a water-rich world, and that some of this water may still be present in underground deposits.

But what does this mean for life? The point is that without water in its liquid form it is difficult to imagine that life could exist. Water does not make life obligatory, but it does make it far more likely. As yet the only direct evidence for life on Mars has been highly controversial. Ten years ago, Nasa scientists announced that they had found possible signs of life on a Martian meteorite called ALH84001. The potato-sized lump of rock fell to Earth 13,000 years ago and a detailed analysis threw up chemical signatures of life, as well as rod-shaped structures that looked like terrestrial bacteria, but smaller.

Other scientists have been bitterly critical of this analysis, which has gone through a series of claims and counterclaims concerning its authenticity. The only way of truly solving this problem is to look for a similar piece of rock on Mars and bring it back to Earth for analysis. And the best place to find Martian fossils is in sedimentary rock formed by an ocean. At least scientists looking for life on Mars now have a better idea where to find it.

Ring of gravity in outer space lets scientists ‘see’ exotic material

Mark Henderson

A rippling halo of dark matter, the mysterious substance thought to account for much of the mass of the Universe, has been discovered around a distant cluster of galaxies.

The ring, which is 2.6 million light years across, has been detected by astronomers using the Hubble Space Telescope, providing some of the strongest evidence yet for the existence of the enigmatic material.

Dark matter does not shine like stars, or reflect visible light like planets, so it cannot be directly seen. Nevertheless, scientists have calculated that it makes up almost a quarter of the mass of the Universe.

The ordinary matter that can be seen through telescopes – stars, galaxies and dust – can account for no more than 4 per cent of the Universe as a whole, as it does not generate sufficient gravity for the cosmos to be stable.

Models suggest that about 23 per cent of the total mass is made up of dark matter, while the remaining 73 per cent is something even odder: a dark energy that drives the Universe’s expansion.

The nature of both dark matter and dark energy remains elusive, though scientists suspect the former is made up of as yet unknown particles that pervade the entire Universe, but which have little effect on the ordinary particles we can see. These are sometimes known as weakly interacting massive particles, or “wimps”.

The new observations of the galaxy cluster ZwCI0023+24, which lies five billion light years away from Earth, promise to offer fresh clues to the nature of the substance.

Though the ring cannot be seen physically, its presence has been confirmed by observing how its gravity bends the light of more distant galaxies that lie behind it, as seen from Earth.

James Jee, of Johns Hopkins University in Baltimore, Maryland, who led the discovery team, said: “This is the first time we have detected dark matter as having a unique structure that is different from the gas and galaxies in the cluster.

“Although the invisible matter has been found before in other galaxy clusters, it has never been detected to be so largely separated from the hot gas and the galaxies that make up galaxy clusters.

“By seeing a dark matter structure that is not traced by galaxies and hot gas, we can study how it behaves differently from normal matter.”

The discovery, which is published in the Astrophysical Journal, was made unexpectedly when Dr Jee’s team was attempting to map the distribution of dark matter within the galaxy cluster.

At first, the astronomers were convinced that they had made a mistake when a set of concentric rings, like ripples in a pond, appeared from their data.

“I was annoyed when I saw the ring because I thought it was an artefact, which would have implied a flaw in our data reduction,” Dr Jee said. “But the more I tried to remove the ring, the more it showed up. It took more than a year to convince myself that the ring was real. I’ve looked at a number of clusters and I haven’t seen anything like this.” The likely explanation for the ring comes from previous research into the same cluster, published in 2002 by Oliver Czoske, of Bonn University in Germany, which indicated that it had collided with another galaxy cluster between one billion and two billion years ago.

Computer simulations of this cosmic collision suggest that the dark matter fell towards the centre of the cluster and then rippled back out, creating the characteristic pattern.

Holland Ford, also of Johns Hopkins University, said: “By studying this collision, we are seeing how dark matter responds to gravity. Nature is doing an experiment for us that we can’t do in a lab, and it agrees with our theoretical models.”

Dr Jee said: “The collision between the two galaxy clusters created a ripple of dark matter which left distinct footprints in the shapes of the background galaxies. It’s like looking at the pebbles on the bottom of a pond with ripples on the surface.

“The pebbles’ shapes appear to change as the ripples pass over them. So, too, the background galaxies behind the ring show coherent changes in their shapes due to the presence of the dense ring.”

Points of light

— The points of light in the background of the image above are galaxies observed in visible light with the Hubble Space Telescope, in the galaxy cluster ZwCl0024+1652

— The concentric blue dusty rings show the distribution of dark matter in the galaxy cluster. Though the dark matter itself is invisible, its position has been calculated from its gravitational effect on light reaching Earth from the background galaxies

— The existence of dark matter was proposed in 1933 by the astrophysicist Fritz Zwicky, whose studies of galaxy clusters found they had far more mass than could be predicted from visible light alone

— One theory about dark matter is that it is made of weakly-interacting massive particles or “Wimps”

— Billions of Wimps are thought to be passing through the body every instant, but they are almost impossible to detect

— An Anglo-American team is currently engaged in a search for Wimps in a disused salt mine 3,500ft under the cliffs of the North Yorkshire coastline

Source: Johns Hopkins University, Times database