Saturday, December 31, 2011

A Dying Star: The Dumbbell Nebula

The outer layers of a dying star form a huge cloud of gas, lit up by the core.

In an estimated 5billion years time, our own sun will turn into a nebula like this one.

The photograph, taken by Bill Snyder and featured on Nasa’s Astronomy Picture of the Day website, shows the Dumbbell Nebula, or M27.

It is about 1,360 light years from earth and can be seen by stargazers with amateur telescopes and even binoculars.

The nebula was spotted by accident in the 18th century but experts still do not know the exact way in which dying stars expel gases.

NASA said: “M27 is one of the brightest planetary nebulae on the sky, and can be seen toward the constellation of the Fox (Vulpecula) with binoculars.

“It takes light about 1000 years to reach us from M27, shown in colours emitted by hydrogen and oxygen."

Self-Balancing Electric Unicycle - YouTube

Stephan Boyer, a student at the Massachusetts Institute of Technology (MIT) has created the world's first self-balancing electric unicycle. Designed like a mini Segway, it is fondly named "Bullet" by its inventor.

The cyclist has to adjust his position to avoid falling; needing to lean forward to accelerate and backward to slow down. However, Boyer has admitted it isn't quite so easy to ride the cycle, adding that even his unicycling friends struggled to come to grips with it. The principal problem seems to be that the unicycle veers to the right, at the slightest inclination.

Boyer stated, on his blog, it took him several hours to learn to ride in a straight line and several more to control his turns. Although the bike takes some getting used to, it does offer a top speed of 15 mph and can travel up to five miles on a single charge.

The unicycle also includes a panic button, designed to turn off the electric motor in case of an emergency.

Friday, December 30, 2011

Europe Acts to Save Sharks from Finning and Fishing Nets

Europe acts to protect sharks (long version)
This video graphically illustrates the beauty of sharks and the danger which threaten their survival. The images are only copyright free for a duration of 5 years as from january 2009 until january 2014.

These images can only be used in context of this video news release. The images have been provided by Greenpeace and OceanFootage.

To read more about EUROPEAN Commission Protection measures click here

Rusia's Orbital Tec h: Commercial Space Station (CSS)

A Russian company announced plans for the world's first hotel in space.

Orbital Technologies aim to have their Commercial Space Station (CSS) open in 2016.

According to plans unveiled in Moscow, the hotel would orbit 217 miles above ground and have room for seven guests in four cabins - each with views of the Earth. Guests can expect to pay £100,000 for five days on board, as well as £500,000 for the journey, which would see them spend two days travelling on a Soyuz rocket.

Successful Russian Soyuz Launch: Six Communication Satellites in Payload

After suffering a setback when a rocket crashed early last week, Russia recovered with the successful launching of a Soyuz rocket with six communications satellites into orbit on Wednesday.

The Soyuz 2 rocket launched six satellites for Louisiana-based communications provider Globalstar at 12:09 p.m. EST (1709 GMT) from the snow-covered central Asian spaceport of Baikonur Cosmodrome in Kazakhstan, the same site used by another Soyuz 2 booster that earlier met with disaster when it crashed in Siberia, destroying a Russian military communications satellite.

Wednesday's launch used a Soyuz 2-1a version of Russia's usually dependable Soyuz workhorse rocket. The booster design uses an older third stage rocket engine than the one used in the Soyuz 2-1b booster that crashed on Dec. 23.

ussia's ITAR-Tass news service reported that the country's space agency, Roscosmos, is investigating the recent rocket failure and is expected to present an initial report to the Russian Deputy Prime Minister Dmitry Rogozin soon.

Roscosmos chief Vladimir Popovin said earlier that an engine failure was the most likely cause of the Dec. 23 rocket crash, though more investigation was needed to be sure.

The Soyuz 2 rocket launch, which was overseen by the European launch provider Arianespace via its Russian affiliate Starsem, carried six second-generation Globalstar satellites, each weighing 1,543 pounds (700 kilograms), into an initial 572-mile (920-km) orbit.

The mission is the third in a series of Globalstar satellite launches, with twelve satellites launched on two earlier missions. Another six satellites will be launched for Globalstar in 2012, Arianespace officials said.

UK Scientists find New Extreme Life at Deep Sea Volcanic Vent - Yeti Crabs

British scientists have discovered an astonishing range of creatures living in one of the most inhospitable regions of the deep sea.

Researchers have been exploring and taking samples from the "Dragon Vent" in the south-west Indian Ocean when they found yeti crabs, sea cucumbers and snails living around the volcanic underwater vents.

According to Dr. Jon Copley, a marine biologist at the University of Southampton who led the expedition said the animals are unique to the region and hasn't been seen in neighboring parts of the ocean.

"We found a new type of yeti crab. Yeti crabs are known at vents in the Eastern Pacific and there are two species described so far, but they have very long, hairy arms - ours have short arms and their undersides are covered in bristles.

They're quite different to the ones that are known from the Pacific," said Copley. "This is the first time a Yeti crab has been seen in the Indian Ocean."

The team also found sea cucumbers, vent shrimps and scaly-foot snails. Sea cucumbers have been previously found at deep sea vents in the Eastern Pacific. This is the first time they've been seen at vents in the Indian Ocean.

Deep-sea vents are fissures in the ocean floor that spew out hot, mineral-rich water. Despite the high temperatures, many species thrive at hydrothermal vents.

The Southampton team were interested in the vents on the South West Indian Ridge because they link back to the Mid Atlantic Ridge and the Central Indian Ridge where deep sea life has been recorded.

This part of the volcanic ridge is also unusual because it's less volcanically active so hydrothermal vents are fewer and more scattered.

The expedition set off from Cape Town on November 7 and returned to South Africa on December 21. The team explored the Dragon Vent for three days and took hundreds of samples of 17 different creatures.

The specimens are now being examined through morphological and genetic testing to determine if they are new species.

Exploring the hydrothermal vents are important because they offer a variety of species that have never been seen before.

"Just like the 19th century naturalists used to go to the Galápagos and other islands to find species there that are different to elsewhere and then use that to understand patterns of dispersal of dispersal and evolution, we can use deep-sea vents to do the same things beneath the waves," Copley said.

"And we need to do that because the exploitation of the deep ocean is overtaking its exploration. We're fishing in deeper and deeper waters, oil and gas is moving into deeper waters and now there's mining starting to take place in deep waters.

We need to understand how species disperse and evolve in the deep oceans if we're going to make responsible decisions about managing their resources."

Volcano Eruption in Cleveland Alaska sparks Airline Alerts

Scientists raised the alert level for trans-pacific commercial air traffic on Thursday, based on the satellite images of the Cleveland volcanic eruption in Alaska's Aleutian Islands.

Satellite images at 4:02 a.m. (Alaska time) showed Cleveland Volcano had spewed ash 15,000 feet into the air in a cloud that moved east-southeast, the Associated Press reported the Alaska Volcano Observatory as saying.

Though the eruption is small and not expected to pose any threat to the big airlines at this point in time, scientists have increased the alert level from yellow to orange, which represents an increased potential of eruptions with or without ash emissions.

The airline industry had already been on alert as the ash emissions could cause disruptions for the air traffic once it reached the level of 20,000 feet. Earlier in July, satellite images showed lava build up in the crater and accumulation in the form of a dome.

The Cleveland Mountain is situated on an uninhabited Chuginadak Island and is a 5,675-foot peak.

Thursday, December 29, 2011

China lays out Aggressive five-year space plans

In a white paper outlining its ambitious space programme's five-year plan, the China National Space Administration (CNSA) said the Long March-5 rockets "will use non-toxic and pollution-free propellant".

Speaking at press briefing outlining the paper, CNSA spokesman Zhang Wei said the rockets would be capable of placing 25-tonne payloads into near-Earth orbit.

China holds up its space programme as a symbol of the nation's growing global stature and technical expertise, and of the ruling Communist Party's success in turning around the fortunes of the once poverty-stricken nation.

Morris Jones, an independent space expert based in Sydney, told AFP the announcement was significant.

"It's impressive that China's reached that stage with this next round of heavy-lift vehicles, so crucial to reaching their goal of building a space station by 2020," he said.

China's space agency said previously announced plans would go ahead over the next five years, among them establishing a launch pad on the southern island of Hainan, launching lunar orbiters and probes and researching a manned moon landing.

The white paper offered no timetable for plans to launch and dock the Shenzhou IX and X rockets onto China's Tiangong-1 experimental space module in 2012. At least one of these rockets is expected to be manned.

In November, the unmanned Shenzhou VIII spacecraft returned to Earth after completing two space dockings with Tiangong-1 in the nation's first ever hard-to-master "space kiss", bringing together two vessels in high speed orbit.

Appearing to try to allay international concerns about China's potential militarisation of space, the agency said China wanted to "utilise outer space for peaceful purposes" -- a claim Morris disputed.

"No nation that has a respectable major space programme has an entirely peaceful programme," he said, noting China had tested anti-satellite weapons by blowing up one of its own in 2007.

"The world over, space technologies are used for military communications and to deploy spy satellites. China's no different," Jones said.

Echoes from Carinae's great eruption

During the mid 1800's, the well known star η Carinae underwent an enormous eruption becoming for a time, the second brightest star in the sky.

Although astronomers at the time did not yet have the technology to study one of the largest eruptions in recent history in depth, astronomers from the Space Telescope Science Institute recently discovered that light echoes are just now reaching us.

This discovery allows astronomers to use modern instruments to study η Carinae as it was between 1838 and 1858 when it underwent its Great Eruption.

Light echoes have been made famous in recent years by the dramatic example of V838 Monocerotis.

While V838 Mon looks like an expanding shell of gas, what is actually depicted is light reflecting off shells of gas and dust that was thrown off earlier in the star’s life.

The extra distance the light had to travel to strike the shell, before being reflected towards observers on Earth, means that the light arrives later. In the case of η Carinae, nearly 170 years later!

The reflected light has its properties changed by the motion of the material off which it reflects. In particular, the light shows a notable blueshift, telling astronomers that the material itself is traveling 210 km/sec.

This observation fits with theoretical predictions of eruptions similar to the type η Carinae is thought to have undergone. However, the light echo has also highlighted some discrepancies between expectation and observation.

Typically, η Carinae’s eruption is classified as a “supernova impostor”. This title is fitting since the eruptions create a large change in the overall brightness.

However, although these events may release 10% of the total energy of a typical supernova or more, the star remains intact.

The main model to explain such eruptions is that a sudden increase in the star’s energy output causes some of the outer layers to be blown off in an opaque wind.

This shell of material is so thick, that it gives a large increase in the effective surface area from which light is emitted, thereby increasing the overall brightness.

However, for this to happen, models predict that the temperature of the star prior to the eruption needs to be at least 7,000 K.

Analyzing the reflected light from the eruption places the temperature of η Carinae at the time of the eruption at a much lower 5,000 K.

This would suggest that the favored model for such events is incorrect and that another model, involving an energetic blast was (a mini-supernova), may be the true culprit, at least in η Carinae’s case.

Yet this observation is somewhat at odds with observations made in the years following the eruption.

As spectrography came into use, astronomers in 1870 visually noticed emission lines in the star’s spectrum which is more typical in hotter stars.

In 1890, η Carinae had a smaller eruption and a photographic spectrum put the temperature around 6,000 K.

While this may not accurately reflect the case of the Great Eruption, it is still puzzling how the star’s temperature could change so quickly and may also indicate that the favoured model of the opaque-wind model is a better fit for later times or the smaller eruption, which would suggest two different mechanisms causing similar results in the same object on short timescales.

Lasers Measure Earth's Rotation and Wobble

The Earth spins around once every 24 hours on its axis, creating the continuous cycle of day and night but this rotation isn't as straightforward as it sounds: Forces large and small cause the Earth to wobble as it spins. This wobbling can pose a problem for navigation systems like GPS.

Scientists working with lasers and mirrors are refining a new system to track the Earth's rotation and its kinks.

The pull of gravity from the sun and the moon contribute to the planet's wobble.

So do variations in atmospheric pressure, ocean loading and the wind, which change the position of the Earth's axis relative to the surface. Together their effect is called the Chandler wobble, and it has a period of 435 days.

Another force causes the rotational axis to move over a period of a year. This "annual wobble" is due to the Earth's elliptical orbit around the sun.

Between these two effects, the Earth's axis migrates irregularly along a circular path with a radius of up to 20 feet (6 meters).

Pinning down the overall wobble of the planet's rotation is key to keeping certain tracking systems accurate.

Currently, this is now done through a complicated process that involves 30 radio telescopes around the globe that measure the direction between Earth and specific quasars, a type of galaxy that is assumed to be stationary relative to the Earth.

A better system
In the mid-1990s, scientists of Germany's Technische Universitaet Muenchen and Federal Agency for Cartography joined forces with researchers at New Zealand's University of Canterbury to develop a simpler method for tracking the Chandler wobble and annual wobble.

"We also wanted to develop an alternative that would enable us to eliminate any systematic errors," said station director, Karl Ulrich Schreiber. "After all, there was always a possibility that the reference points in space were not actually stationary."

The scientists had the idea of building a ring laser similar to ones used in aircraft guidance systems – only millions of times more exact.

"At the time, we were almost laughed off. Hardly anyone thought that our project was feasible," Schreiber said in a statement.

Yet at the end of the 1990s, work on the world's most stable ring laser got under way at Wettzell Geodetic Observatory, in the Bavarian Forest of southeast Germany.

The installation includes two counter-rotating laser beams that travel around a square path with mirrors in the corners, which form a closed beam path (hence the name "ring laser").

Ring around the laser
When the assembly rotates, the co-rotating light has farther to travel than the counter-rotating light. The beams adjust their wavelengths, causing the optical frequency to change. The scientists can use this difference to calculate the rotational velocity the instrumentation experiences.

"The principle is simple," Schreiber said. "The biggest challenge was ensuring that the laser remains stable enough for us to measure the weak geophysical signal without interference — especially over a period of several months."

With some tweaks to the system, the researchers have succeeded in corroborating the Chandler and annual wobble measurements made from the radio telescopes.

They now aim to make the apparatus even more accurate, enabling them to determine changes in the Earth's rotational axis over a single day.

The scientists also plan to make the ring laser capable of running continuously for a period of years. "In future," Schreiber said, "we want to be able to just pop down into the basement and find out how fast the Earth is accurately turning right now."

Einstein Ring Hubble Image: Cosmic Horseshoe seems to surround Red galaxy

A fortuitous alignment of celestial mechanics has given the Hubble Space Telescope an amazing view of some distant galaxies.

Here, one interesting red galaxy is encircled by a hazy blue horseshoe shape and contains about 10 times the mass of our Milky Way galaxy.

It's actually the blue horsehoe shape that has astronomers talking about this photo.

The horseshoe is actually a distant galaxy that has been magnified and warped into a nearly complete ring by the strong gravitational pull of the massive red galaxy in the foreground.

To see such a so-called Einstein Ring required the fortunate alignment of the foreground and background galaxies, making this object’s nickname "the Cosmic Horseshoe" particularly apt, NASA says.

NASA CAssini: Snaps Amazing Photos of Saturn Moon - Titan, Enceladus & Dione

Saturn's largest moon, Titan, passes in front of the planet and its rings in this true colour snapshot from NASA's Cassini spacecraft. 

This view looks toward the northern, sunlit side of the rings from just above the ring plane. 

It was taken on May 21, 2011, when Cassini was about 1.4 million miles (2.3 million kilometers) from Titan.
CREDIT: NASA/JPL-Caltech/Space Science Institute
Titan has a thick, nitrogen-rich atmosphere that shrouds the frigid body in a soupy brown haze. Complex organic molecules — the carbon-containing building blocks of life as we know it — swirl about in this atmosphere. 

The huge moon also has a hydrocarbon-based weather system, with methane rain falling from the sky and pooling in liquid-methane lakes. Astrobiologists speculate that Titan may be one of the best places in the solar system to search for life beyond Earth.

NASA's Cassini spacecraft has captured stunning shots of three of Saturn's moons, showcasing the diversity and beauty of the ringed planet's natural satellites.

The Cassini probe recently beamed home photos of Titan, Dione and Enceladus, three of Saturn's six largest moons. The giant planet has 62 known satellites, but most of them are small, rocky moonlets too small to be rounded by their own gravity.

One of the newly released photos shows Titan passing in front of Saturn and its rings. Titan is the ringed planet's largest satellite; at 3,200 miles (5,150 kilometers) wide, it's nearly 1.5 times bigger than Earth's moon.

NASA's Cassini spacecraft obtained this unprocessed image on Dec. 12, 2011. The camera was pointing toward Saturn's moon Dione from approximately 69,989 miles (112,636 kilometers) away.
CREDIT: NASA/JPL/Space Science Institute

Another of Cassini's new photos shows Dione, an icy, pockmarked globe 698 miles (1,123 km) across. The moon's leading hemisphere is heavily cratered, while its trailing one sports an intricate web of ice cliffs

This photo shows the leading hemisphere of Saturn's moon Enceladus. 

The image was captured on Nov. 6, 2011 by NASA's Cassini spacecraft, when the probe was about 67,700 miles (109,000 kilometers) from the icy moon.
CREDIT: NASA/JPL-Caltech/Space Science Institute

At 319 miles (513 km) across, Enceladus is Saturn's sixth-largest moon — but it may be the gas giant's most intriguing satellite.

Icy geysers erupt from Enceladus' south polar region, fueled by a powerful interior heat source of mysterious origin and scientists think an ocean of salty, liquid water lurks beneath the moon's icy crust, making Enceladus another key target in the search for alien life in our solar system.

The Influencing Machine: Brooke Gladstone on the Media - YouTube

An animated short from the book "The Influencing Machine: Brooke Gladstone on the Media" written by Brooke Gladstone and illustrated by Josh Neufeld. For more information, go to:

Also read more on Books and Graphic novels here Brain Pickings

Wednesday, December 28, 2011

UFO alert as Space debris burns up over Mexico City - YouTube

Handheld video of object breaking up in Earth's atmosphere leads to claims of UFO activities and other non-scientific speculation.

NASA Cassini Views Titan's South pole: Orange and Blue Hazes

This view from NASA's Cassini spacecraft looks toward the south polar region of Saturn's largest moon, Titan, and shows a depression within the moon's orange and blue haze layers near the south pole.

The moon's high altitude haze layer appears blue here; whereas, the main atmospheric haze is orange. 

The difference in colour could be due to particle size of the haze. The blue haze likely consists of smaller particles than the orange haze.

The depressed or attenuated layer appears in the transition area between the orange and blue hazes about a third of the way in from the left edge of the narrow-angle image. 

The moon's south pole is in the upper right of this image. This view suggests Titan's north polar vortex, or hood, is beginning to flip from north to south.

The southern pole of Titan is going into darkness as the sun advances towards the north with each passing day. The upper layer of Titan's hazes is still illuminated by sunlight.

Images taken using red, green and blue spectral filters were combined to create this natural colour view. The images were obtained on Sept. 11, 2011 at a distance of approximately 83,000 miles (134,000 kilometers) from Titan. Image scale is 2,581 feet (787 meters) per pixel.

Image Credit: NASA/JPL-Caltech/Space Science Institute

Ridekick provides an electric boost to regular bicycles

Although some cycling purists may sneer at them, electric bicycles certainly do come in handy when hills need to be climbed on morning commutes, or loads need to be hauled.

E-bikes can be quite expensive, however, plus their motors and batteries make them heavy and clunky when their electric-assist feature isn’t being used.

That’s where the Ridekick kicks in. The motorised trailer quickly hooks onto an existing bicycle, pushing it to speeds of up to 19 mph (30.5 km/h), for a distance of about 12 miles (19 km) per charge. When you want your regular ol’ human-powered bike back, you just unhook it and go.

Ridekick provides an electric boost to regular bicycles - Images

NASA: iPad Visualisation Explorer (US only)

NASA has some of the coolest data around, of course. 

While you can dig around their numerous websites looking for gems, they have made life a lot easier for you and pulled together many of their best work into a free iPad App.

The quality of the visualisations is incredible, and most of them are well annotated/narrated. They add 8-10 new visualizations each month.

NB: Unfortunately, for now, the App is only available in the US but will be available in other areas later in the year.

NASA iPad Visualization Explorer

OPERA: Neutrinos may be tachyons

For a few days in September 2011, it was the biggest story in the world. The little-known OPERA experiment in Gran Sasso, Italy, had just made an electrifying claim - that subatomic particles called neutrinos had travelled faster than the speed of light.

Next year, two experiments - MINOS at Fermilab in Batavia, Illinois, and T2K in Japan (pictured) - will be able to test the claim. If it stands up, how should we meld these misbehaving particles with the rest of physics?
One option is via tachyons, hypothetical particles that are born speeding faster than light. It turns out that the speed limit imposed by Einstein's special theory of relativity isn't so much a cap that nothing can exceed as a barrier that nothing can cross.

Tachyons were dreamed up to illustrate this: particles born faster than light pose no problem for special relativity as long as they spend their whole lives in the fast lane.

Are neutrinos tachyons? One way they might be is if the universe is filled with a field that interacts with particles as they fly through it. If photons have more drag in that field than neutrinos do, then neutrinos would naturally outpace the speed of light.

This idea may feel familiar: light travels slower in glass than in a vacuum, for instance. So the universe might be permeated with a sort of diffuse glass.

If neutrinos do turn out to be tachyons, theorists will still have their work cut out. Though they are born speeding, tachyons interfere with another demand of special relativity: that a particle's behaviour be the same no matter where it is facing or how fast it is going.

Meanwhile, there is no shortage of other theories scrabbling to explain this most astonishing of results.

UK BBC Stargazing Guide - PDF

Human Gets Immersed In Remote Robot's Actions

A group of Japanese roboticists envisions a world where we all use robots to visit friends and family, and represent us in distant work sites.

They are developing a telepresence robot they think will give humans more physical immersion in remote locations.

“Vision is not enough,” said Dzmitry Tsetserukou, an assistant professor at Toyohashi University of Technology’s Advanced Interdisciplinary Electric Research Center.

“We have to provide tactile feedback to make him or her more involved, and also motion feedback so we can feel more like we are human on the robot side.”

Tsetserukou, along with computer science and engineering professor Jun Miura and PhD candidate Sugiyama Junichi, developed a robot called NAVIgoid that enables a human controller to guide it remotely using torso movements, and receive physical feedback from the robot.

The robot was recently demonstrated at the SIGGRAPH conference on computer graphics and interactive techniques in Asia.

Human Gets Immersed In Remote Robot's Actions

ESA ENVISAT Image: Arid Arabia

This Envisat image, acquired on 28 October 2011, shows central Saudi Arabia on the arid Arabian Peninsula. 

The area pictured is on the central plateau, Nejd, which slopes downwards from west to east. 

The dark circle near the centre of the image is the capital city of Riyadh, the nation’s legislative, financial administrative, diplomatic and commercial hub.

Credits: ESA

ISS Expedition 30 Crew New Year's Message - YouTube

A special New Year's message from the Expedition 30 crew members aboard the International Space Station.

ISS Astronauts Celebrate Christmas

NASA astronaut Scott Kelly, commander of Expedition 26 aboard the International Space Station, poses for a holiday photo near the station's miniature Christmas tree.

The six astronauts aboard the International Space Station can't come home for the holidays, but they're doing their best to make the season bright hundreds of miles above Earth's surface.

The spaceflyers have decked the halls of the $100 billion orbiting lab, and — like many of us Earthbound folks — they plan to celebrate Christmas with a party and a feast.

"We've already put up decorations, and we've gathered together all the cards and gifts that our friends and families have sent to us, and we're planning a couple of big meals," NASA astronaut Dan Burbank, commander of the space station's current Expedition 30 mission, said last week. "That'll be great."

NASA SOHO: Solar Storms May Super Charge Aurora

NASA's STEREO-B spacecraft snapped this shot of an Earth-directed coronal mass ejection (CME) erupting from the sun on Dec. 26, 2011. 

The CME can be seen billowing into space to the sun's right.

Particles ejected by recent solar storms are due to slam into Earth over the next few days, possibly causing super-charged northern lights displays and temporary radio blackouts in some areas, experts say.

On Monday (Dec. 26), the sun unleashed a massive eruption of solar plasma known as a coronal mass ejection (CME).

The CME's fast-moving charged particles should squarely strike Earth's magnetic field at about 3:20 p.m. EST (2020 GMT) Wednesday, give or take seven hours, according to the website

The particles from another CME could deliver a glancing blow to our planet a few hours earlier on Wednesday, reported.

The two impacts will likely spawn minor and/or moderate geomagnetic storms at high latitudes on Wednesday and Thursday.

If they're powerful enough, geomagnetic storms can temporarily disrupt GPS signals, radio communications and power grids.

ESA NASA Hubble telescope image: Elliptical Galaxy

This diffuse-looking galaxy may be the only evidence remaining from an ancient collision between two galaxies.

Known as SDSS J162702.56+432833.9, this object is technically catalogued as an elliptical galaxy, but it was likely created during the collision of two spiral galaxies, astronomers say.

This image was taken by the Hubble Space Telescope. Some ribbons of dust notably obscure parts of the conglomerated galaxy's central, bluish region. Those dust lanes could be remnants of the spiral arms of the recently departed galaxies.

NASA Fermi Tycho Supernova: Cosmic Mystery

Gamma rays detected by NASA's Fermi space telescope show that the remnant of Tycho's supernova shines in the highest-energy form of light. 

This portrait of the shattered star includes gamma rays (magenta), X-rays (yellow, green, and blue), infrared (red) and optical data.

CREDIT: Gamma ray, NASA/DOE/Fermi LAT Collaboration; X-ray, NASA/CXC/SAO; Infrared, NASA/JPL-Caltech; Optical, MPIA, Calar Alto, O. Krause et al. and DSS

A well-known exploded star that is pumping out powerful gamma rays may be the celestial smoking gun astronomers have in the search for the origins of some of the fastest-moving particles in the universe, a new study reports.

NASA's Fermi space telescope has detected gamma rays — the highest-energy form of light — emanating from the shattered husk of Tycho's supernova, a star that exploded in 1572.

The find could help astronomers pinpoint the origin of cosmic rays, super-speedy subatomic particles that crash constantly into Earth's atmosphere, researchers said.

NASA MODIS Image: New Island forming in Red Sea

An eruption occurred in the Red Sea in December 2011. According to news reports, fishermen witnessed lava fountains reaching up to 30 meters (90 feet) tall on December 19.

The Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra and Aqua satellites observed plumes on December 20 and December 22.

Meanwhile, the Ozone Monitoring Instrument (OMI) on NASA’s Aura satellite detected elevated levels of sulphur dioxide, further indicating an eruption.

The activity in the Red Sea included more than an eruption. By December 23, 2011, what looked like a new island appeared in the region.

The Advanced Land Imager (ALI) on NASA’s Earth Observing-1 (EO-1) satellite captured these high-resolution, natural-color images on December 23, 2011 (top), and October 24, 2007 (bottom).

The image from December 2011 shows an apparent island where there had previously been an unbroken water surface.

A thick plume rises from the island, dark near the bottom and light near the top, perhaps a mixture of volcanic ash and water vapor.

The volcanic activity occurred along the Zubair Group, a collection of small islands off the west coast of Yemen.

Running in a roughly northwest-southeast line, the islands poke above the sea surface, rising from a shield volcano. This region is part of the Red Sea Rift where the African and Arabian tectonic plates pull apart and new ocean crust regularly forms.
  1. References

  2. Bauwens, J. (2011, December 22). Eruption in the Zubair Archipelago, in the southern Red Sea. Accessed December 27, 2011.
  3. Gass, I.G., Mallick, D.I.J., Cox, K.G. (1973). Volcanic islands of the Red Sea. Journal of the Geological Society, 129(3), 275–309.
  4. Global Volcanism Program. (2011, December 20). Weekly volcanic report, 14 December–20 December 2011. Smithsonian Institution. Accessed December 27, 2011.
  5. Global Volcanism Program. Zubair Group. Smithsonian Institution. Accessed December 27, 2011.
  6. Klemetti, E. (2011, December 19). Potential eruption off the coast of Yemen. Eruptions. Accessed December 27, 2011.
  7. U.S. Geological Survey, National Park Service. (1999, January 14). Divergent plate boundaries. Accessed December 27, 2011.
  8. Volcano Discovery. (2011, December 21). Volcanic eruption in the Red Sea (Yemen) reported. Accessed December 27, 2011.
NASA Earth Observatory image created by Jesse Allen, using EO-1 ALI data provided courtesy of the NASA EO-1 team. Caption by Michon Scott.

Tuesday, December 27, 2011

NASA Chandra X-ray Image: Ring of Fire

This composite image shows the central region of the spiral galaxy NGC 4151.

X-rays (blue) from the Chandra X-ray Observatory are combined with optical data (yellow) showing positively charged hydrogen (H II) from observations with the 1-meter Jacobus Kapteyn Telescope on La Palma.

The red ring shows neutral hydrogen detected by radio observations with the NSF's Very Large Array.

This neutral hydrogen is part of a structure near the center of NGC 4151 that has been distorted by gravitational interactions with the rest of the galaxy, and includes material falling towards the center of the galaxy.

The yellow blobs around the red ellipse are regions where star formation has recently occurred.

A recent study shows the X-ray emission probably was caused by an outburst powered by the supermassive black hole located in the white region in the center of the galaxy. Evidence for this idea comes from the elongation of the X-rays running from the top left to the bottom right and details of the X-ray spectrum.

There are also signs of interactions between a central source and the surrounding gas, particularly the yellow arc of H II emission located above and to the left of the black hole.

NGC 4151 is located about 43 million light years away from the Earth and is one of the nearest galaxies that contains an actively growing black hole. Because of this proximity, it offers one of the best chances of studying the interaction between an active supermassive black hole and the surrounding gas of its host galaxy.

Such interaction, or feedback, is recognized to play a key role in the growth of supermassive black holes and their host galaxies. If the X-ray emission in NGC 4151 originates from hot gas heated by the outflow from the central black hole, it would be strong evidence for feedback from active black holes to the surrounding gas on galaxy scales.

This would resemble the larger scale feedback, observed on galaxy cluster scales, from active black holes interacting with the surrounding gas, as seen in objects like the Perseus Cluster.

Image Credits: X-ray: NASA/CXC/CfA/J.Wang et al.; Optical: Isaac Newton Group of Telescopes, La Palma/Jacobus Kapteyn Telescope, Radio: NSF/NRAO/VLA

ESA INTEGRAL deciphers diffuse signature of cosmic-ray electrons

This image shows the entire sky at hard X-ray energies, between 50 and 100 keV, as observed with the Spectrometer on board INTEGRAL (SPI). The image is based on six years worth of data collected with this instrument.

The two main contributions to the emission at these energies are clearly visible: point sources, galactic and extragalactic alike, and diffuse emission. 

Point sources are scattered across the sky, albeit mainly concentrated along the Galactic Plane; the diffuse emission also traces the Galactic Plane and is fainter, at these energies, than the emission arising from point sources.

To study the diffuse emission in great detail and to break it down into the individual physical processes that contribute to it, astronomers need to carefully scrutinise the data and remove the contamination due to point sources. Credits: ESA/INTEGRAL/SPI.

Grail Twin Probe to Study Earth’s Moon Gravity Field

Two spacecrafts are set to enter orbit around Earth's moon over the New Year's weekend, in the latest lunar mission to measure the uneven gravity field and determine what lies beneath the moon' core.

The near-identical Grail spacecraft, short for Gravity Recovery and Interior Laboratory, which skyrocketed from the Florida coast in September, have been independently traveling to their destination and will arrive 24 hours apart.

On New Year's Eve, one of the Grail probes will fire its engine to slow down so that it could be captured into orbit. This move will be repeated by the other the following day.

The chances of the probes overshooting are slim since their trajectories have been precise, engineers said. Getting struck by a cosmic ray may prevent the completion of the engine burn and they won't get boosted into the right orbit.

After it enters orbit, the spacecraft will spend the next two months flying in formation and chasing one another around the moon until they are about 35 miles above the surface with an average separation of 124 miles. However, data collection won't begin until March, astronomers said.

"Both spacecraft have performed essentially flawlessly since launch, but one can never take anything for granted in this business," said mission chief scientist Maria Zuber of the Massachusetts Institute of Technology.

During the probe's orbit, changes in the lunar gravity field will cause them to speed up or slow down, changing the distance between them. Radio signals transmitted by the spacecraft will measure the slight distance gaps, allowing researchers to map the underlying gravity field.

These information can help scientists deduce what's beneath the lunar surface and explain why the far side of the moon is more rugged than the side that faces Earth.

While many new information about the moon is expected from the probes, the possibility of sending astronauts back may not happen soon as the Constellation program was canceled last year by the government.

Officially known as Grail-A and Grail-B, the name of the probes were taken from a contest hosted by NASA several months ago to submit new names. The probes will be christened with the winning names after the second orbit insertion.

China's Beidou GPS Solution

China launched the Beidou Navigation Satellite System on Tuesday, which will reportedly help the country wean its dependence off the U.S. for its popular Global Positioning System (GPS).

Beidou, which is run by the China Aerospace Science and Technology Corp., will provide positioning, navigation and timing services to the country and its "surrounding areas," according to a spokesperson for the new system.

"The Beidou satellite navigation system is a building of our own, operates independently, and is compatible with other shared global satellite navigation systems," said Ran Cheng, spokesperson for the China Aerospace Science and Technology Corp.

"At present, the Beidou satellite navigation system has launched 10 satellites, and built a basic system [for] active positioning and short-message communication services."

In addition to the 10 satellites launched for Beidou so far, China plans to launch six more into orbit in 2012 to bolster accuracy and expand its service to cover most of the Asia-Pacific area.

Beidou, which means "Big Dipper" in Mandarin-Chinese, began construction in 2000 with the goal of providing a fully-realized satellite sytem by 2020. The original system was going to be called Compass, and it was said to leverage about 35 satellites.

The project was mostly overseen by the Chinese military, which controls the Chinese space program, but it will largely be directed at civilians and commercial applications.

Massive Blue Stars: Ambient molecular gas

Credit: Canada-France-Hawaii Telescope/Coelum

Young massive bright blue stars illuminate the ambient molecular gas of NGC 7129 (top right), a spent star formation region in this image posted on Dec. 21.

The star cluster NGC 7132 (lower left) has existed far longer, and already freed itself from a nascent shroud of gas.

Soyuz Rocket Debris Fireball

Astrophotographer Roman Breisch snapped this photo of a fireball created by a re-entering Russian rocket stage over Germany on Dec. 24, 2011. 

The rocket debris was part of a Soyuz rocket that successfully launched a new crew to the International Space Station on Dec. 21.
CREDIT: Roman Breisch

A dazzling fireball that lit up the night sky above Europe in a bright Christmas Eve display was no meteor or comet.

A falling piece of a Russian rocket created the light show to cap the end of its successful mission, scientists say.

The fireball was spotted over several European countries on the evening of Dec. 24. By Christmas Day, astronomers at the Belgium Royal Observatory pinned down the source of the night-sky fireworks.

"The fireball observed above Belgium, the Netherlands, France and Germany on December 24 around 17h30, was the re-entry of the third stage of the Soyuz rocket that transported the Dutch astronaut Andre Kuipers to the International Space Station," observatory officials said in a written update.

The rocket's spent upper stage then fell back to Earth in a fiery re-entry through the atmosphere. But despite the man-made nature of the fireball, it still amazed skywatchers who happened to look up as the rocket debris fell to Earth

Spectacular Christmas Comet Amazes ESO Skywatchers

This photo comes from a time-lapse sequence taken by Gabriel Brammer from ESO just two days ago on 22 December 2011. 

Gabriel was finishing his night shift as support astronomer at the Paranal Observatory when the comet rose over the horizon just before dawn.
CREDIT: G. Brammer/ESO

A stunning comet that survived a recent brush with the sun is amazing astronomers again, this time in dazzling new photos captured just before sunrise over Chile.

The comet Lovejoy may not be the famed Star of Bethlehem, but it still provided a jaw-dropping sight for astronomer Gabriel Brammer, photographed the comet rising ahead of the sun on Dec. 22 at Paranal Observatory in Chile's high Atacama Desert.

Brammer is a support astronomer for the European Southern Observatory (ESO), which runs the Paranal facility. His time-lapse photos of comet Lovejoy show it rising ahead of the sun as the Paranal astronomers fire a laser beam, which serves as a guide star, into the sky. Our Milky Way galaxy and the moon are also visible in the images.

"On the last morning of my shift I tried to try catching it on camera before sunrise," Brammer said in a statement.

"The tail of the comet was easily visible with the naked eye, and the combination of the crescent moon, comet, Milky Way and the laser guide star was nearly as impressive to the naked eye as it appears in the long-exposure photos."

Some young Milky Way stars may be much older

The new analysis shows that stars over a wide range of masses in Upper Scorpius - from slightly more massive than our Sun, up to the mass of the bright star Antares (17 times the mass of our Sun) are giving ages consistent with a mean age of 11 million years.

Low in the south in the summer sky shines the constellation Scorpius and the bright, red supergiant star Antares. Many of the brightest stars in Scorpius, and hundreds of its fainter stars, are among the youngest stars found near the earth, and a new analysis of them may result in a rethinking of both their ages and the ages of other groups of stars.

New research by astrophysicists from the University of Rochester focused on stars in the north part of the constellation, known as Upper Scorpius, which is a part of the Scorpius-Centaurus OB association, one of our best studied groups of young stars and a benchmark sample for investigating the early lives of stars and the evolution of their planet-spawning disks.

The Upper Scorpius stellar group lies roughly 470 light years from Earth.

While those stars have been thought to be just five million years old, the team concludes that those stars are actually more than twice as old, at 11 million years of age. The findings are surprising given Upper Scorpius's status as one of the best-studied samples of young stars in the sky.

The findings by graduate student Mark Pecaut and Assistant Professor Eric Mamajek of Rochester, and Assistant Professor Eric Bubar of Marymount University, were accepted for publication in the Astrophysical Journal.

The scientists came to their conclusions after analyzing hundreds of optical spectra measured with the SMARTS 1.5-meter telescope at Cerro Tololo Inter-American Observatory (CTIO) in Chile, as well as reanalyzing previously published data on the stars.

"We combined our new estimates for the temperatures of the stars based on our spectra, with data on the brightnesses and distances to estimate accurate luminosities," said Pecaut. "Then we used state-of-the-art stellar evolution models to determine the ages."
The Scorpius OB association is a loose group of stars. This group contains many hot, extremely luminous OB-type stars. It is the site of recent star formation.

The stars in such groups are mostly not gravitationally bound but are expanding away from some common center, which presumably marks their birthplace. 

A recent study indicates that the Scorpius association has had 20 supernova explosions over the past 11 million years.

While similar methods were used in the past to calculate ages for some of the Upper Scorpius stars, Pecaut says no previous study has determined independent age estimates for members of the group over such a wide range of stellar masses.

The new analysis shows that stars over a wide range of masses in Upper Scorpius - from slightly more massive than our Sun, up to the mass of the bright star Antares (17 times the mass of our Sun) are giving ages consistent with a mean age of 11 million years.

"For one thing, the distances to the stars are now much more accurately known," said Pecaut. "Also, the newer computer models take into account the rotation of the stars and its effect on the mixing on the star's hydrogen - its nuclear fuel source."

"The first criticism that we heard of the work was that our age estimates for the stars more massive than the Sun in Upper Scorpius disagreed drastically with previously published ages for the smaller stars in the group," said Mamajek.

"However, we think the stellar parameters and models are on much firmer footing for the higher mass stars than for the lowest mass stars.

"The computer models of stars have trouble predicting the correct masses of low-mass stars when they are dynamically measureable, as well as the rate at which the low-mass stars consume their lithium through nuclear reactions.

Soyuz Launch of Proton-M carrier rocket postponed

The launch of a Russian Proton-M carrier rocket with a Dutch telecommunications satellite SES-4 (NSS-14) onboard was called off on Monday due to "technical problems", a spokesman for the Khrunichev State Research and Production Center said.

He said the new date for launch was being discussed. He did not elaborate on the cause of the delay.

The launch would have been the 70th commercial launch of a Proton carrier rocket since 1995 and the 10th launch of this type of carrier rocket this year.

The SES-4 satellite, built by U.S. company Space Systems/Loral for the Dutch operator Ses World Skies, is designed to provide various satellite services to customers in the Middle East, Europe, Africa and Latin America.

Russia has experienced a number of launch mishaps in the past 13 months, including the crash of a Meridian dual purpose satellite shortly after take-off last week.

That incident led the head of Russia's Roscosmos space agency to say the industry was "in crisis."

The rocket failures come on top of the loss of Phobos-Grunt, Russia's most ambitious planetary mission in decades.

It became stuck in Earth orbit after its launch in November and is expected to fall back to Earth in mid-January.

A Siberian resident miraculously escaped serious injury or even death when a fragment of a Russian communication satellite crashed through the roof of his house.

A Meridian satellite that was launched on Friday from the Plesetsk space center in northern Russia on board a Soyuz-2 carrier rocket crashed near the Siberian city of Tobolsk minutes after liftoff.

Eight satellite fragments were found in an area some 100 kilometers from the city of Novosibirsk.

One, a titanium ball of about five kilograms, fell on to the roof of a village house in the Ordyn district.

The house owner, Andrei Krivorukov, had gone out to the yard to fetch firewood minutes before the crash.

A Second Temporary Moon is A Normal Occurrence, Research Says - International Business Times

Research findings show that a second temporary moon is the norm in our planet, noting that what looked like a spent rocket stage which was seen orbiting the Earth in 2006 was in fact asteroid 2006 RH120, a natural satellite like the moon.

According to a team of astrophysicists from Cornell, the 2006 RH120, which measured just a few meters in diameter could be a second temporary moon. By 2007, it left the Earth's orbit in search of a new cosmic companion.

The team from Cornell, astrophysicists Mikael Granvik, Jeremie Vaubaillon, Robert Jedicke, said temporary satellites are a result of the gravitational pull of Earth and the Moon which pull on one another and also pull on anything else in nearby space.

According to reasearchers, among the most common objects that are pulled in by the Earth-Moon system's gravity are near Earth objects (NEOs) which are comets and asteroids that end up in orbit and eventually brought near Earth.

The scientists modeled the way our Earth-Moon system captures these NEOs to understand how often additional moons come and how long stay. Their findings show that the Earth-Moon system captures NEOs quite frequently.

"At any given time, there should be at least one natural Earth satellite of 1-meter diameter orbiting the Earth," the team said. These NEOs orbit the Earth for about ten months, enough time to make about three orbits, before leaving.

If the findings of the study are correct, then chances for a manned mission to an asteroid increase. Now astronauts won't have to go all the way out to an asteroid to learn about the Solar System's early history but they can wait for an asteroid to come near the Earth, researchers said.

Sunday, December 25, 2011

Another Russian Soyuz-2 Rocket Fails to reach Orbit

An unmanned Soyuz-2 rocket carrying a Russian communications satellite lifted off from Russia's Plesetsk space center at 7:08 a.m. EST (1208 GMT), but failed to reach orbit after a third-stage engine failure.

The rocket and its payload crashed in Siberia, according to the Russian state news agency RIA Novosti.

There was no immediate word about whether the Soyuz-2 failure will impact upcoming launches, including a Soyuz flight slated for Wednesday to put six Globalstar mobile communications satellites into orbit.

The engine on the Soyuz-2 rocket lost Friday is different than the one used on the rocket that launches space station cargo and crews, NASA said.

"This is unlikely to have any effect on operations to the International Space Station," said NASA spokesman Joshua Buck.

NASA, Soyuz: New Crew Arrives at International Space Station

A Russian Soyuz capsule arrived at the International Space Station on Friday with a trio of astronauts, bringing the orbital outpost back to full staffing after a failed cargo ship launch in August disrupted flight schedules.

Russian cosmonaut Oleg Kononenko, NASA's Don Pettit and the European Space Agency's Andre Kuipers blasted off from the Baikonur Cosmodrome in Kazakhstan on Wednesday for the space station, a $100 billion research complex that orbits about 240 miles above Earth.

Their two-day trip in the cramped capsule ended at 10:19 a.m. EST (1519 GMT) when the Soyuz slipped into the Earth-facing docking port on the station's Rassvet module.

The docking occurred about three hours after another botched Russian launch, the fifth this year.

An unmanned Soyuz-2 rocket carrying a Russian communications satellite lifted off from Russia's Plesetsk space center at 7:08 a.m. EST (1208 GMT), but failed to reach orbit after a third-stage engine failure.

The rocket and its payload crashed in Siberia, according to the Russian state news agency RIA Novosti.

There was no immediate word about whether the Soyuz-2 failure will impact upcoming launches, including a Soyuz flight slated for Wednesday to put six Globalstar mobile communications satellites into orbit.

The engine on the Soyuz-2 rocket lost Friday is different than the one used on the rocket that launches space station cargo and crews, NASA said.

"This is unlikely to have any effect on operations to the International Space Station," said NASA spokesman Joshua Buck.

The next cargo run to the space station is scheduled for launch on January 25.

At a news conference broadcast on NASA Television following the new crew's arrival, Russian space agency officials acknowledged the country's aerospace industry is in trouble.

"There are problems," Roscosmos chief Vladimir Popovkin said through a translator. "There is aging of many resources. We need to optimize everything. We need to modernize."

"It's also aging of human resources," Popovkin said. "Given the troubles we had in the '90s, quite a lot of people left and nobody came to replace them."

Russian launch troubles kept the space station short-staffed for most of the past three months.

Crew flights to the station were delayed while Russian engineers scrambled to find and fix the cause of a Progress cargo ship engine failure on August 24. The engine is virtually identical to the one used on the Russian Soyuz capsules that ferry crew.

The accident was traced to contamination or a blockage in a fuel line.

Russia beefed up its inspection and quality control systems and resumed flying on October 30.

Russian launch failures this year also claimed a long-awaited mission to return samples from the Martian moon Phobos. The 13-ton Phobos-Grunt spacecraft is expected to re-enter Earth's atmosphere between January 9 and 16.

The newly arrived crew at the space station joined station commander Dan Burbank and two cosmonauts, who have been aboard the outpost since November 16.

"It is so great to have all six crew members on board the space station," said NASA's head of human spaceflight Bill Gerstenmaier.

"This will be an exciting period for the crew. They have many activities over the next several months."

With the return to a six-member crew, the station can resume full-time science operations, including medical research, physics experiments and astronomical observations.

The crew also will begin preparations for the arrival of the first commercial cargo ship.

Space Exploration Technologies, or SpaceX, is scheduled to launch its Falcon 9 rocket and Dragon capsule on February 7 for a trial run to the station.

The debut flight of a second U.S. supplier, Orbital Sciences Corp., is expected later in the year.

Saturday, December 24, 2011

Russian Phobos Grunt satellite debris lands in Cosmonaut Street

Fragments of a Russian satellite that failed to launch properly have landed in a street named after cosmonauts in a remote Siberian village, reports say.

The Meridian communications satellite failed to reach orbit on Friday.

Parts crashed into the Novosibirsk region of central Siberia and were found in the Ordynsk district around 100km (60 miles) south of the regional capital, Novosibirsk.

Residents of Vagaitsevo village said a piece had landed on a house there.

The owner of the house, Andrei Krivoruchenko, said that he heard a huge noise and a crash as the satellite hit the roof.

"I climbed up onto the roof and could not work out what had happened. Then I saw a huge hole in the roof and the metal object," he told Russian state television.

The head of the Ordynsk district, Pavel Ivarovksy, told Russia's Interfax news agency that the damage was being examined by specialists and that the home's owner would be compensated.

The loss of the Meridian satellite ends a disastrous 12 months for Russian space activity with the loss of three navigation satellites, an advanced military satellite, a telecommunications satellite, a probe for Mars and as an unmanned Progress supply ship.

Earlier this month, Russia also failed to launch a Soyuz rocket.

The next Soyuz launch is scheduled for 26 December from the Baikonur Cosmodrome.

Friday, December 23, 2011

NASA WISE Presents a Cosmic Wreath

NASA's Wide-field Infrared Survey Explorer (WISE) mission presents the "Wreath nebula." Though its official name is actually Barnard 3, or IRAS Ring G159.6-18.5, one might picture a wreath in these bright green and red dust clouds. Image credit: NASA/JPL-Caltech/UCLA

Just in time for the holidays, astronomers have come across a new image from NASA's Wide-field Infrared Survey Explorer, or WISE, that some say resembles a wreath. You might even think of the red dust cloud as a cheery red bow, and the bluish-white stars as silver bells.

This star-forming nebula is named Barnard 3. Baby stars are being born throughout the dusty region, while the "silver bell" stars are located both in front of, and behind, the nebula.

The bright star in the middle of the red cloud, called HD 278942, is so luminous that it is likely causing most of the surrounding clouds to glow. The red cloud is probably made of dust that is more metallic and cooler than the surrounding regions.

The yellow-green region poking into the picture from the left like a sprig of holly is similar to the rest of the green "wreath" material, only more dense.

NASA's Jet Propulsion Laboratory, Pasadena, Calif., manages and operates the Wide-field Infrared Survey Explorer for NASA's Science Mission Directorate, Washington. The principal investigator, Edward Wright, is at UCLA.

NASA Messenger: Mercury's magnetic field counteracted by Solar wind

The Messenger space probe - which took this image - has confirmed that the innermost planet has a magnetic field 150 times weaker than that of Earth. Researchers have now found an explanation for this. 

Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington

Mercury, the smallest of the eight planets with a diameter of 4900 kilometres and the closest to the Sun, looks more like the Moon than the Earth from the outside.

It is the only rocky planet that has a global magnetic field like Earth. But why is its magnetic field so much weaker than Earth’s?

Scientists at the Technische Universität Braunschweig and the Max Planck Institute for Solar System Research have now presented a new explanation: the solar wind counteracts Mercury’s internal dynamo and thus weakens its magnetic field.

Planetary magnetic fields are generated by flows in the hot, liquid iron cores of the .

Measurements made by Mariner 10 in 1974/75 showed that Mercury also has a magnetic field. According to the standard models, the dynamo effect in its metal core should generate similar field strengths to those on .

Mercury’s magnetic field is 150 times weaker than that of our planet, however. This has recently been confirmed by the Nasa space probe Messenger.

How can the large discrepancy in the field strength be explained? This question has now been answered by a group headed by Karl-Heinz Glassmeier at the Technische Universität Braunschweig.

The solar wind – a constant stream of charged particles – plays a significant role. At an average distance from the Sun of only 58 million kilometres – around one third of the distance of the Earth – Mercury is much more exposed to these particles.

“We must keep in mind that Mercury stongly interacts with the surrounding solar wind,” says Daniel Heyner, lead author of the article published in Science and doctoral student at the International Max Planck Research School (IMPRS) in Katlenburg-Lindau.

This interaction drives strong electrical currents in the magnetosphere of the planet, whose magnetic fields counteract the internal dynamo effect.

The team’s new computer models show that a dynamo with this type of feedback is actually possible.

“These types of simulation of the dynamo process are the only possibility to sort of look into the iron core and to predict the strength and structure of the magnetic field,” says Johannes Wicht from the Max Planck Institute for Solar System Research, whose model made a significant contribution to the study.

The results show unambiguously that the feedback ultimately causes the weak magnetic field. “The dynamo process in Mercury’s interior is almost nipped in the bud by the interaction,” explains Glassmeier.

The researchers at the TU Braunschweig and the Max Planck Institute for Research are eagerly awaiting the next magnetic field measurements from the Messenger space probe and the observations of the two satellites of the European-Japanese mission BepiColombo.

The mission will carry an instrument developed by the TU Braunschweig. Starting in 2020 the researchers want to measure ’s with great precision.

The new data should allow the confirmation of this fascinating new idea of a dynamo weakened by the .

More information: Daniel Heyner, Johannes Wicht, Natalia Gómez-Pérez, Dieter Schmitt, Hans-Ulrich Auster, Karl-Heinz Glassmeier, Evidence from Numerical Experiments for a Feedback Dynamo Generating Mercury’s Magnetic Field, Science, 23 December 2011. DOI: 10.1126/science.120729

Space Debris: Metallic ball drops on Namibia

A large metallic ball fell out of the sky on a remote grassland in Namibia, prompting baffled authorities to contact NASA and the European space agency.

The hollow ball with a circumference of 1.1 metres (43 inches) was found near a village in the north of the country some 750 kilometres (480 miles) from the capital Windhoek, according to police forensics director Paul Ludik.

Locals had heard several small explosions a few days beforehand, he said.

With a diameter of 35 centimetres (14 inches), the ball has a rough surface and appears to consist of "two halves welded together".

It was made of a "metal alloy known to man" and weighed six kilogrammes (13 pounds), said Ludik.

It was found 18 metres from its landing spot, a hole 33 centimetres deep and 3.8 meters wide.

Several such balls have dropped in southern Africa, Australia and Latin America in the past twenty years, authorities found in an Internet search.

The sphere was discovered mid-November, but authorities first did tests before announcing the find.

Police deputy inspector general Vilho Hifindaka concluded the sphere did not pose any danger.

"It is not an explosive device, but rather hollow, but we had to investigate all this first," he said.

Shadow of the Milky Way: The Dark Rift

Thick dust clouds block our night-time view of the Milky Way, creating what is sometimes called the Dark Rift. 

The fact that, from Earth, the sun aligns with these clouds, or the galactic center, near the winter solstice is no cause for concern. Credit: A. Fujii

One of the most bizarre theories about 2012 has built up with very little attention to facts.

This idea holds that a cosmic alignment of the sun, Earth, the center of our galaxy - or perhaps the galaxy's thick dust clouds - on the winter solstice could for some unknown reason lead to destruction.

Such alignments can occur but these are a regular occurrence and can cause no harm (and, indeed, will not even be at its closest alignment during the 2012 solstice.)

The details are as follows: Viewed far from city lights, a glowing path called the Milky Way can be seen arching across the starry sky. This path is formed from the light of millions of stars we cannot see individually. It coincides with the mid plane of our galaxy, which is why our galaxy is also named the Milky Way.

Thick dust clouds also populate the galaxy. And while infrared telescopes can see them clearly, our eyes detect these dark clouds only as irregular patches where they dim or block the Milky Way's faint glow.

The most prominent dark lane stretches from the constellations Cygnus to Sagittarius and is often called the Great Rift, sometimes the Dark Rift.

Another impressive feature of our galaxy lies unseen in Sagittarius: the galactic center, about 28,000 light-years away, which hosts a black hole weighing some four million times the sun's mass.

The claim for 2012 links these two pieces of astronomical fact with a third - the position of the sun near the galactic center on Dec. 21, the winter solstice for the Northern Hemisphere - to produce something that makes no astronomical sense at all.

As Earth makes its way around the sun, the sun appears to move against the background stars, which is why the visible constellations slowly change with the seasons.

On Dec. 21, 2012, the sun will pass about 6.6 degrees north of the galactic center - that's a distance that looks to the eye to be about 13 times the full moon's apparent size - and it's actually closer a couple of days earlier.

There are different claims about why this bodes us ill, but they boil down to the coincidence of the solstice with the sun entering the Dark Rift somehow portending disaster or the mistaken notion that the sun and Earth becoming aligned with the black hole in the galactic center allows some kind of massive gravitational pull on Earth.

The first strike against this theory is that the solstice itself does not correlate to any movements of the stars or anything in the universe beyond Earth. It just happens to be the day that Earth's North Pole is tipped farthest from the sun.

Second, Earth is not within range of strong gravitational effects from the black hole at the center of the galaxy since gravitational effects decrease exponentially the farther away one gets.

Earth is 93 million miles from the sun and 165 quadrillion miles from the Milky Way's black hole. The sun and the moon (a smaller mass, but much closer) are by far the most dominant gravitational forces on Earth.

Throughout the course of the year, our distance from the Milky Way's black hole changes by about one part in 900 million - not nearly enough to cause a real change in gravity's pull. Moreover, we're actually nearest to the galactic center in the summer, not at the winter solstice.

Third, the sun appears to enter the part of the sky occupied by the Dark Rift every year at the same time, and its arrival there in Dec. 2012 portends precisely nothing.

Enjoy the solstice, by all means, and don't let the Dark Rift, alignments, solar flares, magnetic field reversals, potential impacts or alleged Maya end-of-the-world predictions get in the way.