One of the largest magnetic storms in history quantified: Aurorae covered much of the night sky from the Tropics to the Polar Regions

In early November of this year, aurora borealis were observed at surprisingly low latitudes, as far south as Italy and Texas. Such phenomena indicate the impacts of a solar coronal mass ejection on the Earth's magnetic field and atmosphere. Far more dramatic than this recent light show was, it was nothing compared to a huge solar storm in February 1872. The resulting auroral display from that event ringed the globe and produced auroras observed in sites as close to the equator as Bombay and Khartoum. An international team consisting of scientists from nine counties has now published a detailed study of this historically important event, tracing its solar origin and widespread terrestrial impacts. Telegraph communications were widely disrupted by this storm, but in today's technologically dependent society, such a storm would disrupt power grids and satellite communications. Their findings confirm that such extreme storms are more common than previously thought.

In the modern world, we are increasingly dependent on technological infrastructure such as power grids, communication systems, and satellites.

However, this dependency makes us increasingly vulnerable to the effects of large geomagnetic storms.

"The longer the power supply could be cut off, the more society, especially those living in urban areas, will struggle to cope," Designated Assistant Professor Hayakawa, the lead author of the study, explains.

Such storms could be big enough to knock out the power grid, communication systems, airplanes, and satellites in the worst case.

"Could we maintain our life without such infrastructure?" Hayakawa comments: "Well, let us just say that it would be extremely challenging."

Such extreme storms are rare. In recent studies, two such storms stand out: the Carrington storm in September 1859 and the New York Railroad storm in May 1921.

The new study suggests that another storm, the Chapman-Silverman storm in February 1872, should also be considered as one of these extreme events.

At the time, the storm was big enough to affect the technological infrastructure even in the tropics.

Telegraph communications on the submarine cable in the Indian Ocean between Bombay (Mumbai) and Aden were disrupted for hours.

Similar disturbances were reported on the land line between Cairo and Khartoum.

The multidisciplinary team, consisting of 22 scientists, was led by Nagoya University in Japan (Hisashi Hayakawa), the US National Solar Observatory (Edward Cliver), and the Royal Observatory of Belgium (Frédéric Clette). The 22 researchers used historical records and modern techniques to assess the Chapman-Silverman storm from its solar origin to its terrestrial impacts.

For the solar origin, the group turned to largely forgotten sunspot records from historical archives, especially Belgian and Italian records.

For terrestrial impacts, they used geomagnetic field measurements recorded in places as diverse as Bombay (Mumbai), Tiflis (Tbilisi), and Greenwich to assess temporal evolution and storm intensity.

They also examined hundreds of accounts of visual aurora in different languages caused by the storm.

One of the more interesting aspects of the 1872 storm was that it likely originated in a medium-sized, but complex, sunspot group near the solar disk centre as confirmed by analyses of solar records from Belgium and Italy.

These findings suggest that even a medium-sized sunspot group triggered one of the most extreme magnetic storms in history.

Hayakawa and his colleagues extended their investigations of the historical aurorae by combing through records in libraries, archives, and observatories around the world.

They identified more than 700 auroral records that indicated that the night sky was illuminated by magnificent auroral displays from the polar regions to the tropics (down to ≈ 20° in latitude in both hemispheres).

"Our findings confirm the Chapman-Silverman storm in February 1872 as one of the most extreme geomagnetic storms in recent history. Its size rivalled those of the Carrington storm in September 1859 and the NY Railroad storm in May 1921," Hayakawa said.

"This means that we now know that the world has seen at least three geomagnetic superstorms in the last two centuries. Space weather events that could cause such a major impact represent a risk that cannot be discounted."

Hayakawa said: "Such extreme events are rare. On the one hand, we are fortunate to have missed such superstorms in the modern time. On the other hand, the occurrence of three such superstorms in 6 decades shows that the threat to modern society is real. Therefore, the preservation and analysis of historical records is important to assess, understand, and mitigate the impact of such events."

Read more at Science Daily

Bringing the sun into the lab

Why the Sun's corona reaches temperatures of several million degrees Celsius is one of the great mysteries of solar physics. A "hot" trail to explain this effect leads to a region of the solar atmosphere just below the corona, where sound waves and certain plasma waves travel at the same speed. In an experiment using the molten alkali metal rubidium and pulsed high magnetic fields, a team from the Helmholtz-Zentrum Dresden-Rossendorf (HZDR), a German national lab, has developed a laboratory model and for the first time experimentally confirmed the theoretically predicted behavior of these plasma waves -- so-called Alfvén waves -- as the researchers report in the journal Physical Review Letters.

At 15 million degrees Celsius, the center of our Sun is unimaginably hot. At its surface, it emits its light at a comparatively moderate 6000 degrees Celsius. "It is all the more astonishing that temperatures of several million degrees suddenly prevail again in the overlying Sun's corona," says Dr. Frank Stefani. His team conducts research at the HZDR Institute of Fluid Dynamics on the physics of celestial bodies -- including our central star. For Stefani, the phenomenon of corona heating remains one of the great mysteries of solar physics, one that keeps running through his mind in the form of a very simple question: "Why is the pot warmer than the stove?"

That magnetic fields play a dominant role in heating the Sun's corona is now widely accepted in solar physics. However, it remains controversial whether this effect is mainly due to a sudden change in magnetic field structures in the solar plasma or to the dampening of different types of waves. The new work of the Dresden team focuses on the so-called Alfvén waves that occur below the corona in the hot plasma of the solar atmosphere, which is permeated by magnetic fields. The magnetic fields acting on the ionized particles of the plasma resemble a guitar string, whose playing triggers a wave motion. Just as the pitch of a strummed string increases with its tension, the frequency and propagation speed of the Alfvén wave increases with the strength of the magnetic field.

"Just below the Sun's corona lies the so-called magnetic canopy, a layer in which magnetic fields are aligned largely parallel to the solar surface. Here, sound and Alfvén waves have roughly the same speed and can therefore easily morph into each other. We wanted to get to exactly this magic point -- where the shock-like transformation of the magnetic energy of the plasma into heat begins," says Stefani, outlining his team's goal.

A dangerous experiment?

Soon after their prediction in 1942, the Alfvén waves had been detected in first liquid-metal experiments and later studied in detail in elaborate plasma physics facilities. Only the conditions of the magnetic canopy, considered crucial for corona heating, remained inaccessible to experimenters until now. On the one hand, in large plasma experiments the Alfvén speed is typically much higher than the speed of sound. On the other hand, in all liquid-metal experiments to date, it has been significantly lower. The reason for this: the relatively low magnetic field strength of common superconducting coils with constant field of about 20 tesla.

But what about pulsed magnetic fields, such as those that can be generated at the HZDR's Dresden High Magnetic Field Laboratory (HLD) with maximum values of almost 100 tesla? This corresponds to about two million times the strength of the Earth's magnetic field: Would these extremely high fields allow Alfvén waves to break through the sound barrier? By looking at the properties of liquid metals, it was known in advance that the alkali metal rubidium actually reaches this magic point already at 54 tesla.

But rubidium ignites spontaneously in air and reacts violently with water. The team therefore initially had doubts as to whether such a dangerous experiment was advisable at all. The doubts were quickly dispelled, recalls Dr. Thomas Herrmannsdörfer of the HLD: "Our energy supply system for operating the pulse magnets converts 50 megajoules in a fraction of a second -- with that, we could theoretically get a commercial airliner to take off in a fraction of a second. When I explained to my colleagues that a thousandth of this amount of chemical energy of the liquid rubidium does not worry me very much, their facial expressions visibly brightened."

Pulsed through the magnetic sound barrier

Nevertheless, it was still a rocky road to the successful experiment. Because of the pressures of up to fifty times the atmospheric air pressure generated in the pulsed magnetic field, the rubidium melt had to be enclosed in a sturdy stainless steel container, which an experienced chemist, brought out of retirement, was to fill. By injecting alternating current at the bottom of the container while simultaneously exposing it to the magnetic field, it was finally possible to generate Alfvén waves in the melt, whose upward motion was measured at the expected speed.

The novelty: while up to the magic field strength of 54 tesla all measurements were dominated by the frequency of the alternating current signal, exactly at this point a new signal with halved frequency appeared. This sudden period doubling was in perfect agreement with the theoretical predictions. The Alfvén waves of Stefani's team had broken through the sound barrier for the first time. Although not all observed effects can yet be explained so easily, the work contributes an important detail to solving the puzzle of the Sun's corona heating. For the future, the researchers are planning detailed numerical analyses and further experiments.

Read more at Science Daily

Bottling the world's coldest plasma

 Rice University physicists have discovered a way to trap the world's coldest plasma in a magnetic bottle, a technological achievement that could advance research into clean energy, space weather and astrophysics.

"To understand how the solar wind interacts with the Earth, or to generate clean energy from nuclear fusion, one has to understand how plasma -- a soup of electrons and ions -- behaves in a magnetic field," said Rice Dean of Natural Sciences Tom Killian, the corresponding author of a published study about the work in Physical Review Letters.

Using laser-cooled strontium, Killian and graduate students Grant Gorman and MacKenzie Warrens made a plasma about 1 degree above absolute zero, or approximately -272 degrees Celsius, and trapped it briefly with forces from surrounding magnets. It is the first time an ultracold plasma has been magnetically confined, and Killian, who's studied ultracold plasmas for more than two decades, said it opens the door for studying plasmas in many settings.

"This provides a clean and controllable testbed for studying neutral plasmas in far more complex locations, like the sun's atmosphere or white dwarf stars," said Killian, a professor of physics and astronomy. "It's really helpful to have the plasma so cold and to have these very clean laboratory systems. Starting off with a simple, small, well-controlled, well-understood system allows you to strip away some of the clutter and really isolate the phenomenon you want to see."

That's important for study co-author Stephen Bradshaw, a Rice astrophysicist who specializes in studying plasma phenomena on the sun.

"Throughout the sun's atomosphere, the (strong) magnetic field has the effect of altering everything relative to what you would expect without a magnetic field, but in very subtle and complicated ways that can really trip you up if you don't have a really good understanding of it," said Bradshaw, an associate professor of physics and astronomy.

Solar physicists rarely get a clear observation of specific features in the sun's atmosphere because part of the atmosphere lies between the camera and those features, and unrelated phenomena in the intervening atmosphere obscures what they'd like to observe.

"Unfortunately, because of this line-of-sight problem, observational measurements of plasma properties are associated with quite a lot of uncertainty," Bradshaw said. "But as we improve our understanding of the phenomena, and crucially, use the laboratory results to test and calibrate our numerical models, then hopefully we can reduce the uncertainty in these measurements."

Plasma is one of four fundamental states of matter, but unlike solids, liquids and gases, plasmas aren't generally part of everyday life because they tend to occur in very hot places like the sun, a lightning bolt or candle flame. Like those hot plasmas, Killian's plasmas are soups of electrons and ions, but they're made cold by laser-cooling, a technique developed a quarter century ago to trap and slow matter with light.

Killian said the quadrupole magnetic setup that was used to trap the plasma is a standard part of the ultracold setup that his lab and others use to make ultracold plasmas. But finding out how to trap plasma with the magnets was a thorny problem because the magnetic field plays havoc with the optical system that physicists use to look at ultracold plasmas.

"Our diagnostic is laser-induced fluorescence, where we shine a laser beam onto the ions in our plasma, and if the frequency of the beam is just right, the ions will scatter photons very effectively," he said. "You can take a picture of them and see where the ions are, and you can even measure their velocity by looking at the Doppler shift, just like using a radar gun to see how fast a car is moving. But the magnetic fields actually shift around the resonant frequencies, and we have to disentangle the shifts in the spectrum that are coming from the magnetic field from the Doppler shifts we're interested in observing."

That complicates experiments significantly, and to make matters even more complicated, the magnetic fields change dramatically throughout the plasma.

"So we have to deal with not just a magnetic field, but a magnetic field that's varying in space, in a reasonably complicated way, in order to understand the data and figure out what's happening in the plasma," Killian said. "We spent a year just trying to figure out what we were seeing once we got the data."

The plasma behavior in the experiments is also made more complex by the magnetic field. Which is precisely why the trapping technique could be so useful.

"There is a lot of complexity as our plasma expands across these field lines and starts to feel the forces and get trapped," Killian said. "This is a really common phenomenon, but it's very complicated and something we really need to understand."

One example from nature is the solar wind, streams of high-energy plasma from the sun that cause the aurora borealis, or northern lights. When plasma from the solar wind strikes Earth, it interacts with our planet's magnetic field, and the details of those interactions are still unclear. Another example is fusion energy research, where physicists and engineers hope to recreate the conditions inside the sun to create a vast supply of clean energy.

Killian said the quadrupole magnetic setup that he, Gorman and Warrens used to bottle their ultracold plasmas is similar to designs that fusion energy researchers developed in the 1960s. The plasma for fusion needs to be about 150 million degrees Celsius, and magnetically containing it is a challenge, Bradshaw said, in part because of unanswered questions about how the plasma and magnetic fields interact and influence one another.

"One of the major problems is keeping the magnetic field stable enough for long enough to actually contain the reaction," Bradshaw said. "As soon as there's a small sort of perturbation in the magnetic field, it grows and 'pfft,' the nuclear reaction is ruined.

Read more at Science Daily

Central mysteries of solar physics

An international team of scientists, including three researchers from New Jersey Institute of Technology (NJIT), has shed new light on one of the central mysteries of solar physics: how energy from the Sun is transferred to the star's upper atmosphere, heating it to 1 million degrees Fahrenheit and higher in some regions, temperatures that are vastly hotter than the Sun's surface.

With new images from NJIT's Big Bear Solar Observatory (BBSO), the researchers have revealed in groundbreaking, granular detail what appears to be a likely mechanism -- jets of magnetized plasma known as spicules that spurt like geysers from the Sun's upper atmosphere into the corona.

In a paper published in the journal Science, the team describes key features of jet-like spicules that are in solar terms small-scale plasma structures, between 200 and 500 kilometers wide, that erupt continuously across the Sun's expanse. The researchers also, for the first time, show where and how the jets are generated and the paths they travel, at speeds of around 100 kilometers per second in some cases, into the corona.

"Unprecedented high-resolution observations from BBSO's Goode Solar Telescope clearly show that when magnetic fields with opposite polarities reconnect in the Sun's lower atmosphere these jets of plasma are powerfully ejected," said solar physicist Wenda Cao, BBSO's director and an author of the paper.

He added, "This is the first time we've seen direct evidence of how spicules are generated. We have tracked these dynamic features in the H-alpha spectral line down to their foot points, measured the magnetic fields at their foot point, captured the migration of the emerging magnetic elements and verified their interaction with existing magnetic fields of the opposite polarity."

Images captured in the extreme ultraviolet (EUV) spectrum by NASA's Solar Dynamics Observatory spacecraft were used to track the transportation of energy in the corona. These observations showed that it is also common for spicules to be heated to typical coronal temperatures.

Invisible to the human eye except when it appears briefly as a fiery halo of plasma during a solar eclipse, the corona remains a puzzle even to scientists who study it closely. Beginning 1,300 miles from the star's surface and extending millions more in every direction, it is more than a hundred times hotter than lower layers much closer to the fusion reactor at the Sun's core.

Solving what astrophysicists call one of the greatest challenges for solar modeling -- determining the physical mechanisms that heat the upper atmosphere -- requires high-resolution images that were not available until BBSO's 1.6-meter telescope, the largest operating solar telescope in the world, began capturing images a decade ago.

Scientists at Big Bear have also captured the first high-resolution images, for example, of magnetic fields and plasma flows originating deep below the Sun's surface, tracing the evolution of sunspots and magnetic flux ropes through the chromosphere before their dramatic appearance in the corona as flaring loops.

Read more at Science Daily

A Hole in the Sun Could Unleash New Year's Fireworks

Like watching an ominous storm brew on the horizon, solar astronomers have spied a large coronal hole emerge deep inside the sun's magnetized atmosphere (known as the corona), signalling that turbulent space weather is possibly headed our way. But don't prepare your tornado shelters or board up your windows, this kind of storm will have minimal impacts on the ground and could actually generate some timely auroral fireworks to kick of 2017 in style.

As reported by Spaceweather.com, NASA's Solar Dynamics Observatory (SDO) has been tracking a dark region in the sun's lower corona rotate into view. Coronal holes are associated with streams of fast-moving superheated plasma that emerges from the sun's interior and then accelerated into space, following magnetic fields that reach from the lower corona and flow out into interplanetary space.

As the sun rotates, it sweeps magnetic streams out into the solar system, like a spinning garden sprinkler, sending these high-energy particles along with it as the fast solar wind. The sun also sweeps out slow-moving streams of plasma (the slow solar wind), which can create a barrier to these fast streams. The regions where these two streams interact are known as co-rotating interaction regions (CIRs) and they are known to cause plasma to "bunch up", creating dense flows of shocked plasma. And as we are basically staring into a fast stream's sprinkler's head, a CIR is likely on its way.

The SDO observes the sun's hot atmosphere through many different filters that are sensitive to different wavelengths of light. Each wavelength represents a different plasma temperature and in the observation above, the SDO is looking at plasma that is glowing at a temperature of 2.25 million Fahrenheit (1.25 million Kelvin). At this wavelength, coronal holes become obvious — they appear dark as the density of plasma is very low (as the particles are being lost to space very quickly); bright regions are dense with plasma at this temperature as they are trapped in closed magnetic field lines, features known as coronal loops.

Typically, solar wind particles in fast streams coming from coronal holes take a couple of days to travel from the sun to the Earth, so by using these SDO observations, solar physicists can make predictions as to what might happen when a CIR washes over Earth. Although we can expect more dramatic impacts if the sun unleashed an explosive event, like a coronal mass ejection or solar flare, CIRs are known to intensify space weather conditions, likely sparking auroras.

When solar particles hit our planet's powerful magnetic field, these electrically charged particles (known as ions) are deflected by the global magnetosphere and channeled to polar regions where Earth's magnetic field passes into the planet's crust. When a solar storm hits, these particles rain through the Earth's atmosphere at high latitudes, hitting atmospheric gases. This is when the magic happens. As solar plasma hits the atmosphere, light is produced. This light is known as the aurora. And as we are seeing this coronal hole emerge now, it could mean auroral activity on New Year's Eve.

Read more at Discovery News

Einstein's Theory Just Put the Brakes on the Sun's Spin

Although the sun is our nearest star, it still hides many secrets. But it seems that one solar conundrum may have been solved and a theory originally proposed in 1905 by Albert Einstein could be at the root of it all.

Twenty years ago, solar astronomers realized that the uppermost layer of the sun rotates slower than the rest of the sun's interior. This is odd. It is well known the sun rotates faster at its equator than at its poles — a phenomenon known as "differential rotation" that drives the sun's 11-year solar cycle — but the fact that the sun has a sluggish upper layer has been hard to understand. It's as if there's some kind of force trying to hold it in place while the lower layers churn below it.

Now, researchers from University of Hawaii Institute for Astronomy (IfA), Brazil, and Stanford University may have stumbled on an answer and it could all be down to fundamental physics. It seems that the light our sun generates has a braking effect on the sun's surface layers.

"The sun won't stop spinning anytime soon, but we've discovered that the same solar radiation that heats the Earth is 'braking' the sun because of Einstein's Special Relativity, causing it to gradually slow down, starting from its surface," said Jeff Kuhn, of IfA Maui, in a statement.

Special relativity predicts that photons, which carry the electromagnetic force (i.e. light), also carry a tiny amount of momentum. If you have enough photons travelling away from an object, they will carry away a large amount of momentum. In the case of the sun's 4 billion year lifetime, the surface has lost a lot of momentum to photons, causing a slowdown of the uppermost 5 percent of the sun. This mechanism, called the Poynting-Robertson effect, has been observed in interplanetary dust, which feels the drag of the sun's radiation, causing it to fall from the asteroid belt into the inner solar system.

What affects dust inevitably affects the soup of super-heated gas in the sun's upper layers and, over its 5 billion year lifetime, the drag caused by photons being emitted from the sun has created a measurable and, until now, mysterious effect.

Using several years of data from NASA's Solar Dynamics Observatory (SDO), the researchers were able to measure waves traveling through the sun to precisely measure the size of the layer that is experiencing this slowdown. The technique, known as "helioseismology," is very similar to measuring the seismic waves travelling through the Earth to measure the strength of an earthquake. The material these seismic waves travel through changes the waves so seismologists can "see" underground.

Though the sun isn't a solid planet made from rock and metal, its dense plasma interior also allows waves to travel, creating oscillations on the surface that can be measured. Helioseismology therefore allows astronomers to "see" into our nearest star, revealing many details about its interior that may not be obvious on the surface. And in this case, by using helioseismology and studying the sun's magnetic field passing from space into the sun's interior, we can gauge how much of a drag Einstein's special relativity has had on the sun's surface.

"This is a gentle torque that is slowing it down, but over the Sun's 5 billion year lifetime it has had a very noticeable influence on its outer 35,000 kilometers [22,000 miles]," said Kuhn. These findings have accepted for publication in the journal Physical Review Letters and can be previewed on the arXiv pre-print service.

Read more at Discovery News

Black Hole Hunter Probes Our Psychedelic X-Ray Sun

A space telescope designed to look into the furthest-most reaches of space at some of the most energetic phenomena in the known universe has, once again, been turned to face our nearest star, producing a rare and beautiful insight to our X-ray sun.

Usually, NASA’s Nuclear Spectroscopic Telescope Array, or NuSTAR, would be looking at relativistic jets of material blasting from black hole behemoths millions to billions the mass of the sun, or the superheated hearts of supernovae, but in a follow-up to arguably one of the most beautiful space images ever created, astrophysicists have created a full-disk portrait of the high-energy X-ray-generating processes in the sun’s corona.

In this stunning image, NuSTAR X-ray observations (in blue) have been superimposed over ultraviolet observations made by NASA’s Solar Dynamics Observatory (SDO) and lower-energy X-rays imaged by the Japanese Hinode observatory to produce a wonderfully psychedelic solar view.

The solar corona — the sun’s multi-million degree “atmosphere” — is a hothouse of magnetically-dominated processes and the focus of one of the most enduring mysteries in stellar science. Put simply, the corona is too hot; the tenuous plasma that extends from the sun’s photosphere (colloquially known as the sun’s “surface”) can be millions of degrees Kelvin (Celsius) hotter than the sun’s uppermost layers. Classical thermodynamics shouldn’t allow this to happen — it doesn’t, for example, get hotter the further you move your hand away from an open flame.

But solar scientists are hot on the trail of finding out what mysterious coronal processes must be going on and these unique observations by NuSTAR may be able to help out.

One coronal heating mechanism focuses on small-scale flaring events called nanoflares. These flares may be small on solar scales, but they are thought to dump huge quantities of energy into the corona, heating it. Current observatories cannot see individual nanoflares as they are too small to be resolved, but they do generate X-ray emissions right in the observing threshold for NuSTAR, so the mission should be able to spot their high-energy X-rays.

As the sun is still fairly active in its 11-year solar cycle after reaching solar maximum in 2013, the mission has picked out some regions in the sun’s atmosphere rumbling with X-ray activity, with “hotspots” over active regions bustling with microflares and, possibly, nanoflares.

“We can see a few active regions on the sun in this view,” said Iain Hannah, of the University of Glasgow, in a press release. “Our sun is quietening down in its activity cycle, but still has a couple of years before it reaches a minimum.”

Hannah presented this observation on Wednesday at the National Astronomy Meeting in Llandudno, Wales.

To measure a definitive nanoflare signal, however, the sun needs to calm down to a more quiescent state, a phase that solar astronomers are anticipating over the next few years as it approaches solar minimum. A slowdown in magnetic activity will reduce the number of active regions and quench powerful flaring activity. In this quiescent state, the high-energy X-ray nanoflare emissions could be detected from the noise.

“We still need the sun to quieten down more over the next few years to have the ability to detect these events,” said Hannah.

Read more at Discovery News

Earth's Magnetic Shield Buffered Powerful Solar Storm

A giant eruption from the sun that scientists thought would hit Earth in 2014 missed because the sun's magnetic field channeled it away from the planet in an unexpected way, researchers say.

This finding could lead to better modeling and forecasting of disruptive solar storms in the future, the scientists added.

Solar eruptions, known as coronal mass ejections, are the hurricanes of space weather. These explosions can drive on the order of a billion tons of super-hot matter out from the sun.

When coronal mass ejections hit Earth, they can trigger major disturbances known as geomagnetic storms, which can in turn wreak massive havoc. For example, in 1989, a coronal mass ejection blacked out the entire Canadian province of Quebec within seconds, damaging transformers as far away as New Jersey, and nearly shutting down U.S. power grids from the mid-Atlantic through the Pacific Northwest.

To forecast the hazards that coronal mass ejections might pose to assets both on the ground and in space, researchers need to know where they are headed. However, much remains unknown about what guides their direction, and therefore whether they might hit Earth.

For instance, on Jan. 7, 2014, astronomers spotted a very fast coronal mass ejection headed toward Earth, one traveling more than 5.3 million mph (8.6 million km/h). Scientists expected it would trigger a strong geomagnetic storm, one that could spark radio navigation problems and set off alarms in power systems. However, the worst of the eruption missed Earth, and no geomagnetic storm followed.

To learn more about why this coronal mass ejection missed Earth, scientists collected data from 7 different space missions that saw the explosion. They modeled the evolution of the eruption from the sun, up to Earth, and as far as Mars, where it was detected by the Curiosity rover.

Instead of hitting Earth, the coronal mass ejection was slanted toward a zone below and behind Earth. The researchers suggest it got channeled this way by powerful magnetic fields originating from a region nearby on the sun.

"Very fast and possibly havoc-creating coronal mass ejections can erupt in a very different direction than indicated by the position of their source region on the sun,"study lead author Christian Möstl, a heliophysicist at the Austrian Academy of Sciences in Graz, told Space.com.

Potential applications of this research include better real-time predictions of space weather. "Forecasters should always look at the magnetic fields of the solar corona surrounding a big eruption to see how likely such a strongly channeled eruption is," Möstl said.

Read more at Discovery News