Extreme Solar Storm Could Cause Widespread Disruptions on Earth
By Miriam Kramer, SPACE.com
May 21, 2013
If an extreme solar storm
aimed at the Earth hits in just the right way, it could put
interconnected electrical grids around the world at serious risk,
experts say.
"What [a solar storm] can do — even if it isn't causing a continental-scale outage — it can really cause a regional blackout," said Daniel Baker, director of the Laboratory for Atmospheric and Space Physics at the University of Colorado. "Imagine something like, for example, Superstorm Sandy. Imagine that kind of severe storm — but causing regional outages for weeks. Living without power really cascades and propagates in remarkable ways throughout our society."
As the sun reaches the peak in its 11-year cycle this year, scientists
expect that active regions of the star — known as sunspots — will erupt,
flinging streams of charged particles out into the solar system. Relatively minor storms can also create temporary radio blackouts and disrupt GPS navigation.
However, this doesn't necessarily mean that all solar eruptions will impact the Earth. Most coronal mass ejections
are not aimed toward the planet, and instead shoot out harmlessly into
other parts of the solar system. But once every century or so, an
extreme solar storm is expected to impact the Earth, Baker told SPACE.com.
These kinds of storms from the sun are notoriously difficult to predict. Experts understand the general conditions under which solar storms occur, but it's hard to forecast just how powerful the storm will be, said Karel Schrijver, a solar scientist and fellow at Lockheed Martin.
"A [coronal mass ejection] takes two to four days to get to the Earth, so if we had more observational resources, to map its motion — and if we had some measurements of the structure of what's going to hit you — there are ways by which we can certainly improve the forecast," Schrijver told SPACE.com.Scientists can use sun-observing satellites like NASA's Solar Dynamics Observatory to monitor, and possibly forecast, solar weather that could be heading toward the planet, Schrijver said.
"There's a lot of space to be explored in terms of computer models that are becoming ever more powerful," Schrijver added. "The heliophysics division at NASA has a wonderful fleet of observatories that looks at the space between the sun and the Earth and the Earth's environment."
Fallout from Huge Solar Flare Sideswipes Earth Today
SPACE.comMay 17, 2013
A huge explosion on the sun will deal Earth a glancing blow today (May 17) but should not pose a threat to the planet, scientists say.
The sun storm erupted late Tuesday (May 14) during a powerful solar flare — the fourth unleashed by a single sunspot in just 48 hours — and hurled a massive cloud of charged particles out into space at millions of miles an hour.
Such eruptions — known as coronal mass ejections, or CMEs — can wreak havoc if they hit Earth squarely, temporarily disrupting GPS navigation, satellite communications and power grids. But this one isn't aimed directly at us, so there's no cause for alarm, experts say.
Space weather forecasters with the U.S. National Oceanic and Atmosperic Administration "estimate a 40 percent chance of polar geomagnetic storms when the cloud arrives," astronomer Tony Phillips wrote today on Spaceweather.com, a website that tracks skywatching and space weather events.
"High-latitude skywatchers should be alert for auroras tonight," Phillips added.The solar flare associated with Tuesday night's CME registered as an X-class flare, the most powerful type. It was the fourth X flare unleashed by a sunspot known as AR1748 since Sunday night (May 12).
While incredibly powerful, Tuesday's flare actually was the weakest of the four rapid-fire X flares, clocking in at X1.2. The previous three registered as X1.7, X2.8 and X3.2 flares, respectively. Those three all occurred while AR1748 was facing away from Earth, however, so they did not affect our planet.
AR1748 is currently rotating toward Earth and should be lined up with us more or less directly by Saturday (May 18), researchers say. And the sunspot is still busy, firing off two medium-strength M flares over the past two days.
Scientists classifly strong solar flares into three categories, with C being the weakest, M intermediate and X the most powerful.
X-class flares can cause long-lasting radiation storms in Earth's upper atmosphere and trigger radio blackouts. M flares can cause brief radio blackouts in the polar regions and occasional minor radiation storms, while C flares have few noticeable consequences. Strong solar flares can also supercharge Earth's auroras, creating dazzling northern lights displays.
The sun is currently in an active period of its 11-year solar weather cycle and is expected to reach peak activity later this year. The current cycle, known as Solar Cycle 24, began in 2008.
Scientists have been tracking sunspots, solar flares and other space weather events since they were first discovered in 1843. Today, an international fleet of spacecraft keeps constant watch on the sun's activity.
Hyperactive Sun Fires Off 3 Major Solar Flares in 1 Day
By Tariq Malik, SPACE.comMay 14, 2013
The sun, it seems, is in overdrive. Late Monday night, the sun unleashed its third major solar flare in 24 hours — the biggest and most powerful solar storm of the year, so far.
This latest sun storm erupted Monday (May 13) at 9:11 p.m. EDT (0111 GMT) and registered as an X3.2 solar flare, one of the strongest types of flares the sun can release, space weather officials said. It came on the heels of two other recent X-class solar flares on Sunday night and Monday, all of which were sparked by a highly active sunspot on the sun's far left side.
Officials at the NOAA Space Weather Prediction Center in Boulder, Colo., appeared amazed at the intense activity from the crackling sunspot. [Sun Unleashes Biggest Flares of 2013 (Photos)]
"Clearly an extraordinary active region is making its way fully onto the visible disk," SWPC officials wrote in a morning update today (May 14). "Can it keep up this hectic pace?"Two of the three recent solar flares have been associated with massive explosions, called coronal mass ejections, which flung super-hot solar material into space at millions of miles per hour. Because the sunspot firing off the flares is not yet facing Earth, the solar eruptions pose no threat to satellites and astronauts in orbit, NASA has said.
The Solar Dynamics Observatory captured amazing videos of the major solar flares and eruptions."This marks the 3rd X-class flare in 24 hours," officials with NASA's sun-watching Solar Dynamics Observatory wrote in a statement. "Just like the two before this one also happened over the eastern limb of the sun and is not Earth-directed."
According to astronomer Tony Phillips of Spaceweather.com, scientists have just given the active sunspot a name: AR1748. It is one of nine active numbered sunspots currently visible on the surface of the sun.
While AR1784 has been spouting off many solar flares in recent days,
most of them more moderate, M-class solar flares, the events on Sunday
and Monday are taking solar activity to another level.
"These are the strongest flares of the year so far, and they signal a significant increase in solar activity," Phillips wrote in a Spaceweather.com update this morning.
Scientists use a tiered space weather scale to classify solar flare
events, with each level representing a tenfold increase in power over
the one before. At the bottom of the scale are A and B type solar
flares, which have no effect on Earth. Next are C-class solar flares and
the stronger, yet still medium-strength, M-class solar flares, which
can supercharge Earth's auroras and cause radio blackouts when aimed at
Earth.
X-class solar flares are the most powerful types of solar storms. When aimed directly at Earth, these major solar events can pose a danger to astronauts and satellites in space, as well as interfere with radio and GPS navigation signals.
The X3.2 solar flare is the most powerful yet seen this year and the third-strongest sun storm of the current 11-year solar cycle, called Solar Cycle 24.
The second strongest was an X5.4 solar flare in 2012, while the largest event was an X6.9 flare in 2011. So far, there have been 18 X-class solar flares in Solar Cycle 24.
The first X-class solar flare of 2013 (the Sunday event) registered as an X1.7 on the flare scale, with the mid-day Monday flare rating as an X2.8, NASA officials said.
Solar activity on the sun rises and falls over the course of its 11-year cycle. The sun is active phase of Solar Cycle 24 as it approaches its peak activity period, called solar maximum, which is expected to occur later this year.
Scientists have been monitoring solar flares and other space weather events since their discovery in 1843. Today, NASA and other space agencies continuously monitor the sun with spacecraft like the Solar Dynamics Observatory to track potentially dangerous space weather events.
Sunspot Blasting Out Major Solar Flares Will Face Earth Soon
By Mike Wall, SPACE.comMay 14, 2013
The super-active sunspot responsible for unleashing the three most powerful solar flares of 2013 within a 24-hour stretch this week is slowly rotating toward Earth and will likely be facing our planet by the weekend, experts say.
Active Region 1748, as the sunspot is known, unleashed three monster solar flares between Sunday and Monday (May 12 to 13). Every one of the solar storms registered as an X-class flare — the most powerful type — with each successive event stronger than the last, culminating in an X3.2 megablast Monday night.
These solar explosions did not affect Earth, since AR1748 was not facing our planet at the time. But the sunspot is now circling into view, so future flares and any associated eruptions of super-hot solar plasma — called coronal mass ejections (CMEs) — could potentially target our planet, scientists say.
[Sun Unleashes Biggest Flares of 2013 (Photos)]
AR1748 should be near the center of the solar disk by around Saturday, Young added."In a couple of days, it will be far enough onto the disk that any CMEs that we got would probably have some impact on Earth," solar astrophysicist C. Alex Young, of NASA's Goddard Space Flight Center in Greenbelt, Md., told SPACE.com.
"If it sends something off, then we can expect to get some CMEs sort of head-on" at that point, he said.Sunspots are temporary dark and relatively cool patches on our star's surface where the local magnetic field is very strong. They frequently, but not always, serve as staging grounds for powerful solar flares and CMEs.
At about the size of two Earths, AR1748 is not a particularly large sunspot. (Sunspots can stretch for tens of thousands of miles across the solar surface.) But the active region does appear to have an unusually complex structure, Young said.
Because AR1748 is near the sun's limb at the moment, it's tough to say if its complexity is increasing, which could be an indicator of future activity. But things should become clearer in the next day or so, as scientists get a better look at the sunspot, he added.
While researchers will take AR1748's complexity and evolution into account when gauging its future eruption potential, they'll also look closely at its past behavior.
"One of the biggest indicators of an active region flaring is that it already flared," Young said. "In this case, the fact that it's already put out a really large flare gives it a strong possibility that it'll do it again."Scientists give AR1748 a 40 to 50 percent chance of firing off another X-class flare, he added, though this probability is a rough estimate that could change as further information becomes available.
X-class flares aimed at Earth can have consequences on a planet-wide scale, triggering widespread radio blackouts and long-lasting radiation storms.
Earth-directed CMEs have even more destructive potential. When a CME's charged particles interact with Earth's magnetic field, they can spawn geomagnetic storms powerful enough to disrupt GPS signals, radio communications and power grids.
Solar activity waxes and wanes over an 11-year cycle. The current cycle, called Solar Cycle 24, is ramping up toward an expected peak later this year.
Scientists have been tracking the sun's weather cycle since 1843, when it was first discovered. Today, NASA and other space agencies use sophisticated satellites and spacecraft to monitor the sun's activity with high-definition instruments to keep tabs on space weather events.
Earth's Rotating Inner Core Shifts Its Speed
LiveScience.comMay 13, 2013
Earth's solid-metal inner core is a key component of the planet, helping to give rise to the magnetic field that protects us from harmful space radiation, but its remoteness from the planet's surface means that there is much we don't know about what goes on down there. But some secrets of the inner core are being revealed by acoustic waves passing through the planet's heart and iron squeezed to enormous pressures in the lab. Two new studies, both detailed online May 12 in the journal Nature Geoscience, reveal that Earth’s inner core may actually be softer than previously thought, and that the speed at which it spins can fluctuate over time.
Under the liquid-metal outer layer of the Earth's core is a solid ball of superhot iron and nickel alloy about 760 miles (1,220 kilometers) in diameter. Scientists recently discovered the inner core is, at 10,800 degrees Fahrenheit (6,000 degrees Celsius), as hot as the surface of the sun.
Churning in the liquid outer core results in the dynamo that generates Earth's magnetic field. Geoscientists think interactions between the inner and outer cores may help explain the nature of the planet's dynamo, the details of which remain largely unknown.
"The Earth's inner core is the most remote part of our planet, and so there is a lot we don't know about it because we can't go down and collect samples," said Arianna Gleason, a geoscientist at Stanford University in California.Shifting speeds
One way scientists can learn more about the inner core is by analyzing acoustic waves from earthquakes that ripple through the inner core as they pass through the planet. Hrvoje Tkalcic, a geophysicist at the Australian National University in Canberra, and his colleagues relied on earthquake doublets — earthquakes that occur in pairs and generate extraordinarily similar acoustic waves — to investigate the inner core. Because these waves are so alike, the data they return are readily comparable, and because they are separated relatively briefly in time, they can help the researchers image subtle changes that might occur in that time frame.
Seismic observations and computer models of the Earth's innards suggested the inner core spins at a different rate than the mantle does, but there were conflicting estimates for how fast the inner core actually rotated. By analyzing 24 earthquake doublets, Tkalcic and his collaborators found the speed at which the inner core spun apparently fluctuated over the course of approximately decades between 1961 and 2007.
"It is the first observational evidence that the inner core rotates at a variety of speeds with respect to the mantle...It also reconciles old discrepancies," Tkalcic told OurAmazingPlanet. (Past analyses of how fast the inner core rotated came up with different speeds.)The inner core, on average, rotates eastward. At the speeds it travels, it might, on average, complete a revolution every 750 to 1,440 years. However, these speeds appear unstable, which makes it uncertain just how long it actually takes to finish a turn on its axis, Tkalcic said.
It remains unknown exactly why these fluctuations in speed happen. Gravitational and magnetic forces likely both play a part, Tkalcic said.
Weak iron
In another study, Gleason and her colleagues sought to learn more about the inner core by mimicking its conditions in the lab. They measured the strength of iron by squeezing it within a diamond anvil at room temperature while scanning it with X-rays.
"We know the Earth's inner core is composed mostly of iron, but we don't really know too much about the behavior of iron under the pressure and temperature at conditions in the core," Gleason said.The metal was subjected to more than 200 billion pascals of pressure, or about 180,000 times the pressure of the average human bite.
"We found the inherent mechanical strength of iron under those conditions is quite low, surprisingly weak," Gleason said.These findings may help explain why material within Earth's inner core is apparently distributed in a lopsided way, Gleason said. The weakness of iron might lead crystallites in the inner core to flow and line up a certain way, she explained.
Gleason noted that the researchers did not mimic the extreme temperatures found in the inner core, nor did the metal they experimented with match the composition of the inner core. In future experiments, they hope to use lasers to heat the metal to the proper temperatures, and test various iron-nickel alloys.
Solar Flares Explained: What You Need to Know
By Mike Wall, SPACE.comMay 13, 2013
The sun has unleashed two colossal flares since Sunday night, firing off its most powerful eruptions of 2013 in less than a day.
The first flare peaked Sunday (May 12) at 10:17 p.m. EDT (0217 GMT), registering as an X1.7-class eruption. The second flare, which occurred at midday on Monday (May 13), was even stronger, clocking in at X2.8, scientists said.
X-class flares are the most powerful type. Here's a brief rundown on solar flares, their classification and their potential impacts on Earth.
Classifying solar flares
Solar flares
occur when a buildup of magnetic energy on the sun is suddenly
released. They usually erupt from sunspots, temporary dark and
relatively cool patches on our star's surface where the local magnetic field is very strong.
Flares generate a burst of radiation across a wide range of the electromagnetic spectrum. They're often accompanied by coronal mass ejections (CMEs), which hurl enormous clouds of super-heated plasma into space.
Scientists classify strong solar flares into one of three categories: C, M or X (with A and B classes, too, for weaker eruptions). There's a tenfold increase in power from one class to the next, so an X flare is 10 times stronger than an M flare, and 100 times more powerful than a C.
There's also a finer gradation within each class, from 1 to 9 in the
case of C and M flares. But the number goes higher for X flares, because
it's the top of the scale and the sun occasionally fires off eruptions
more than 10 times stronger than an X-1. For example, in 2003, the sun
let loose a flare that registered as an X28 before overwhelming the
sensors that measured it. It remains the most powerful solar flare ever
recorded.
Effects on Earth
Flares that are C-class and weaker don't affect Earth in any meaningful way. M-class eruptions can generate brief radio blackouts at the poles and minor radiation storms that could endanger orbiting astronauts.
X-class flares, on the other hand, can have consequences on a planet-wide scale, triggering widespread radio blackouts and long-lasting radiation storms.
The CMEs that often accompany solar flares have even more destructive potential. When a CME's charged particles interact with Earth's magnetic field, they can spawn geomagnetic storms powerful enough to disrupt GPS signals, radio communications and power grids.
In March 1989, for example, a CME caused a power blackout in Quebec, leaving 5 million Canadians in the dark in cold weather for hours. The event caused about $2 billion in damages and lost business, scientists say.
We should expect more activity from the sun over the coming months.
Solar activity waxes and wanes on an 11-year cycle, and researchers
think the current cycle, known as Solar Cycle 24, will peak later this
year.
