Showing posts with label solar. Show all posts
Showing posts with label solar. Show all posts

Thursday, March 08, 2012

Strong solar storm heading for Earth

Strong solar storm heading for Earth
Largest solar flares of this solar cycle in this NASA photo taken on March 6, 2012
(Reuters) - A strong geomagnetic storm is racing from the Sun toward Earth, and its expected arrival on Thursday could affect power grids, airplane routes and space-based satellite navigation systems, U.S. space weather experts said.

The storm, a big cloud of charged particles flung from the Sun at about 4.5 million miles per hour (7.2 million km per hour), was spawned by a pair of solar flares, scientists said.

This is probably the strongest such event in nearly six years, and is likely more intense than a similar storm in late January, said Joseph Kunches, a space weather specialist at the U.S. National Oceanic and Atmospheric Administration (NOAA).

This solar disturbance is a three-stage affair, or as Kunches said in a telephone interview from Boulder, Colorado: "We hit the trifecta."

These are the stages he described, with the first two already affecting Earth:

* First, two solar flares moving at nearly the speed of light reached Earth late on Tuesday. Such flares can cause radio blackouts.

* Then, solar radiation hit Earth's magnetic field on Wednesday, with possible impact on air traffic, especially near the poles, satellites and any astronauts taking space walks. This phase could last for days.

* Finally, the plasma cloud sent by the coronal mass ejection, which is basically a big chunk of the Sun's atmosphere, is expected to arrive at Earth early on Thursday.

This phase can disrupt power grids, satellites, oil pipelines and high-accuracy GPS systems used by oil drillers, surveyors and some agricultural operations, scientists said.

GPS systems used for less-refined functions, such as the turn-by-turn navigation found in many cars, should not be affected, according to NOAA's Doug Biesiecker.

Kunches said the geomagnetic component of the storm may arrive a bit ahead of schedule because it follows a previous storm that left the Sun on Sunday and is currently buffeting the Earth's magnetosphere.

"When you've already had one coronal mass ejection storm, sometimes the next coronal mass ejection storm is faster to get here," Kunches said.

These storms could produce some vivid auroras, according to experts. In the Northern Hemisphere, the aurora borealis could be visible at mid-latitudes, which in the United States could include New York, Illinois and Iowa.

Such stormy space weather is unusual in recent history, according to Harlan Spence, an astrophysicist at the University of New Hampshire who is principal investigator on the Cosmic Ray Telescope for the Effects of Radiation (CRaTER) aboard NASA's Lunar Reconnaissance Orbiter.

"These relatively large (solar) events, which we've had maybe a couple of handfuls total in the course of a decade, we've now had two or three of them, more or less right on top of each other," Spence said by telephone.

The Sun is on the ascendant phase of its 11-year cycle of solar activity, with the peak expected next year, scientists said.

"It's a clear harbinger that the Sun is waking up," Spence said. "We're trying to put this in context not only ... of what has the Sun done in the past, but what is the biggest thing the Sun is capable of and what should we be planning for in terms of extreme sorts of events in the future."

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Tuesday, January 24, 2012

Solar Storm Now Hitting Earth, Called Strongest Since 2005, Could Affect Astronauts

Solar Storm, Nasa
A View of Solar Storm on the surface of blazing Sun
WASHINGTON -- The sun is bombarding Earth with radiation from the biggest solar storm in more than six years with more to come from the fast-moving eruption.

The solar flare occurred at about 11 p.m. EST Sunday and will hit Earth with three different effects at three different times. The biggest issue is radiation, according to the National Oceanic and Atmospheric Administration's Space Weather Prediction Center in Colorado.

The radiation is mostly a concern for satellite disruptions and astronauts in space. It can cause communication problems for polar-traveling airplanes, said space weather center physicist Doug Biesecker.

Radiation from Sunday's flare arrived at Earth an hour later and will likely continue through Wednesday. Levels are considered strong but other storms have been more severe. There are two higher levels of radiation on NOAA's storm scale – severe and extreme – Biesecker said. Still, this storm is the strongest for radiation since May 2005.

The radiation – in the form of protons – came flying out of the sun at 93 million miles per hour.

"The whole volume of space between here and Jupiter is just filled with protons and you just don't get rid of them like that," Biesecker said. That's why the effects will stick around for a couple days.

NASA's flight surgeons and solar experts examined the solar flare's expected effects and decided that the six astronauts on the International Space Station do not have to do anything to protect themselves from the radiation, spokesman Rob Navias said.

A solar eruption is followed by a one-two-three punch, said Antti Pulkkinen, a physicist at NASA's Goddard Space Flight Center in Maryland and Catholic University.

First comes electromagnetic radiation, followed by radiation in the form of protons.

Then, finally the coronal mass ejection – that's the plasma from the sun itself – hits. Usually that travels at about 1 or 2 million miles per hour, but this storm is particularly speedy and is shooting out at 4 million miles per hour, Biesecker said.

It's the plasma that causes much of the noticeable problems on Earth, such as electrical grid outages. In 1989, a solar storm caused a massive blackout in Quebec. It can also pull the northern lights further south.

But this coronal mass ejection seems likely to be only moderate, with a chance for becoming strong, Biesecker said. The worst of the storm is likely to go north of Earth.

And unlike last October, when a freak solar storm caused auroras to be seen as far south as Alabama, the northern lights aren't likely to dip too far south this time, Biesecker said. Parts of New England, upstate New York, northern Michigan, Montana and the Pacific Northwest could see an aurora but not until Tuesday evening, he said.

News by Huffingtonpost

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Saturday, December 17, 2011

Comet defies death, brushes up to sun and lives

Comet to Sun
WASHINGTON (AP) — A small comet survived what astronomers figured would be a sure death when it danced uncomfortably close to the broiling sun.

Comet Lovejoy, which was only discovered a couple of weeks ago, was supposed to melt Thursday night when it came close to where temperatures hit several million degrees. Astronomers had tracked 2,000 other sun-grazing comets make the same suicidal trip. None had ever survived.

But astronomers watching live with NASA telescopes first saw the sun's corona wiggle as Lovejoy went close to the sun. They were then shocked when a bright spot emerged on the sun's other side. Lovejoy lived.

"I was delighted when I saw it go into the sun and I was astounded when I saw something re-emerge," said U.S. Navy solar researcher Karl Battams.

Lovejoy didn't exactly come out of its hellish adventure unscathed. Only 10 percent of the comet — which was probably millions of tons — survived the encounter, said W. Dean Pesnell, project scientist for NASA's Solar Dynamics Observatory, which tracked Lovejoy's death-defying plunge.

And the comet lost something pretty important: its tail.

"It looks like the tail broke off and is stuck" in the sun's magnetic field, Pesnell said.

Comets circle the sun and sometimes get too close. Lovejoy came within 75,000 miles of the sun's surface, Battams said. For a small object often described as a dirty snowball comprised of ice and dust, that brush with the sun should have been fatal.

Astronomers say it probably didn't melt completely because the comet was larger than they thought.

The frozen comet was evaporating as it made the trip toward the sun, "just like you're sweating on a hot day," Pesnell said.

"It's like an ice cube going by a barbecue grill," he said.

Pesnell said the comet, although only discovered at the end of November by an Australian observer, probably is related to a comet that came by Earth on the way to the sun in 1106.

As Comet Lovejoy makes its big circle through the solar system, it will be another 800 or 900 years before it nears the sun again, astronomers say.

News by Yahoo

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Monday, December 12, 2011

Solar Storms Are "Sandblasting" the Moon, NASA Study Hints

solar storm
Solar Storm
The moon gets periodically "sandblasted" by intense solar storms that can strip tons of material from the lunar surface, a new NASA study suggests.

The sun is constantly emitting charged particles, or ions, in all directions in a stream called the solar wind. Scientists previously knew that solar ions can collide with and eject material on the moon's surface in a process dubbed sputtering.

But a new computer simulation finds that this sandblasting effect kicks into high gear during intense bursts of solar plasma—charged gas—known as coronal mass ejections (CMEs).

A strong CME can hurl about a billion tons of solar particles at up to a million miles (1.6 million kilometers) an hour in a cloud that is many times the size of Earth.

Normal solar wind is made up mostly of lightweight protons—hydrogen atoms that have been stripped of their electrons. But CMEs contain a much higher percentage of heavier ions such as helium, oxygen, and even iron.

These heavier atoms slam into the moon with greater force than protons, so they can dislodge a larger number of atoms from the surface.

"We found that when this massive cloud of plasma strikes the moon, it acts like a sandblaster and easily removes volatile material from the surface," study co-author William Farrell, leader of the Dynamic Response of the Environment At the Moon, or DREAM, team at NASA's Goddard Space Flight Center in Greenbelt, Maryland, said in a statement.

"The model predicts 100 to 200 tons of lunar material—the equivalent of ten dump truck loads—could be stripped off the lunar surface during the typical two-day passage of a large CME."

Once ejected, about 90 percent of sputtered moon particles escape into space, where they become ionized and are drawn into the solar wind, said study co-author Rosemary Killen, also of NASA Goddard.

"The material is in atomic form," Killen added in an email to National Geographic News. "It is not meteoric and does not produce meteor showers" on Earth.

Sputtering Can Help Probe Moon's Chemistry?

CMEs are most likely to happen during solar maximum, a period of high magnetic activity on the sun that occurs about once every 11 years.

"The more active the sun, the more often coronal mass ejections take place," said Richard Elphic, a planetary scientist at the NASA Ames Research Center in California who was not involved in the study.

"You can have at the height of solar maximum a [large] CME maybe every week or so, and in some cases every few days. And that might be followed by a couple weeks of quiet."

Right now the sun is ramping up toward the next predicted solar maximum in 2013—which might aid research that uses sputtering to reveal clues about lunar chemistry.

A new moon orbiter scheduled to launch in 2013, called the Lunar Atmosphere And Dust Environment Explorer, or LADEE, could test the new model's predictions.

If the simulation is correct, then CME sputtering should loft lunar surface atoms to LADEE's orbital altitude, around 12 to 30 miles (20 to 50 kilometers).

"As the LADEE project scientist," Elphic said, "my excitement is in using these CME 'scavenging events' as active probes of the sputtering process, to learn what [types of atoms] are liberated and how long they stick around before equilibrium returns."

Moon Landing Footprints in No Danger

While the new model hints that the amount of lunar material stripped off by sputtering is more than scientists had thought, the amount of lost material is still very small compared to the total mass of the moon.

Also, the loss of lunar surface material is more or less balanced by incoming particles from micrometeorites, meteors, and the solar wind itself.

That means Earth's only natural satellite—and the features on it—are in no danger of being eroded away anytime soon. (Also see "The Moon Has Shrunk, and May Still Be Contracting.")

"The astronaut's footprints will still be there in recognizable form after a million years—if we're still around to see them," Elphic said.

News by Nationalgeographic

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