Fire and the Future of Yellowstone

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 The high mountain forests of western North America need fire. Fire returns nutrients to the soil and replaces old stands and ground debris with young forest. Intense fires are a characteristic of the conifer forests, though they occur infrequently—once every 100 to 300 years.
The year 1988 brought one of those infrequent, severe fires to Yellowstone National Park. Drought and high temperatures combined to create extreme fire conditions. Fifty wildfires ignited, seven of which grew into major wildfires. By the end of the year, 793,000 acres had burned.
These images, taken by the Landsat satellites, contrast 1989 and 2011. Burned land is deep red in the 1989 image. By 2011, more than two decades later, the scar faded to tan-orange, but it was still present. Year-to-year images are available in the Earth Observatory’s World of Change article, Burn Recovery in Yellowstone.
Immediately after the fire, grass flourished in the ash-rich soil, followed by young trees. The slender saplings were still not dense enough to hide the burn scar. As these images indicate, it takes many decades for a conifer forest to recover to pre-fire conditions.
Western conifers burn when temperatures are high and plants and soil are dry. Such conditions will come together more frequently as the climate changes over the next century, and fires are already becoming more frequent. A 2011 study combined several climate models to estimate how fire could change in the Yellowstone ecosystem. Yellowstone is near a tipping point, the researchers assert, as warmer, dryer conditions will likely allow large fires to burn as frequently as every 30 years.
When fires occur infrequently, the forest has time to recover. More frequent fires, however, give the conifers little time to grow back. If this occurs, Yellowstone could lose its dense conifer forests and replace them with low montane woodland and grassland by 2050.

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Is That The 'Death Star' Suckling on the Sun?

What was that planet-sized 'Death Star'-like structure seen floating near the surface of the sun on Monday? Although sightings of supposed UFOs in space images are nothing new, this particular orb appears to be refueling with solar plasma -- there's even a hose extending from the sun's surface!
 Anyone familiar with solar images will immediately recognize the filament extending from the surface of the sun into the sun's atmosphere (or corona) -- it's a solar prominence.


Prominences are very well-known structures in the corona. Although their formation is still the subject of intense scientific scrutiny, we know that they are clouds of cool plasma encapsulated in long tubes of magnetism. But 'cool' is a relative term.
Typically, prominences have been measured to be of chromospheric temperatures. The chromosphere -- a 2,000-kilometer thick region of the lower solar atmosphere that is sandwiched between the solar "surface" (the photosphere) and the multi-million degree corona -- can reach temperatures of up to 24,000 Kelvin (or degrees Celsius), and prominences have a similar temperature characteristic.
So why are they so dark when viewed by solar observatories?
When solar telescopes like NASA's Solar Dynamics Observatory (SDO) observe the sun, they do so through filters. These filters are able to select a certain wavelength of electromagnetic radiation. Each wavelength corresponds to a certain temperature -- generally higher temperatures produce radiation of shorter wavelengths. Therefore, the most powerful, hottest, solar flares may generate X-ray radiation (hence "X-class" flares), whereas the "quiet sun" (areas of the cool photosphere with little magnetic activity) generate longer wavelength radiation that we can see with our own eyes -- a.k.a. visible light.

The tenuous gas in the sun's corona is very hot, so when the SDO studies the corona, it uses a filter that is able to "see" the multi-million degree plasma emitting radiation in a specific point of the extreme-ultraviolet (or EUV) part of the electromagnetic spectrum.
Therefore, should cooler plasma -- such as the plasma encased in a long prominence -- be observed inside the corona, it won't be emitting the same wavelength as the corona and will appear dark.
But what about the strange orb shape attached to the end of the prominence? That's actually a tunnel, or "coronal cavity," carved into the corona by the magnetic structure atop the prominence.
"When you look at it from the edge of the sun, what you actually see is a spherical object. You're actually looking down the tunnel. And this tunnel sits up top of the filament," NASA solar physicst C. Alex Young explained on his website The Sun Today.
  As we view the sun with more sophisticated space telescopes, our eyes are being opened to the incredible dynamics that connect the sun's interior to its atmosphere. And as this video shows, erupting coronal cavities can trigger the formation of CMEs. CMEs are the target for much scrutiny by space weather experts as they can have a dramatic impact on modern technology in space and on Earth, so understanding these features is paramount to predicting the sun's temper tantrums.

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Meteorite Punches Hole Through Oslo Shed

A Norwegian family was flabbergasted to find that what appeared to be a piece of a meteorite had crashed through the roof of their allotment garden hut in the middle of Oslo, media reported Monday.

The rock weighing 585 grams (1lb 4oz), which split in two, probably detached from a meteorite observed over Norway on March 1, experts said, and had landed on the empty hut in the Thomassen family's allotment in a working-class neighbourhood of the Norwegian capital.

Astrophysicist Knut Joergen Roed Oedegaard and his wife Anne Mette Sannes, a meteorite enthusiast, identified the object as a breccia, or a rock composed of broken fragments of minerals or rock.
"It is a sensation in more than one way. On one hand because it is rare that a piece of meteorite goes through a roof and on the other hand because it is a breccia, which is even harder to find," Sannes told AFP.
 She said the owners of the meteorite pieces wanted to keep them in Norway, maybe in a museum.

Meteorites speed through space and generally break up as they enter our atmosphere, but it is extremely rare for the debris to fall on inhabited areas, according to Serge Koutchmy, a researcher at the Paris Astrophysical Institute.

"This family is very lucky," Koutchmy told AFP.
"First off because the piece of meteorite did not cause much damage, but also because it is worth a small fortune," he said.
A meteorite from Mars, for instance, can fetch around 5,000 kroner ($876) per gram (0.002 pounds), according to geophysicist Hans Amundsen quoted on the website of the Verdens Gang daily, adding though that it remained unclear where the meteorite pieces that landed in Oslo came from and how rare they were.

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Nuking Asteroids: It's a Megaton Of Fun!

Asteroids: they're big, scary and can kill millions. Nuclear weapons: they're big, scary and can kill millions. Wouldn't it make sense to unite the two? Seems like a perfect match.
We've gone full circle more than once in the discussion about asteroid collision mitigation plans in recent years. The once sci-fi space rock disposal solution is becoming more sci-fact every time the ugly subject of errant space rocks is discussed. It's a "given" that if an incoming asteroid were to be spotted last-minute, we'd obviously need to launch our entire nuclear deterrent into space.

Unfortunately, there's a catch (actually, there's a few catches) with this plan:
1) What if we shot a nuke at an incoming asteroid and it was woefully weak compared to the structure of the asteroid? All we'd succeed in doing is turn the deadly asteroid into a radioactive deadly asteroid.
2) What if we shot a nuke at an incoming asteroid, the asteroid blew up, but there's enough time for the asteroid to reform under the mutual gravity of its debris? Well, that's not good either.
3) What if we shot a nuke at an incoming asteroid, the asteroid blew up, but now we have a thousand smaller chunks of the deadly asteroid racing toward us? Well, it would be like choosing between getting shot by a cosmic bullet, or cosmic buckshot. The former packs a bigger punch, while the latter blanket-bombs an entire hemisphere.
With all these "what if's" we'd be stupid to launch a nuclear weapon at an asteroid, right?

Well, despite the flaws, it turns out that going nuclear is probably still the 'best' option if we spotted an "on-target Apophis" tomorrow, and a group of scientists have been busy simulating this event.
In a January video from Los Alamos National Laboratory, New Mexico, scientists using the awesome power of 32,000 processors inside the Cielo supercomputer have simulated the impact of a 1-megaton nuclear explosion on the surface of a 500-meter wide asteroid.
Their conclusion is fabulous: Yes, a big boom can solve a big problem.
"Ultimately this 1-megaton blast will disrupt all of the rocks in the rockpile of this asteroid, and if this were an Earth-crossing asteroid, would fully mitigate the hazard represented by the initial asteroid itself," said Los Alamos scientist Bob Weaver.
Basically, by detonating this nuclear warhead on the surface of an asteroid like the one visited by the Japanese Hayabusa asteroid sample return mission, a shock wave will propagate through the "rubble pile" (the nickname given to asteroids composed of loose material clumped together via a weak gravitational field), disrupting the asteroid enough so it can be pushed out of the way or ripped apart. It may not solve the problem of getting hit by lots of smaller pieces of asteroid, but if there's enough time, this debris may be pushed out of harm's way by the blast. Humans: 1, Asteroid: zero.

Most recently, the discovery of asteroid 2012 DA14 has prompted some concern that the next asteroid to hit Earth probably won't be of extinction-level proportions, but more of city- or country-sized proportions. The 150-meter wide DA14 definitely wont hit us in 2013, but it will pass under the orbit of geosynchronous satellites, a fact that seems a little too close for comfort.
And by only having a one-year warning, what could possibly be done to mitigate the impact risk if DA14 was on target?
It seems there are only two options. We either nuke it, as the Los Alamos research suggests, or let it hit us. (And yes, the latter is a viable option).

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Solar Storm Paints Stunning Northern Lights: Big Pic

March 9, 2012 -- Coronal mass ejections unleashed by Tuesday night's powerful X-class solar flares collided with Earth's magnetosphere yesterday morning, eventually sparking amazing displays of aurorae around the world.

PHOTOS: What is the Aurora Borealis?

This stunning photo comes courtesy of Jónína Óskarsdóttir in Faskrudsfjordur, Iceland, and shows the energy of the upper atmospheric activity.

"No words can describe the experience of the Northern Lights show tonight," said Óskarsdóttir on SpaceWeather.com. "This is just a 1s exposure!"

Although the initial impact of the CME was weaker than expected, the magnetic orientations have since aligned such as to deposit more energy into Earth's magnetosphere, intensifying the storm activity -- and the potential for more aurorae!

-- by Jason Major.

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Solar Storm Warning Satellite on Last Legs

Every time a giant solar storm -- like the one that blasted by Earth earlier this week -- rushes past NASA's Advanced Composition Explorer satellite, scientists at NOAA's space weather forecasting branch cringe.
The satellite, nicknamed ACE, provides the only advance notice of incoming high-energy particles from the sun which can wreak havoc on radio, GPS, satellite communications that are now embedded in modern life.
   
Launched in 1997, ACE gives forecasters advance notice if a storm is headed toward Earth. Its measurements of solar wind strength, magnetic fields and speed were key to forecasters' assessments Thursday that Earth would be spared a direct hit from a geomagnetic storm that left the sun on Tuesday.
But how much longer ACE will last is anyone's guess.

"It would be a very bad day for us if that spacecraft was not working," William Murtagh, program coordinator for NOAA's Space Weather Prediction Center in Boulder, Colo., told Discovery News.
    "When an eruption occurs on the sun, there are still quite a few question marks as to if it's going to hit the Earth and when it's going to hit the Earth," Murtagh said.
Until the sun's free-flying and highly energetic outbursts, known as coronal mass ejections, hit the ACE spacecraft, forecasters don't know the orientation of their embedded magnetic fields. Depending on the polarity, or alignment, Earth's magnetic shield will either peel away, giving the highly charged particles more freedom to disturb electrically sensitive equipment and communications, or rebuff the particles, such as what happened during this week's outburst.

Stationed about 1 million miles from Earth, ACE provides early warning of what's headed toward Earth. NOAA says more than 22,000 utility operators, airlines, satellite owners, GPS users and others are signed up to receive space weather alerts and millions more get the information on NOAA's website.
"ACE is a single point of failure and it's old," Murtagh said. "Every time I have a space weather storm I cringe a little bit that our very own space weather satellite doesn't succumb to the storms I'm relying on it to help forecast."
Another satellite with space weather sensors was slated to be launched in 2003 by the ill-fated shuttle Columbia crew, but the spacecraft, known as Triana, was nixed by the Bush administration because of its backing by former vice president and Democratic presidential nominee Al Gore. (Informally, Triana was sometimes referred to as GoreSat.)
Gore championed the spacecraft for its ability to continuously relay live pictures of Earth from the vantage point of 1 million miles away in space, in hopes that the global view of the blue planet would rally environmental awareness.
"There were no technical reasons why it couldn't go. We were getting ready to send it the Cape (Kennedy Space Center) for launch and we got an order that the mission was not going to go," project scientist Adam Szabo, with NASA's Heliospheric Physics Laboratory at the Goddard Space Flight Center in Maryland, told Discovery News.
After its ride was canceled, Triana was put into storage at Goddard. It is now undergoing checkouts and refurbishments in preparation for rebirth as NOAA-operated space weather sentry. The U.S. Air Force is picking up launch costs and expects to issue a solicitation soon to get the satellite, now renamed the Deep Space Climate Observatory, or DSCOVR, a ride to space.
The camera championed by Gore is still part of the spacecraft, along with a trio of instruments to monitor space weather and sensors to measure reflected heat from Earth.
Launch is targeted for June 2014. The sun's 11-year solar cycle is expected to peak in May 2013. Heightened solar activity, which is ramping up this year, will continue for about the next six years.

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