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What Causes The Theta Aurora?
The theta aurora, named for ts resemblance to the eponymous Greek letter, is an oval-shaped region of electromagnetic activity at the edge of Earth and space. It cannot be seen from the ground, and its existence was undetermined until space-age observations let us view the Earth from an external vantage point, Unlike the regular auroras popularized on postcards and such, the cosmic mechanisms that birth theta aurora outbursts were poorly understood One possible explanation credits unusually hot globules of plasma crashing against our magnetosphere. Then combined satellite data fingered another culprit: funneled solar winds and magnetic mirrors (when ions bounce from high-density to low-density fields). It appears the theta aurora is caused by plasma confined within enclosed fields. The charged particles are heated and bounce against closed lines as if trapped Inside a giant, magnetic bouncy house. This explanation differs from the original supposition that the theta was caused directly by sweeping solar winds against our planet's magnetic mane.
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Why Was The Tohoku Earthquake Tsunami So Large?
The 9.0 magnitude Tohoku earthquake that devastated Japan in March 2011 was an absolute monster-the fifth-largest in recorded history. But the ensuing tsunami was uncharacteristically massive and impacted the island at an odd spot, scientifically speaking. The mystery persisted until NASA remembered it had two serendipitously aligned satellites that captured the tsunami in real-time. The chance of such a satellite being pointed in the right direction was one in 10 million. The ESA also had a set of eyes on the event. The data, oceanographic measurements accurate to the centimeter, revealed the devastation was caused by not one, but two tsunamis. The brutal earthquake launched two massive wave fronts at the island nation, and these two systems combined into what science has eloquently dubbed a "double tsunami." The catastrophe offered researchers their first definitive glimpse at this destructive phenomenon. Twin tsunamis had been implicated in previous disasters. For example, in 1960, a Chilean tsunami crossed large swaths of the Pacific Ocean to take 200 lives in Hawaii and Japan. But now that researchers have witnessed a bona fide merger, they'll be able to prediet future events, improve hazard maps, and devise better evacuation routes.
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. What Do The Tectonic Plates Slide On?
Seismic measurements are usually revealed by earthquakes. But Kiwi researchers didn't have time to wait for natural tremors, so they made their own. The team ventured to the southern tip of New Zealand's North Island and poured explosive slurry into a series of 50-meter-deep (160 ft), steel-insulated bore holes. The holes were drilled across a major subduction zone, where the Pacific plate joints the Australian plate. The explosion produced a downward- traveling earthquake and teased some telltale jiggles out ofthe crust. They found that the lithosphere (the crust) slides along a 5-kilometer-thick (3 mi) conveyor formed of a lubricating, jelly-like rock mixture. Officially the lithosphere asthenosphere boundary (LAB), this glorified Earth-lube disconnects the crust from the mantle and provides a cushy platform for continental shifts. It's believed the LAB's squishiness is a result of increased water or magma content. Surprisingly, a tiny increase of 1-2 percent compared to the crust is enough to form the gelatinous boundary.
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What's Causing The Global Warming Hiatus?
Global temperatures increased at high rates in the 20th century, but since 1998, there's been an unexpected lull. This has inspired optimism in the wasteful and righteousness in climate change deniers. To scientists, the decreased global warming rates are suspicious. It turns out that we're in the eye of the environmental tornado. The Pacific Ocean is doing us a huge favor by dissipating large chunks of solar radiation into its watery bosom, part of a natural cycle played out over tiny geological time frames. The global warming hiatus- now seen as more of a "false pause"- started in the late '90s. This date syncs with the back end of the El Nino warming event of 1997-1998, The Pacific Ocean cycles through its hot and cold phases for 16-20 years, suggesting a return to warmer waters any day now. Sadly, the intermittent periods of calm won't do much to buck long-term trends. But at least now we know happening,
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Do Wildfires Always Cause Global Warming?
It's only three months into the year, but we tnight have a winner for most ironic geopyrological discovery of 2015: Wildfires can cause regional cooling. This may seem wildly counter intuitive because fire is hot. And conventional wisdom tells us that fires transmute trees and related foliage into pollution, in the form of greenhouse gAsses like carbon dioxide. But the disintegration of large swaths of organic material can be beneficial as well. Clearing the shrubbery increases local albedo, or reflective value. The amount of sunlight bounced back out into space increases. This cooling is observed in boreal biomes. However, the immediate surge in burning pollution that accompanies a major fire does contribute to warming And as the black ash falls back to Earth, it blankets the region, increasing absorption of solar radiation. But after the ashes clear, it's smooth sailing First, a snowy and highly reflective surface is revealed to the Sun, and solar rays are reflected back into the cosmos. Then, new deciduous species replace the pre-fire conifers. And their young, gloSsy leaves offer additional reflective surfaces to thwart the Sun. In winter, the newcomers shed their leaves, unlike their piney predecessors, and a mirror-like terrain once again reveals itself. So yes, the initial fire is kind of an environmental hazard. But sclentists predict that in only eight decades, the effects reverse. At this point, the deleterious effects lire will have been undone, yet local cooling will perisist
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