Physical Science 8th grade (1).pdf

Weather on our planet is affected by factors such as

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Weather on our planet is affected by factors such as temperature, wind, precipitation, and by the sun’s heat and light. In space, the sun drives the weather. Explosions on the sun’s surface can cause radiation storms, changes in magnetic fields, and movement of energetic particles. The fast-moving solar wind carries charged particles away from the sun. Some of these particles and energy are able to penetrate Earth’s upper atmosphere, and when this happens, an aurora is created - a spectacular show of lights. Charged particles and auroras Our planet is a magnetic object. Magnetic field lines travel between the north and south poles. Charged electron particles trapped in these field lines create what is known as Earth’s magnetic field (also called the magnetosphere). This magnetosphere protects Earth from solar wind that contains energetic particles and radiation. An aurora is caused by energy from the sun. Charged particles from the sun travel down Earth’s magnetic field lines forming oval shapes. These so-called auroral ovals cover each magnetic pole. When electrons hit Earth’s upper atmosphere, light particles are released. These colliding solar particles and atmospheric gases create aurora lights. Generally, aurorae occur at higher latitudes, closer to the magnetic poles. Auroral ovals are usually located at 60° and 70° latitude, north and south. At 45°, aurorae are seen about fives times per year. Above 55°, aurorae are visible almost every night if viewing conditions are right. In November 2004, auroral ovals could be seen as far south as Arizona, whose latitude is 31° to 37°. Dazzling details An aurora looks like streaks of colored light in the dark night sky. Commonly seen aurora colors include green, yellow, and red. The gases present in the atmosphere determine the color. The electromagnetic radiation in an aurora also includes infrared and ultraviolet, neither of which the human eye can see. The aurora in the Northern Hemisphere is called aurora borealis or the northern lights, and is popularly viewed from Alaska, Canada, Iceland, Scandinavia, and Russia. In the Southern Hemisphere, the southern lights, or aurora australis, tend to occur in remote, barely populated areas. Solar wind Chapter 17 Connection
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365 U NIT 6 A STRONOMY This photo of aurora australis was taken at the Antarctica South Pole Weather Station in 1979. Clear, dark nights are best for seeing an aurora. Cloud cover, moonlight, and city lights can interfere with viewing. Space Environment Center The National Oceanic & Atmospheric Administration (NOAA) and the Air Force operate the Space Environment Center (SEC) in Boulder, Colo. The center provides real-time information about solar events and space weather that may affect people and equipment. It issues alerts and warnings to any organization that needs space weather information.
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