Megastorms.Last fall, the sun unleashed a series of powerful storms. The fiercest of the bunch turned out to be one of the strongest solar flares (eruptions of energy from the sun) ever recorded. And even though the sun is about 150 million kilometers (93 million miles) away, these flares spelled danger for Earth. Why did our gaseous gas·e·ous adj. 1. Of, relating to, or existing as a gas. 2. Full of or containing gas; gassy. star turn so ferocious? Scientists blame a group of sunspots sunspots, dark, usually irregularly shaped spots on the sun's surface that are actually solar magnetic storms. The Chinese recorded dark features on the sun seen with the naked eye in 28 B.C. (cooler areas of the sun that have intense magnetism). When a sunspot sunspot Cooler-than-average region of gas on the Sun's surface associated with strong local magnetic activity. Sunspots appear as dark spots, but only in contrast with the surrounding photosphere, which is several thousand degrees hotter. flares, a cloud of radiation (a form of high-energy waves or particles) erupts into space. That's not all. Energized particles, called protons and electrons, carrying some of the sun's magnetism also explode. "The recent eruptions headed straight for us, like a freight train traveling about 5 million miles per hour," says John Kohl, a solar physicist at the Harvard-Smithsonian Center for Astrophysics The Harvard-Smithsonian Center for Astrophysics (CfA) is located in Cambridge, Massachusetts. It consists of the Harvard College Observatory and the Smithsonian Astrophysical Observatory. The Center is located at 60 Garden Street. . "The radiation produced effects similar to those resulting from chest X-rays," explains Kohl. Too much radiation can kill or damage cells. "Without the full protection of Earth's atmosphere “Air” redirects here. For other uses, see Air (disambiguation). Earth's atmosphere is a layer of gases surrounding the planet Earth and retained by the Earth's gravity. It contains roughly (by molar content/volume) 78% nitrogen, 20.95% oxygen, 0.93% argon, 0. (a protective layer of gases), astronauts and airplane pilots had to take special precautions," adds Kohl. Astronauts holed up in a protected section of the International Space Station. And some pilots flew lower than usual so Earth's atmosphere could shield passengers from the incoming radiation. The solar storms weren't all bad, though. The flurry of high-energy particles and magnetism triggered auroras (colored lights in the sky, usually seen near Earth's poles) for sky watchers as far south as Texas (see diagram, right). HOW DO AURORAS FORM? 1 Solar wind solar wind, stream of ionized hydrogen—protons and electrons—with an 8% component of helium ions and trace amounts of heavier ions that radiates outward from the sun at high speeds. (a stream of charged particles and magnetism) blows from the sun toward Earth. 2 Earth's magnetic field Earth's magnetic field (and the surface magnetic field) is approximately a magnetic dipole, with one pole near the north pole (see Magnetic North Pole) and the other near the geographic south pole (see Magnetic South Pole). usually deflects most of the charged particles. It traps the rest. 3 Charged particles and magnetism carried from the sun collide with Earth's magnetism. This causes electrons to speed down Earth's magnetic field lines toward the poles. 4 There, the night sky lights up with auroras when electrons strike oxygen and nitrogen gas in Earth's upper atmosphere. [ILLUSTRATION OMITTED] NIGHT LIGHTS: Auroras may appear to be low in the sky, but they actually occur more than 60 kilometers (40 miles) overhead. FIRED UP: When a solar flare (bright spot, below) erupts on the sun, it can take days for the charged particles to reach Earth. |
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