Seven Wonders of the Sun and Other Stars

Seven Wonders of the Sun and Other Stars — page 5 — The collision set off a big magnetic storm a disturbance of the magnetic ﬁeld This kind of storm can hurt electrical power systems For instance in 1989 a magnetic storm damaged power lines in Quebec Canada People in some parts of Quebec had no electricity for nine hours Magnetic storms can cause other problems too They can damage or disrupt radio communications Global Positioning Systems GPS and cell phone service BRACING FOR TROUBLE Astronomers watched closely as the huge solar ﬂare exploded in October 2003 They tracked the ﬂare so they could warn people about it For instance they told workers at power companies to prepare their equipment for a magnetic storm With advance warning power companies could take action to keep the electricity from going out Seven Wonders of the Sun and Other Stars Luckily the magnetic storm was not as bad as astronomers had feared The charged particles that caused the storm did not hit Earth’s magnetic ﬁeld directly They hit at an angle causing less damage The storm weakened quickly Its blast of energy soon died away It caused only minor damage to communications systems But the magnetic storm also had a positive effect It created spectacular auroras Auroras are 8 AWESOME Auroras Auroras are swirling curtains of colorful lights in the night sky They are usually green but can also be red purple blue or white Auroras occur when the solar wind carries electrically charged particles from the Sun to Earth’s magnetic ﬁeld When the particles enter this ﬁeld they move toward the north and south poles As they move the particles rub against gases in Earth’s atmosphere The electrical charges in the particles cause the atmosphere to glow Some auroras cover thousands of miles Normally auroras appear only near the north and south poles That’s why auroras are also called northern lights and southern lights When a solar ﬂare causes a big magnetic storm many more particles than normal enter Earth’s magnetic ﬁeld Then people in many other places can see these beautiful colored lights

Seven Wonders of the Sun and Other Stars — page 6 — An aurora makes a spectacular display in the sky over Portage Lake in the Chugach Mountains of Alaska Auroras are common near the north and south poles at the top and bottom of Earth’s magnetic ﬁeld An aurora happens when particles from the Sun hit the magnetic ﬁeld and cause the atmosphere to glow bands of glowing colored lights in the sky People in many parts of the world saw swirling curtains of light when the magnetic storm hit The beauty of the shimmering dancing lights was awe inspiring When I was eight years old I watched auroras swirling in the winter skies of Minnesota They looked like glowing curtains of colored light I was lucky to see them so far from the North Pole Later on I learned that the auroras I saw were caused by a big solar ﬂare exploding from the Sun Lee Hansen science writer 2008 Solar Storms 9

Seven Wonders of the Sun and Other Stars — page 7 — The Extreme Ultraviolet Imaging Telescope took this picture of the Sun The telescope is on board the Solar and Heliospheric Observatory SOHO a spacecraft that orbits the Sun OUR AMAZING SUN The Sun measures about 860,000 miles 1,384,000 kilometers across That’s one hundred times wider than Earth If the Sun were hollow more than one million planets the size of Earth would ﬁt inside it The Sun is extremely heavy too It is about six hundred times heavier than all the planets in our solar system put together Like most other stars the Sun is a huge ball of hot burning gases The surface of the Sun burns at about 10,000 F 5,537 C The core or center of the Sun is even hotter The core burns at about 27 million F 15 million C 10

Seven Wonders of the Sun and Other Stars — page 8 — The Sun is vital to life because its light makes plants grow When you eat a plant a carrot a banana a slice of bread you are eating the product of sunlight Ken Croswell U S astronomer 2007 The Sun’s core is like a giant furnace Inside this furnace hydrogen turns into helium This change is called a nuclear reaction Nuclear reactions release huge amounts of energy The energy boils up from the core all the way to the Sun’s surface Like Earth the Sun has an atmosphere a layer of gases surrounding its surface The outermost layer of the Sun’s atmosphere is called the corona which means crown The corona looks a little like a halo or crown of light around the Sun From the corona the energy created in the Sun’s core ﬂows into space The Sun releases this energy in two main ways First the Sun sends out waves of radiation These waves include the sunlight we can see and the warm rays of heat we can feel Second the Sun sends out tiny electrically charged particles The constant stream of radiation and particles from the Sun is called the solar wind This wind from the Sun is very different from any wind on Earth As the solar wind ﬂows out toward Earth and far beyond it carries the light heat and other energy of the Sun The Sun’s light and heat are vitally important to our planet Without sunlight there would be no life on Earth Green plants could not grow Animals and people would have nothing to eat And Earth itself would be a frozen lifeless world SUNSPOTS Like Earth the Sun rotates or spins around The areas near the equator the widest part of the Sun spin faster than its north and south poles Also like Earth the Sun has a magnetic ﬁeld The magnetic ﬁeld is made up of invisible ﬁeld lines They run between the Sun’s north and south poles At the equator where the Sun rotates fastest these lines get stretched out This stretching tangles up the magnetic ﬁeld lines like an old garden hose or a twisted computer cord Solar Storms 11

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