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'''Konvektiovyöhyke''': Tällä alueella kuumat kaasut siirtyvät pintaa kohden ja kylmät painuvat alemmaksi.
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== Auringonpilkut ==
[[Kuva:Sun projection with spotting-scope large.jpg|thumb|200px|Tummat alueet ovat auringonpilkkuja]]
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Auringonpilkut ovat tummempia kohtia Auringon pintakerroksessa. Vaikka auringonpilkku onkin tumma verrattuna muuhun Aurinkoon, on se valtavan kirkas. Auringonpilkut ovat ympäristöään viileämpiä, "vain" 4000 °C. Auringonpilkut johtuvat Auringon magneettikentän muutoksista. Niiden määrä vaihtelee noin 11 vuoden jaksoissa.
==What are sunspots?==
[[Image:Sunspot.gif|thumb|200px|The dark areas are sunspots]]
Sunspots are dark spots on the Sun, but they are still brighter than lightning. Sunspots look darker than the rest of the Sun because they are a little cooler. Even though sunspots are cooler than the rest of the Sun, they are still hot — about 4000 °C (7000 °F). Sunspots are caused by changes in the Sun’s magnetic field. The magnetic field stops convection, which causes the sunspot areas to cool off and become darker. Sunspots usually form in groups which are carried around the Sun as it rotates.
The number of sunspots we see goes up and down every 11 years.
== Flaret ja protuberanssit ==
==What is the Solar Atmosphere like?==
Auringosta purkautuu välillä valtavia roihuja, jotka voivat olla jopa kymmeniä tuhansia kilometrejä pitkiä. Näitä roihuja kutsutaan ''proturberansseiksi''. Jos roihu lentää niin pitkälle, että se irtoaa Auringosta, sitä kutsutaan ''flareksi''
Above the photosphere, the Sun’s gases are not very dense at all. There are two layers that we can see with special telescopes. Above that, gases stream out as ''solar wind'' that reaches to the edge of the Solar System.
[[en:Image:Sunspot_TRACE.jpeg|left|200px|thumb|A closeup view of a sunspot and prominences]]
== Aurinkotuuli ==
=== Prominences and solar flares ===
[[Kuva:Auroraborealissm.jpg|thumb|Revontulia]]
Auringon pintakerroksista purkautuu atomien osia valtavalla nopeudella koko ajan. Tämä aurinkotuuleksi nimetty ilmiö aiheuttaa muun muassa revontulia. Tulevaisuudessa aurinkotuulta voidaan ehkä käyttää avaruusalusten voimanlähteenä.
If you have a telescope with special filters, you can see bumps around the edge of the Sun. Each one of these is called a ''prominence''. They look like volcanoes erupting. They are hundreds or thousands of kilometers long. Some are bigger than the Earth. They often seem to come from sunspots. Sometimes they get so far away from the Sun that they fly away from it. Then they are called ''solar flares''.
=== Chromosphere ===
''Chromosphere'' means "color ball". It is just above the photosphere. It is not as bright as the photosphere, and you can’t normally see it. But you can see it just before a solar eclipse (only with special filters!). It looks like a flash of all the colors of light. Surprisingly, the Chromosphere is even hotter than the photosphere, at some parts over 20,000 °C.
=== Corona ===
[[Image:Solar_eclips_1999_4.jpg|250px|thumb|right|The Sun's corona during an eclipse]]
''Corona'' means crown. That is what pictures of the corona look like. It is just above the chromosphere. It is hotter than the photosphere, and it glows. It is made of thin gases, and blows away as solar wind. It shifts and changes, but it is hard to see, even with special telescopes.
=== Solar wind ===
At the top of the corona, some of the gas blows out as solar wind. It blows fast — about 60 km per second (more than 100,000 miles per hour). But there isn’t very much of it. The solar wind is strong enough to push dust and gas away from a comet to make a tail.
The solar wind can even push big things. In 1960, the satellite Echo I was put into orbit. It was a large balloon. Since it was so large and light, the solar wind pushed it around in its orbit. In the future, some space craft may use the solar wind to travel between planets using ''solar sails'' similar to the way sailboats use the Earth's wind in their sails to cross the ocean.
=== Heliopause ===
[[en:Image:Heliopause_diagram.png|thumb|left|200px|Heliopause: where the solar wind hits the edge of the Solar System]]
''Heliopause'' is where the solar wind hits the wind from other stars. Near here, the solar wind slows down suddenly. In May 2005, the Voyager I spacecraft went through this region and felt a big bump. It is now just inside the heliopause. Because this happens so far from Earth, it is hard to study!
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== What is solar weather? ==
Did you know the Sun has weather? Earth weather is what is going on in Earth’s atmosphere. ''Solar weather'' is what’s going on in the Sun’s atmosphere. Solar weather affects us on Earth. Solar weather (also called space weather) includes sunlight and the solar wind.
Solar flares shoot a lot of very hot gas out from the Sun. If a solar flare is aimed towards Earth, protons might be shot at Earth at high speed, and a ''solar storm'' could result. That could cause electrical blackouts or block radio signals. It could damage satellites in orbit. Radiation from a bad solar storm could be very dangerous for astronauts, so they must be protected. The Earth’s magnetic field and atmosphere usually protect us from flares.
[[Image:Aurora1.jpg|250px|thumb|right|Northern Lights]]
Solar flares can also cause an ''aurora''. Auroras look like beautiful curtains of shimmering light. They are called Northern Lights if they are near the North Pole. They are called Southern lights if they are near the South Pole. Solar weather affects other planets, too. We have pictures of auroras on every planet except Mercury and Pluto.
Just like we can get Earth weather forecasts, we can get Solar weather forecasts. Forecasters study the Sun to figure out when flares will happen. They try to tell when solar storms will hit Earth. They also try to tell when solar storms will go to other parts of the Solar System.
==References==
NASA. The Chromosphere - [http://science.msfc.nasa.gov/ssl/pad/solar/chromos.htm]<br>
Col, Jeananda. Enchanted Learning/Zoom Astronomy [http://members.enchantedlearning.com/subjects/astronomy/sun/sun.shtml] 1998-2005<br>
<i>Usborne Internet-Linked Science Encylopedia</i>, Usborne Publishing Ltd. ISBN 0794503314[http://www.usborne.com]<br>
Dickinson, Terrence. <i>The Universe and Beyond</i> . Firefly Books ISBN 1552093611<br>
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[[Luokka:Wikijunior Aurinkokunta|Aurinko]]
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