“sunspot”的概念、定义、翻译、参考文献-科学参考

sunspot

Physics

A dark patch in the sun’s photosphere resulting from a localized fall in temperature to about 4000 K. Most spots have a central very dark umbra surrounded by a lighter penumbra. Sunspots tend to occur in clusters and to last about two weeks. The number of sunspots visible fluctuates over an eleven-year cycle—often called the sunspot cycle. The cause is thought to be the presence of intense localized magnetic fields, which suppress the convection currents that bring hot gases to the photosphere.

Astronomy

A dark area on the Sun’s photosphere that is cooler than its surroundings, associated with very strong (0.4 tesla) magnetic fields. Spots generally appear in pairs or groups, the leading and following spots having opposite magnetic polarities. Spot sizes vary from small pores about 300 km across to groups spanning more than 100 000 km. The largest spots usually last longest, up to 6 months; some small spots may last for less than an hour. Their number varies over the sunspot cycle, being most abundant at solar maximum. Sunspots are mostly confined to belts either side of the equator between about 40° and 5° latitude north and south, appearing at higher latitudes at the start of the sunspot cycle and moving towards the Sun’s equator as the cycle develops. Well-developed spots have a darker interior, the umbra (2), about 1600 K cooler than the photosphere, and a lighter outer penumbra (2), which accounts for up to 70% of the spot’s area and is about 500 K cooler than the photosphere. All spots start their lives as tiny dark pores, and may then develop into small penumbra-less spots arranged in pairs. In a developing group, the spots become much larger and more separated in the first two days, attaining their maximum area and complexity by the tenth day. Broad categories of spot groups can be defined. In the McIntosh scheme, which has replaced the formerly used Zürich scheme, a three-letter code describes the class of sunspot group (single, pair, complex), penumbral development of the largest spot, and compactness of the group. The Mount Wilson scheme is used to describe the magnetic field structure, which may be simple (bipolar or, if a single spot, unipolar) or complex. Spots that give rise to flares tend to be highly complex in appearance and magnetic field structure. Gas flows outwards from spots at low altitudes (the Evershed effect), and inwards at coronal altitudes.
http://sohowww.nascom.nasa.gov/gallery/images/spotcollage.html
http://sohowww.nascom.nasa.gov/gallery/images/sunspot00.html

Space Exploration

A dark patch on the surface of the Sun, actually an area of cooler gas, thought to be caused by strong magnetic fields that block the outward flow of heat to the Sun's surface. Sunspots consist of a dark central umbra, about 4 000 K (3 700° C), and a lighter surrounding penumbra, about 5 500 K (5 200° C). They last from several days to over a month, ranging in size from 2 000 km to groups stretching for over 100 000 km. Sunspot activity waxes and wanes over an 11-year cycle on average.
http://www.exploratorium.edu/sunspots/ Well-written and easily understandable explanation of sunspots. There is a high-resolution image of a group of sunspots and a link for further sunspot pictures. There is information on how to observe sunspots and the Sun's cycle of magnetic activity. For more detailed information there are links to solar observatories.

Geography

A dark patch on the surface of the sun, usually occurring in clusters, and lasting about two weeks. Sunspot activity fluctuates in an eleven-year cycle. It has been suggested that the sun is 1% cooler when it has no spots, and that this variation in solar radiation affects the climates of the Earth; see Schrier and Vesteeger (2001) Geophys. Res. Letts 28, 5.

单词	sunspot
释义	sunspot Physics A dark patch in the sun’s photosphere resulting from a localized fall in temperature to about 4000 K. Most spots have a central very dark umbra surrounded by a lighter penumbra. Sunspots tend to occur in clusters and to last about two weeks. The number of sunspots visible fluctuates over an eleven-year cycle—often called the sunspot cycle. The cause is thought to be the presence of intense localized magnetic fields, which suppress the convection currents that bring hot gases to the photosphere. Astronomy A dark area on the Sun’s photosphere that is cooler than its surroundings, associated with very strong (0.4 tesla) magnetic fields. Spots generally appear in pairs or groups, the leading and following spots having opposite magnetic polarities. Spot sizes vary from small pores about 300 km across to groups spanning more than 100 000 km. The largest spots usually last longest, up to 6 months; some small spots may last for less than an hour. Their number varies over the sunspot cycle, being most abundant at solar maximum. Sunspots are mostly confined to belts either side of the equator between about 40° and 5° latitude north and south, appearing at higher latitudes at the start of the sunspot cycle and moving towards the Sun’s equator as the cycle develops. Well-developed spots have a darker interior, the umbra (2), about 1600 K cooler than the photosphere, and a lighter outer penumbra (2), which accounts for up to 70% of the spot’s area and is about 500 K cooler than the photosphere. All spots start their lives as tiny dark pores, and may then develop into small penumbra-less spots arranged in pairs. In a developing group, the spots become much larger and more separated in the first two days, attaining their maximum area and complexity by the tenth day. Broad categories of spot groups can be defined. In the McIntosh scheme, which has replaced the formerly used Zürich scheme, a three-letter code describes the class of sunspot group (single, pair, complex), penumbral development of the largest spot, and compactness of the group. The Mount Wilson scheme is used to describe the magnetic field structure, which may be simple (bipolar or, if a single spot, unipolar) or complex. Spots that give rise to flares tend to be highly complex in appearance and magnetic field structure. Gas flows outwards from spots at low altitudes (the Evershed effect), and inwards at coronal altitudes. http://sohowww.nascom.nasa.gov/gallery/images/spotcollage.html http://sohowww.nascom.nasa.gov/gallery/images/sunspot00.html Space Exploration A dark patch on the surface of the Sun, actually an area of cooler gas, thought to be caused by strong magnetic fields that block the outward flow of heat to the Sun's surface. Sunspots consist of a dark central umbra, about 4 000 K (3 700° C), and a lighter surrounding penumbra, about 5 500 K (5 200° C). They last from several days to over a month, ranging in size from 2 000 km to groups stretching for over 100 000 km. Sunspot activity waxes and wanes over an 11-year cycle on average. http://www.exploratorium.edu/sunspots/ Well-written and easily understandable explanation of sunspots. There is a high-resolution image of a group of sunspots and a link for further sunspot pictures. There is information on how to observe sunspots and the Sun's cycle of magnetic activity. For more detailed information there are links to solar observatories. Geography A dark patch on the surface of the sun, usually occurring in clusters, and lasting about two weeks. Sunspot activity fluctuates in an eleven-year cycle. It has been suggested that the sun is 1% cooler when it has no spots, and that this variation in solar radiation affects the climates of the Earth; see Schrier and Vesteeger (2001) Geophys. Res. Letts 28, 5.
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