Sunspots

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  • Sunspots
definition
  • An area seen as a dark spot on the PHOTOSPHERE of the sun. Sunspots are concentrations of magnetic flux, typically occurring in bipolar clusters or groups. They appear dark because they are cooler than the surrounding photosphere. Sunspots are classified as to their group characteristics (called the Zurich Sunspot Classification; older sunspot counting schemes may have used the Wolf Sunspot Number classification). Satellite observations of the sun (notably by the ACRIM and ERBE sensors) have demonstrated a correlation between sunspot luminosity changes and sunspot numbers - a possible influencing factor in Earth's climate dynamics.
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Abstract from DBPedia
    Sunspots are phenomena on the Sun's photosphere that appear as temporary spots that are darker than the surrounding areas. They are regions of reduced surface temperature caused by concentrations of magnetic flux that inhibit convection. Sunspots appear within active regions, usually in pairs of opposite magnetic polarity. Their number varies according to the approximately 11-year solar cycle. Individual sunspots or groups of sunspots may last anywhere from a few days to a few months, but eventually decay. Sunspots expand and contract as they move across the surface of the Sun, with diameters ranging from 16 km (10 mi) to 160,000 km (100,000 mi). Larger sunspots can be visible from Earth without the aid of a telescope. They may travel at relative speeds, or proper motions, of a few hundred meters per second when they first emerge. Indicating intense magnetic activity, sunspots accompany other active region phenomena such as coronal loops, prominences, and reconnection events. Most solar flares and coronal mass ejections originate in these magnetically active regions around visible sunspot groupings. Similar phenomena indirectly observed on stars other than the Sun are commonly called starspots, and both light and dark spots have been measured.

    太陽黒点(たいようこくてん、英: sunspot)とは、太陽表面を観測した時に黒い点のように見える部分のこと。単に黒点とも呼ぶ。実際には完全な黒ではなく、この部分も光を放っているが、周囲よりも弱い光なので黒く見える。太陽黒点は、約9.5年から12年ほどの周期で増減を繰り返している。 黒点が暗いのは、その温度が約4,000℃と普通の太陽表面(光球)温度(約6,000℃)に比べて低いためである。発生原因は太陽の磁場であると考えられている。 黒点は太陽の自転とともに東から西へ移動する。大きな黒点群の中には太陽の裏側を回って再び地球から見える側に出てきても消えていない、1か月ほど存在する寿命の長いものがある。(太陽の東西という言葉は地球から観測した場合の地球上での方位を指す。その天体に立った場合の方位ではない)

    (Source: http://dbpedia.org/resource/Sunspot)

data publication(s) found by GCMD Science Keywords)