Документ взят из кэша поисковой машины. Адрес
оригинального документа
: http://www.sai.msu.su/apod/ap011108.html
Дата изменения: Unknown Дата индексирования: Tue Oct 2 01:37:45 2012 Кодировка: |
Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.
Explanation: At the Sun's surface, sunspots are known to be dark, planet-sized regions of intense magnetic fields. But what lies below? Using observations from the Michelson Doppler Imager (MDI) instrument aboard the space-based SOHO observatory, astronomers have derived this premier picture of the flow of material just beneath a visible sunspot. The MDI data indicate that immediately under the sunspot a strong inflowing current exists, shown above by the dark arrows. This converging undertow pulls near-surface material toward the spot and prevents the concentrated magnetic fields from flying apart, like repelling poles of iron magnets. Such a configuration appears to divert the normal flow of plasma bubbling up from the solar interior, creating a self-sustaining sunspot. The MDI instrument can explore the properties of the solar interior by detecting motions produced by sound waves as they interact at the solar surface.
Authors & editors:
Robert Nemiroff
(MTU) &
Jerry Bonnell (USRA)
NASA Technical Rep.:
Jay Norris.
Specific rights apply.
A service of:
LHEA at
NASA/
GSFC
&
Michigan Tech. U.