25 November 2015 - Mission Day: 7299 - DOY: 329

SWAN observed a huge cloud of hydrogen, 70 times the size of the Sun, that surrounded Comet Hale-Bopp when it neared the Sun. Ultra violet light, charted by SWAN in 1997, revealed a cloud 100 million kilometres w ide and diminishing in intensity outwards (contour lines). The cloud was generat ed by a comet nucleus perhaps only about 40 kilometres in diameter. The yellow c ircle (lower right) gives the size of the Sun. Solar rays broke up water vapor r eleased from the comet by the Sun’s warmth. The resulting hydrogen atoms shone by ultraviolet light invisible from the Earth's surface.



• European Site • US Site


Feedback & Comments: SOHO Webmaster

Last modification:

SOHO is a project of international cooperation between