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| | | | | | | Ulysses: the science legacy
12 June 2008
| The heliosphere is the big magnetic bubble in space carved out by the solar wind. It defines the sphere of influence of the Sun and extends well beyond the furthest fringes of the Solar System. The ESA/NASA Ulysses mission has studied it in four dimensions (space and time) for more than 17.5 years.
Credits: ESA (image by C.Carreau) | |  |  | |
| | | | | Before Ulysses, it was know that two types of solar wind existed: one was the fast kind, considered unusual, and the other was the slow wind which was considered more typical. But no one knew how the solar wind varied with solar latitude.
Ulysses found that the fast wind is not so unusual after all: it is basically present throughout the whole 11-year solar cycle and disappears only at solar maximum. At solar minimum (left panel) the fast wind fans out from the poles to fill two thirds of the heliosphere, blowing at an average uniform speed of 750 km/s (see arrows), much faster than the wind that emerges from the Sun’s equatorial zone at 350 km/s. At solar maximum (right panel) the solar wind is more turbulent and irregular.
Credits: ESA | | | | |
| | | | | The Sun’s magnetic field is known to completely reverse in polarity every 11 years. The ESA/NASA Ulysses mission has discovered that this actually happens much more simply than originally thought: the magnetic dipole, similar to a bar-magnet, simply rotates by 180° to accomplish the reversal, as shown in this animation.
Credits: ESA (eclipse images by Wendy Carlos & Fred Espenak) | | | | |
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| | Listen to the press conference  audioMore about... Ulysses overviewUlysses factsheetUlysses operationsRelated videos  The Ulysses legacy (QT player) The Ulysses legacy (WM player)Articles in this release The Ulysses legacySun to set on Ulysses solar mission on 1 JulyUlysses: the engineering challengeMultimedia The Ulysses legacy, in picturesThe Ulysses legacy, multimediaFor the media Joint ESA and NASA statement (pdf)Ulysses factsheet (pdf)PresentationsRelated articles Joint ESA/NASA team wins international awardUlysses mission coming to a natural endIn depth Ulysses in-depthRelated links NASA's Ulysses web site
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