![Earth’s full north polar auroral oval, in an image taken in ultraviolet light by the U.S. Polar …[Credits : NASA]](http://media-2.web.britannica.com/eb-media/10/76810-004-DE63D1C8.jpg)
Earth’s full north polar auroral oval, in an image taken in ultraviolet light by the U.S. Polar spacecraft over northern Canada, April 6, 1996. In the colour-coded image, which simultaneously shows dayside and nightside auroral activity, the most intense levels of activity are red, and the lowest levels are blue. Launched in February 1996, Polar was designed to further scientists’ understanding of how plasma energy contained in the solar wind interacts with Earth’s magnetosphere.
Link to this article and share the full text with the readers of your Web site or blog-post.
If you think a reference to this article on "" will enhance your Web site,
blog-post, or any other web-content, then feel free to link to this article,
and your readers will gain full access to the full article, even if they do not subscribe to our service.
You may want to use the HTML code fragment provided below.
We welcome your comments. Any revisions or updates suggested for this article will be reviewed by our editorial staff. Contact us here.
Regular users of Britannica may notice that this comments feature is less robust than in the past. This is only temporary, while we make the transition to a dramatically new and richer site. The functionality of the system will be restored soon.