Dactyl (moon)

From Wikipedia, the free encyclopedia

Jump to: navigation, search
243 Ida (left) and Dactyl (right), as photographed by the Galileo spacecraft.
243 Ida (left) and Dactyl (right), as photographed by the Galileo spacecraft.

(243) Ida I Dactyl (pronounced[help] /ˈdæktɨl/ dak'-tl) is a tiny asteroid moon (diameter 1.4 km) that orbits asteroid 243 Ida. It was imaged by the Galileo spacecraft on August 28, 1993; the Galileo mission member Ann Harch, while examining the delayed image downloads, discovered it on February 17, 1994. It was provisionally designated S/1993 (243) 1. The satellite was named after the mythical creatures called dactyls who lived on the Mount Ida according to the Greek mythology.

Dactyl orbits Ida with a period of 1.54 days at an average distance of 108 km, with an inclination of 9° to Ida's equator. The orbit is not very accurately known because Galileo coincidentally passed very nearly in its plane while taking the images.

The origins of Dactyl are unclear, but two main hypotheses exist. The first is that Dactyl and Ida formed at the same time, and the second is that Dactyl was knocked loose by a later impact. Both hypotheses have problems and cannot explain the situation satisfactorily.

Detailed image of Dactyl
Detailed image of Dactyl

Dactyl was the first asteroid moon discovered. The discovery settled the long debate over the existence of asteroid moons.

Advanced Search
Included Web Search Engines


Safe Search

close

Top Matching Results

Occasionally Search.com will highlight specialized results that are based on the context of your query. Examples of specialized results include specific links to news, images, or video.

Top Matching Results may highlight information from other Search.com pages, content from the CNET Network of sites, or third party content. The listings are based purely on relevance. Search.com does not receive payment for listings in this section but our partners that provide this data may get paid for listing these products.

Sponsored Links

This section contains paid listings which have been purchased by companies that want to have their sites appear for specific search terms and related content. These listings are administered, sorted and maintained by a third party and are not endorsed by Search.com.

Search Results

Search.com sends your search query to several search engines at one time and integrates the results into one list which has been sorted by relevance using Search.com's proprietary algorithm. You can customize the list of search engines included in your metasearch from the preferences.

The search engines that are used in your metasearch may allow companies to pay to have their Web sites included within the results. To view the Paid Inclusion policy for a specific search engine, please visit their Web site. Search.com does not accept payment or share revenue with any search engine partner for listings in this section.