The DDAS Astronomical Dictionary
Glossary of astronomical terms aimed at all levels of learning.
www.geocities.com/kev_woodward/   Science: Astronomy: Amateur: Beginners  

The Astronomy Thesaurus
Astronomical terms. Searches may be performed in English, French, German, Italian, and Spanish.
www.mso.anu.edu.au/library/thesaurus/   Reference: Thesauri: By Subject  

Close shave with asteroid
A large asteroid could miss the Earth by only 38,000 kilometres in 2027, according to new astronomical observations. What's more it will remain dangerously close for about 600 years, and chaos theory means that it is impossible to predict its trajectory with enough accuracy for more than a few decades in advance.
news.bbc.co.uk/1/hi/sci/tech/347764.stm   Society: Future: Catastrophes: Large Near Earth Object Impacts  

Glossary
Glossary of comet terms.
cfa-www.harvard.edu/icq/ICQGlossary.html   Science: Astronomy: Solar System: Small Bodies: Comets  

Mission to Mars with Bill Nye
See why Mars is so fascinating to many astronomical scientists. Includes photos of the rover and the planet, as well as a glossary of terms and timeline.
athena.cornell.edu/kids/   Kids and Teens: School Time: Science: Astronomy and Space: Exploration  

Anglo-Australian Observatory
The AAO operates the Anglo-Australian and UK Schmidt telescopes on behalf of the astronomical communities of Australia and the UK. Has an online catalogue, astronomy preprints, newsletters, links to astronomy journals, and a thesaurus of astronomy terms.
www.aao.gov.au/   Regional: Oceania: Australia: Government: Executive Powers: Education, Science and Training