Comets are the theme for this week, starting with a new background article.
Ill omens, objects of fascination, bringers of life, key to the ancient history of the Solar System. Comets are all of these things. Find out more about these small Solar System bodies.
July 2, 1985: Giotto launched
Twenty-five years ago this Friday, the European Space Agency (ESA) launched the Giotto probe to study Comet Halley. It went on to make the first close approach to a comet and photograph its nucleus. Afterwards it did a fly-by of Comet Grigg-Skjellerup. For more information about this mission, click on the link http://www.esa.int/science/giotto
July 4, 2005: Deep Impact probe hits Comet Tempel 1
For readers in the USA--and Americans abroad--Happy Fourth of July! Five years ago NASA celebrated in style when the probe from the Deep Impact mission was collided with Comet Tempel 1. Yes, that was planned, in order to learn more about its structure. Here is a link to a NASA video of the event: http://preview.tinyurl.com/3xc7wca
Comet McNaught (C/2009 R1)
There has been a comet visible recently and there may still be a chance to see it. It's not brightened to be a naked eye object, but people with telescopes (and clearer skies than I have) have taken some pictures. You can see a number of them here. It's worth scrolling down to see Michael Jager's color images: http://cometography.com/lcomets/2009r1.html
This comet hasn't turned out to be as exciting as the Great Comet of 2007, also discovered by Robert McNaught. Some people got a good view of that one when it was visible from the northern hemisphere, but it really became a spectacular southern hemisphere sight. It stopped traffic and got reported as a bush fire. Here is a link to the Astronomy Picture of the Day: http://apod.nasa.gov/apod/ap070122.html
Calling all teachers, kids and geeks of all ages!
Interactive Comet Animation. This is an interactive exploration of comet orbits. Some named comets are included, but you can also see what happens if you change the distance and the shape of the orbit. It was rather impressive to see the way the comet speeds up going around the Sun. And remember to speed up the simulation for large orbits unless you're very patient. http://www.windows2universe.org/comets/comet_model_interactive.html&edu=high
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Mona Evans, Astronomy Editor