Why do some eclipses take longer than others?
Why is it that eclipses have different speeds? The solar eclipse in Christmas 2000 took almost three hours; why?
One reason that eclipses take different amounts of time has to do with whether it is a total eclipse or a partial eclipse, and if it's a partial eclipse, what percentage of the sun is actually being covered. For a total eclipse, the entire disk of the moon has to move across the entire disk of the sun before we would say that the eclipse is "over", but for a small partial eclipse the edges of the disks are only going to graze each other, so it will be over quicker.
Another effect has to do with the distance between the earth and the moon. The moon follows an elliptical orbit around the earth, and the distance between the moon and the earth can vary by something on the order of 10 percent, depending on what part of its orbit the moon is in. When the moon is closer to the earth, it is moving faster; plus, its apparent size on the sky is larger. Both of these affect how long an eclipse will take.
Get More 'Curious?' with Our New PODCAST:
- Podcast? Subscribe? Tell me about the Ask an Astronomer Podcast
- Subscribe to our Podcast | Listen to our current Episode
- Cool! But I can't now. Send me a quick reminder now for later.
How to ask a question:
If you have a follow-up question concerning the above subject, submit it here. If you have a question about another area of astronomy, find the topic you're interested in from the archive on our site menu, or go here for help.Table 'curious.Referrers' doesn't existTable 'curious.Referrers' doesn't exist
This page has been accessed 20809 times since October 8, 2002.
Last modified: October 8, 2002 8:07:34 AM
Ask an Astronomer is hosted by the Astronomy Department at Cornell University and is produced with PHP and MySQL.
Warning: Your browser is misbehaving! This page might look ugly. (Details)