How fast does the Earth go at perihelion and aphelion?
I need to find the approximate speeds of the earth's orbit at perhilion and aphelion (this year, for example, if it makes a difference). I have given myself a crash course in astronomy over the course of the last three months and command a fair if somewhat pedantic understanding of the underlying principles. The earth's mean revolutionary velocity is easily found, but i have not found these precise figures and am not much of a math whiz. Can you help me?
The formula for the velocity of an object at some distance r from the Sun is:
v = sqrt[GM*(2/r-1/a)]
Where G is the universal gravitational constant, M is the mass of the Sun, and a is the planet's semimajor axis.
At perihelion, Earth's distance from the Sun is r=a(1-e) and at aphelion, it's r=a(1+e).
G=6.673*10-11 N m^2/kg^2
So plugging in the numbers, the speed at perihelion is 30,300 m/s and at aphelion it's 29,300 m/s.
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.
- At what speed does the earth move around the sun?
- How can I find the distance to the Sun on any given day?
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 36136 times since March 20, 2004.
Last modified: March 20, 2004 1:02:15 PM
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)