Sunday, January 24, 2010

Retrograde orbit

Learned today--retrograde orbit--used to describe a planet which rotates in the opposite direction as the rotation of it's star.

Also learned, in trying to figure out what that means--stars rotate about their axes! And thus the sun, Sol, rotates about its axis (I was tempted to add an incorrect apostrophe in "its" there, just to annoy other nitpickers like me.) Morever, it's rotation is differential, which means it rotates at different speeds at the equator and the poles--a rotation every 27 days at the equator, and a rotation every 31 days at the poles. Given the circumference of the sun at the equator, this means that anyone standing on the equator is not only moving enormously faster than someone standing near the pole--they are moving *even more* enormously faster. Kewl. What is the speed of someone standing on the equator of the sun relative to the sun's axis?

If a dude stands at the pole, and another dude stands at the equator, so that they are on the same longitude, then given the differential rotation, what is the period between which they first are on the same longitude and they again are on the same longitude? Hmmmmmm.

Feel tiny yet?

How does the goldilocks zone of VY Canis Majoris compare to the Goldilocks zone of Sol, in AU?
I bet it's *way* further out.

1 comment:

  1. I just discovered that my Kaspersky Banner Ad blocker won't allow the embeded comments form to open for blogs I am following (like this one) until I added to my white list. In other words, Blogger blogs actually work against me for being a follower of your blog.

    Blogger blogs that use a different style of comment form weren't affected.

    I think this happened on my blog a few months back when one of my followers couldn't access my comments after I tried switching to the embedded comments form (so I went back to the pop-up form.)

    I just wanted to post this in case others have run into a similar problem.