The Straight Dope

Go Back   Straight Dope Message Board > Main > Comments on Cecil's Columns/Staff Reports

Reply
 
Thread Tools Display Modes
  #1  
Old 05-07-1999, 08:14 AM
Guest
 
The column about "Why does the same side of the moon always face the earth?" says that "captured" or "synchronous" rotation...[is] common throughout the solar system.

How common is it? Of all the moons that we can see clearly enough to detect their rotation, what percentage do not appear to rotate when viewed from the surface of the planet?
Reply With Quote
Advertisements  
  #2  
Old 05-07-1999, 11:16 AM
Guest
 
Most of the astronomy pages I found use the same word Cecil did, "most". In particular, the following page on Saturn, http://tthep1.phys.ttu.edu:8003/www/solar/saturn.htm, says 16 of Saturn's 18 positively identified moons are synchronous. http://www.news.cornell.edu/releases...ter.facts.html says all 16 of Jupiter's moons are synchronous. And http://www.yucc.yorku.ca/~troy/io/io.html makes the bold claim that All the satellites of the outer planets with radii > 200 km are in synchronous rotation with respect to their host planet
Reply With Quote
  #3  
Old 05-07-1999, 01:18 PM
Guest
 
Interesting info on planets that cannot support life and have a big advantage in gravitational pull. If you only consider the smaller, inner planets (acknowledging that Mercury could never support life and Venus can't with it's present atmosphere), do their residents gaze on static or rotating moons?
Reply With Quote
  #4  
Old 05-07-1999, 01:53 PM
Guest
 
well, as neither Mercury nor Venus have companion bodies, it is kinda hard to tell. I don't know about the puny rocks Mars captured, but as the Moon is the only satellite in the inner system of any appreciable size I would say the statement is confirmed and valid.
Reply With Quote
  #5  
Old 05-07-1999, 02:10 PM
Guest
 
About Mars--this link reports Phobos to be synchronous, I'm not sure about the other moon, but I would guess it is too. In any event, the Martian moons are so small they just look like bright stars from the planet surface. http://www.csr.utexas.edu/tsgc/archi...ns/phobos.html
Reply With Quote
  #6  
Old 05-07-1999, 02:43 PM
Guest
 
The reference about Mars actually said:
"They have nearly circular, equatorial orbits, and their rotations are locked to their orbital motions, so that each always turns the same face to Mars, as the Moon does to Earth."

Statistically, that about clinches it. I'm forced to conclude that any other "intelligent" beings on other planets probably gaze at a flat, static, plate-like moon(s) over their planet. This means that they probably developed their own version of the "flat Earth" theory.
Reply With Quote
Reply

Bookmarks

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is Off
HTML code is Off
Forum Jump


All times are GMT -5. The time now is 09:06 PM.


Powered by vBulletin® Version 3.7.3
Copyright ©2000 - 2013, Jelsoft Enterprises Ltd.

Send questions for Cecil Adams to: cecil@chicagoreader.com

Send comments about this website to: webmaster@straightdope.com

Terms of Use / Privacy Policy

Advertise on the Straight Dope!
(Your direct line to thousands of the smartest, hippest people on the planet, plus a few total dipsticks.)

Publishers - interested in subscribing to the Straight Dope?
Write to: sdsubscriptions@chicagoreader.com.

Copyright © 2013 Sun-Times Media, LLC.