Plus, although the pretty but basically harmless meteor showers such as the Perseids do <i>predominantly</i> strike the leading side of the planet, they aren't limited to it, and more dangerous meteorites can come from any direction at all. <img src="/images/icons/shocked.gif" /> It's not the meteor showers you have to worry about -- it's the isolated minor planets (asteroids, comets, etc) with orbits that cross the orbit of your own planet that have the potential to cause major devastation.<br /><br />Now as to the first question....<br /><br />Is there a planet which rotates synchronously, as the Moon rotates synchronously? (Note: such objects DO rotate. It's just that they take the same amount of time to rotate as they do to complete one orbit, so they always face the same side to their parent.) For a long time, Mercury was believed to rotate synchronously, but the advent of doppler radar techniques in the 60s disproved that. It <i>does</i>, however, have a resonance between its rotational period and its orbital period -- for every three Mercury days, there are exactly two Mercury years. It is the only body ever discovered with a rotational-to-orbital resonance other than 1:1 (which is synchronous).<br /><br />Lots of moons are synchronous, however, including our Moon, Io, Europa, Ganymede, Callisto, almost all of Saturn's moons with known rotational periods (apart from Phoebe and Hyperion, which are probably captured asteroids), and Pluto's moon Charon. Charon is actually very interesting case. Like our Moon, it is very large relative to its parent body, which means it has a significant tidal effect on its parent. Over time, Pluto and Charon have become <i>mutally synchronous</i> -- they always face one another. One Pluto day, one Charon day, and one Charon "month" are all the same length. An observer on Pluto would see Charon fixed motionless in the sky while the stars wheeled past in the background and Charon went through its phases. Someday in the distan <div class="Discussion_UserSignature"> <p> </p><p><font color="#666699"><em>"People assume that time is a strict progression of cause to effect, but actually from a non-linear, non-subjective viewpoint it's more like a big ball of wibbly wobbly . . . timey wimey . . . stuff."</em> -- The Tenth Doctor, "Blink"</font></p> </div>