11th April 2011 Comet Elenin

A while ago, someone posted a link to a video of a woman predicting an earthquake when the Japanese quake occurred. She said that it was because comet Elenin, the earth and the sun were in a straight line.

Here are some facts about Elenin.

•  The closest Elenin will come to us is 0.24 AU - that is slightly closer than the closest Venus gets to us and (100 x distance to moon).
•  Elenin passed its closest on 2nd April 2011, and its orbit remains unchanged.
• It's tidal force is 1/billion times that of the moon so it wont cause Earthquakes - not even the moon does that!
• We may pass through its tail, but that is smaller than Halley's tail. 
• It's around 3-4 km in diameter.
• It may evaporate (thought to be 50% chance) when it gets nearer to the sun as it's either a dirty snowball or icy dirtball, possibly barely holding together.

1st April 2011 Seeing Impacts in Planet Rings

Over the years, lines have been observed in the rings of Jupiter.  These lines can be traced back to when a comet is known to have hit Jupiter in 1993.

Sources

1. SETI - How to Catch a Comet
2.  Greg Laden - Ripples in Planetary Rings Are Traces of Decades-Old Cometary Collisions
3.  NASA - Forensic Sleuthing Ties Ring Ripples to Impacts