What's New?

Bad Astronomy

BA Blog
Q & BA
Bulletin Board

Bitesize Astronomy
Book Store
Bad Astro Store
Mad Science
Fun Stuff
Site Info

Search the site
Powered by Google

- Universe Today
- The Nine Planets
- Mystery Investigators
- Slacker Astronomy
- Skepticality

Buy My Stuff
Bad Astronomy at
Keep Bad Astronomy close to your heart, and help make me filthy rich. Hey, it's either this or one of those really irritating PayPal donation buttons here.

Subject: Why does comet dust spread out along the comets orbital path?

Date: Fri Dec 8 17:22:10 2000
Posted by Fred
Grade level: grad (science) School: No school entered.
City: Macungie State/Province: PA Country: USA

I understand that meteor storms occur when the Earth passes through the dust along a comet's path. How does that dust get distributed along the comet's orbital path? I would think that particles traveling slower or faster than the comet would take different paths.

Comets are theorized to be ``dirty snowballs'', that is, lumps of rock and dust all held together by frozen gases. As they near the Sun, the gas can melt (or sublimate; go right to vapor) which loosens the other junk. Bits and pieces of the comet can then drift away from the parent comet.

There are forces on these flotsam. The solar wind is one, and light pressure from the Sun is another. These are fairly gentle forces, and can push the castoff material away from the comet. They do indeed take on new orbits, but the bigger material doesn't change all that much. Over centuries, the orbits can drift quite a bit, but there is usually still a clear tie to the parent comet, because there are characteristics of the orbits that are similar, like ellipticity, time of perihelion (closest to the Sun) passage and the like.

There are many websites about comets and meteors. Try Gary Kronk's Comets & Meteor Showers site, or The International Meteor Organization for more info.

©2008 Phil Plait. All Rights Reserved.

This page last modified


Q&A 1996

Q&A 1997

Q&A 1998

Q&A 1999

Q&A 2000

Subscribe to the Bad Astronomy Newsletter!

Talk about Bad Astronomy on the BA Bulletin Board!