[Under Construction]



Solar-System Debris


Key Terms:

Notes: (27-4)

Other than suns, planets, and moons, our solar system consists of various types of rocks and debris.  The impact of these debris on the planets and moons give them the distinct features that have been recorded.


Comets are often called dirty snowballs - made of dirt nuclei and frozen gasses and water
Most exist outside Neptune in a region called the Edgeworth-Kuiper belt
Also referred to as TNOs - Trans Neptune Objects
few have elliptical orbits that move them close to the sun
forms a coma - large cloud of dust and gas expanding out to space
the coma always points away from the sun - precedes the retreating comet
Halley's comet returns every 75 years

Halley's Comet(www.project2061.org/images/ home/comet.jpg)

How a meteoroid stream is created.(www.uwo.ca/wnews/centre/ comets.jpg)


irregular fragments of rock
most are less than 1 km long
most revolve around the sun in the same direction as the planets in the asteroid belt between Mars and Jupiter
few have elliptical orbits and have collided with planets in the past
65 million years ago with Earth - extinction of the dinosaurs

Click here to display a full-sized version of the image(bruckner.homelinux.net/ images/solsys.jpg)

Meteoroids and Meteors

a meteoroid is a fragment of rock or ice that is traveling in space
can be grain sized  to 100 m across
smaller than an asteroid 
once the meteoroid comes in contact with Earth's atmosphere it becomes a meteor
sometimes a shooting star
meteor showers are when large numbers of meteoroids enter our atmosphere at the same time
often occurs as Earth passes through the tail of a comet
Meteorite is the part of the meteor that reaches the Earth
three types
look like dark igneous rocks
made primarily of silicates
made primarily of iron and nickel
formed when the molten iron and stony meteors come in contact with each other

Impact Crater

bowl-shaped depression that remains after a meteorite strikes the Earth
~150 known on Earth's surface
Arizona's Barringer Meteor Crater
49,000 yrs ago
iron meteorite ~ 45 meters in diameter
left a crater 1200 meters in diameter

Barringer Meteor Crater(cfa-www.harvard.edu/cfa/ ep/meteor/barringer.jpg)








Last modified: May 16, 2003