Other Objects in the
Solar System
 Comets, dwarf planets, meteoroids and asteroids are
important objects in the solar system
A) Trans-Neptunian Objects:
 Trans-Neptunian Object: objects that circle the Sun
beyond Neptune's orbit
 Located in the Kuiper belt (a disc-shaped group of
millions of objects orbiting the Sun)
 Kuiper belt contains fragments left over from
formation of the solar system
B) Pluto:
 Pluto is found in the Kuiper belt
 In 2006, Pluto was demoted to a dwarf planet (after
76 years as a planet) since its orbit sometime's
crosses Neptune's orbit
 Oort Cloud: Small, spherical cloud of icy debris at the
farthest reach of the Sun's gravitational influence
C) Comets:
 Most originate from Kuiper belt or Oort cloud
 When a comet comes close to the Sun, radiation
releases gases and particles, forming a tail
 White coloured comet tails is sunlight reflecting off
particles. Blue tail is ionized gas
 Some comets orbit the Sun and are called periodic
comets
D) Asteroids:
 Asteroid: Small, non-spherical object, often debris
from formation of solar system
 Most orbit the Sun in an asteroid belt
 Range in size: speck (sand) to 500 km wide
 some asteroids have their own moon
E) Meteoroids, Meteors and Meteorites:
 Meteoroids: Pieces of rock moving through space
(chunks of rock broken off of asteroids)
 Meteors: Formed when meteoroids collide with
Earth's atmosphere and burn up
 Meteorites: meteoroids that survive the impact with
the atmosphere and reach the Earth (about 100 000
tonnes of meteorites reach the Earth each year!)
F) Asteroids and Meteorites Impacts:
 65 million years ago, an asteroid the size of a
mountain hit the Earth - extinction of dinosaurs?
 39 million years ago: An object 2km in diameter hit
Devon Island Nunavut Canada creating the Haughton
carter.
 50 000 years ago, an impact produced the Barringer
Crater in Arizona (1000 atomic bombs). Everything
was destroyed within 10km of the crater.
 Tunguska Devastation: June 30 1908, in Tunguska
Siberia, an asteroid 50 m in diameter destroyed a
2000 km2 area