This document discusses different celestial objects in space including comets, asteroids, meteoroids, meteors, meteorites, moons, stars, and our solar system. Comets are icy objects that develop tails when close to the sun, while asteroids orbit in a belt between Mars and Jupiter. Meteoroids enter Earth's atmosphere and become meteors, some surviving as meteorites. Moons orbit planets, and stars like Polaris, Sirius, and Betelgeuse are the nearest stars to our solar system. Space probes like Voyager have explored beyond our solar system.

1. Celestial Objects
in Space

2. Comets
 chunks of frozen gases,
rock & dust that orbit the
sun
 tail is formed when the
comet comes close to the
Sun
Comet Shoemaker-Levy 9 hit Jupiter in 1994.

3. Asteroids
 Irregular shaped rocky
objects
 many orbit around the Sun
and this is called an asteroid
belt

4. Meteors & Meteorites
 A meteoroid is a clump of rock or metal which is
pulled towards Earth by gravity
 In Earth’s atmosphere it heats up, begins to glow
and becomes a meteor
 If the object is not vaporized before it contacts the
Earth’s surface it is called a meteorite
meteoroid meteor meteor shower

5. Asteroid: -Small; inactive
- made of rock, carbon or metal
- Orbits the sun
Comet: - small; sometimes active object
- made of dirt, gas and ice
Meteoroid: - small particle from an asteroid or comet
- orbits the sun
Meteor: - A meteoroid that burns up in the Earth's
atmosphere - a shooting star.
Meteorite: - A meteoroid that survives its passage
through the Earth's atmosphere and impacts
the Earth's surface.
What’s the difference?

6. Moons/Satellites
 Large natural objects which revolve
around a planet
 many planets have more than one
moon
 Earth’s moon has no atmosphere and
has hills/valleys/craters
 after the invention of the telescope
Galileo saw 4 moons of Jupiter
 Moons can come in a variety of size
and with a variety of surfaces

7. Stars
 A STAR is a luminous ball of plasma that is held
together by gravity.
 What is the nearest star to Earth?
 What is the nearest star to the Sun?

8. Binary Solar System

9. Stars
 Polaris
 pole star for the Northern Hemisphere
 390 light years from Earth
 part of a binary star system
 Sirius
 the brightest star in the sky (70 times more
luminous than the sun)
 8.6 light years from the Earth
 Betelgeuse
 one of the brightest stars in the sky
 supergiant
 1,000 times bigger than the Sun but cooler than
the Sun

10. Outside our Solar System
 Voyager I, Pioneer 10 & 11
andVoyager 2 built to
explore outside our solar
system
 Took 20 years to leave solar
system
 will reach the nearest star in
50 000 years