1. Chapter 26 What is Out There?

2. New Words Universe Space Galaxy Star Solar System Planet Moon Asteroid
Comet
Meteor
Meteorite
Black hole
Constellation

3. The Universe describes everything that exists
The Universe describes everything that exists. Space is the empty regions between bodies in the universe. Galaxies are collections of hundreds of billions of stars. Galaxies are either elliptical or spiral. Spiral galaxies are flat in one direction and oval in the other. They have spiral arms and sometimes a bar across the centre.

4. Elliptical galaxies are oval shaped no matter which direction you look at them. They are similar to the shape of a rugby ball. Our galaxy is called the Milky Way. The closest spiral galaxy to us is the Andromeda Galaxy. Scientists say there are between 100 billion – 400 billion stars in the Milky Way.

5. Scientists can estimate the mass of a galaxy by examining the way it rotates. Stars are giant balls of hot gas which give out huge amounts of heat and light. Our sun is an ordinary star in our galaxy. Orange stars are called red giants. Other hotter stars are called super giants

6. Nicolaus Copernicus – he realised that the planets were orbiting the sun. Planets nearer the sun move faster than planets further away. Planets – objects that have enough gravity to pull themselves into a round shape. 8 planets in our solar system – Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune.

7. Asteroids Giant rocks that orbit the sun and are too small to be called planets Three quarters of asteroids are located in the asteroid belt between Mars & Jupiter. Giant asteroid struck the earth 65 million years ago. The dust from this asteroid blocked out the sun and may have deprived dinosaurs of food

8. Comets Comets are made from mixtures of frozen gases, ice, dust and small rocks. They usually orbit the sun in elliptical Orbits. The most famous comet is Halley’s Comet and it is only visible from earth every 75 years.

9. Meteors
Rocks that burn up in the earth’s atmosphere leaving shooting star trails behind them

10. Black holes Black holes are invisible collapsed stars with huge masses
Black holes Black holes are invisible collapsed stars with huge masses. Gravity is really strong in black holes and they pull everything is even light. It is believed that most galaxies have supermassive black holes at their centre .

11. Jocelyn Bell Astronomer who heard a regular pulse from a radio telescope. This pulse was identified as a pulsar or neutron star. A neutron star is a collapsed star that spins rapidly and fires out radiation.

14. Constellations Groups of stars with no real connection which historically have been joined together in a kind of giant join the dots. Famous constellations e.g. Ursa Major Great Bear In ancient times it was Believed that astronomy (scientific study of space) and astrology (predicting your future based on events in the night sky) were all part of the same thing.