EARTH AND SPACE.
1. The Universe Began
2. The Solar System formed
3. The Earth's surface became solid.
4. Multicellular organisms evolved.
PLANETS- are made of rock or gas, and orbit stars.
STARS- are huge balls of hot glowing gas.
MOONS- orbit around planets.
GALAXIES- contain many billions of stars.
STARS ARE MUCH BIGGER THAN PLANETS.
BIGGEST: 1.THE UNIVERSE.
SMALLEST: 5.MOONS, ASTEROIDS AND COMETS.
Evidence that supports the idea of continental drift:
sea floor spreading
the Earth's mantle can flow slowly.
Rocks and Fossils on the West Coast of Africa match those on the East coast of South America.
Volcanoes and Earthquakes are concentrated in certain areas.
STARS AND GALAXIES.
Earth goes around the Sun once every year.
The Earth along with other planets orbiting the Sun is called the Solar System.
The Sun is just one of billions of stars, which form the Milky Way Galaxy- there are billions of other Galaxies forming the Universe.
Distances in Space are so large, they are measured in Light-Years.
Sun and planets are most likely formed from dust, ice and gas. Gravity pulled them together, and at this stage they are called protostars.
Nuclear fusion makes elements such as hydrogen(main fuel) and helium.
Blue stars burn at a higher temperature, fuel runs out quickly, becomes a supernova explosion.
The most common element in the universe is hydrogen.
in stars, it undergoes nuclear fusion to become helium, releasing huge amounts of energy.
What can we tell from looking at the spectrum of the light from a star?
-the chemical elements in that star
- the surface temperature of that star.
Gravitational attraction of atoms to clump together, leading to the formation of stars and planets.
Red-Shift of the light from distant galaxies enables us to measure how fast they are moving away from us- provides evidence for an expanding Universe.