Physics Topic 3 - Waves and the Universe

The Universe
1. Theories about the Universe
  1. The Big Bang Theory was one theory (1930s).
    1. This theory suggests that everything started out as a tiny point of concentrated energy about 13.5 billion years ago.
      1. The universe expanded from this point and is still expanding. As the universe expanded, gravity caused matter to clump together to form stars.
  2. The Steady State Theory was another theory (1948).
    1. This theory says that the universe has always existed and is still expanding. New matter is continuously created within the universe as it expands.
2. We can't see much of space with the human eye, we have to use telescopes to be able to see things far away and be able to see things in more detail.
  1. Another way to find things out about the universe is to send a rover to take pictures and collect samples of rocks and soil.
    1. As well as using normal telescopes, we can use telescopes that go into space like The Hubble Telescope that has been orbiting the Earth since 1990.
3. The universe is made up of lots of different things, like stars, planets, nebulae and billions of galaxies.
  1. The Milky Way is a galaxy.
  2. Our Solar System contains eight planets, some dwarf planets, many moons and alot of smaller bodies such as asteroids.
  3. You can fit 30 'Earths' between the Earth an the Moon.
  4. You can fit over 11,000 'Earths' between the Earth and the Sun.
Spectrometers
1. The light from the Sun is a mixture of different colours, forming a spectrum.
  1. However, gases in the Sun's atmosphere absorb some of the light in the spectrum and cause dark bands to form.
    1. The gases in the Earth's atmosphere can also cause dark bands to form in the Sun's spectrum.
2. Visible light is a mixture of light with different wavelengths and frequencies.
  1. These different wavelengths can be split up using a prism, or by something that has lots of fine lines on it, such as a CD or DVD.
    1. A device that contains something that can split up the different wavelengths of light is called a Spectrometer.
Alien Life
1. Two Viking Landers touched down on Mars in 1976, and from the data they collected, scientists decided they had found no evidence of life.
2. As all living organisms are dependent on liquid water, that is the first thing scientists look for on a new planet.
3. The Search for Extraterrestrial Intelligence (or SETI) is a name for a series of projects that analyse radio waves coming from space.
  1. They look for signals possibly produced by intelligent beings. No messages have been detected so far.
Stars
1. Red-shift
  1. This is when the stars and planets move away from us.
    1. The wavelength is longer behind the source, and shorter in front.
2. The Life-Cycle of Stars
  1. The Life-Cycle of a Star like our Sun.
    1. Cloud of Gas
      1. Protostar
        Average Star
        Red Giant
        Shell of Gas
        White Dwarf
        End
      2. Beginning
  2. The Life-Cycle of Massive Stars.
    1. Cloud of Gas
      1. Beginning
      2. Protostar
        Massive Star
        Red Supergiant
        Supernova
        Neutron Star
        Black Hole
        End

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Physics Topic 3 - Waves and the Universe

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