Physics Topic 3 - Waves and the Universe

Physics Topic 3 - Waves and the Universe

1. The Universe

   • Theories about the Universe
     • The Big Bang Theory was one theory (1930s).
       • This theory suggests that everything started out as a tiny point of concentrated energy about 13.5 billion years ago.
         • The universe expanded from this point and is still expanding. As the universe expanded, gravity caused matter to clump together to form stars.
     • The Steady State Theory was another theory (1948).
       • This theory says that the universe has always existed and is still expanding. New matter is continuously created within the universe as it expands.
   • 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.
     • Another way to find things out about the universe is to send a rover to take pictures and collect samples of rocks and soil.
       • 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.
   • The universe is made up of lots of different things, like stars, planets, nebulae and billions of galaxies.
     • The Milky Way is a galaxy.
     • Our Solar System contains eight planets, some dwarf planets, many moons and alot of smaller bodies such as asteroids.
     • You can fit 30 'Earths' between the Earth an the Moon.
     • You can fit over 11,000 'Earths' between the Earth and the Sun.

2. Spectrometers

   • The light from the Sun is a mixture of different colours, forming a spectrum.
     • However, gases in the Sun's atmosphere absorb some of the light in the spectrum and cause dark bands to form.
       • The gases in the Earth's atmosphere can also cause dark bands to form in the Sun's spectrum.
   • Visible light is a mixture of light with different wavelengths and frequencies.
     • 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.
       • A device that contains something that can split up the different wavelengths of light is called a Spectrometer.

3. Alien Life

   • Two Viking Landers touched down on Mars in 1976, and from the data they collected, scientists decided they had found no evidence of life.
   • As all living organisms are dependent on liquid water, that is the first thing scientists look for on a new planet.
   • The Search for Extraterrestrial Intelligence (or SETI) is a name for a series of projects that analyse radio waves coming from space.
     • They look for signals possibly produced by intelligent beings. No messages have been detected so far.

4. Stars

   • Red-shift
     • This is when the stars and planets move away from us.
       • The wavelength is longer behind the source, and shorter in front.
   • The Life-Cycle of Stars
     • The Life-Cycle of a Star like our Sun.
       • Cloud of Gas
         • Protostar
           • Average Star
             • Red Giant
               • Shell of Gas
                 • White Dwarf
                   • End
         • Beginning
     • The Life-Cycle of Massive Stars.
       • Cloud of Gas
         • Beginning
         • Protostar
           • Massive Star
             • Red Supergiant
               • Supernova
                 • Neutron Star
                 • Black Hole
                   • End