The Universe EoY

• Universe began 13.787 billion years ago

  • All of space-time and energy in a singularity

• Upon the big bang, the singularity exploded

  • Became cooler and less dense as it spread rapidly

    • Spreading space-time with it

• Due to immense temperature (upwards of 10^32 K)

  • All forces were unified

• Universe cooled

  • Some matter remained from slight imbalance of matter to antimatter

Evidence for the big bang theory:

1. Redshift

   1. Light we observe from galaxies has been stretched by the time it has reached us

      1. Increased wavelength

   2. See it in every direction

   3. Tells us that the universe is expanding

   4. Same as doppler effect

      1. Effects light instead of sound

   5. Waves can be described with ‘wavelength’

   6. higher the wavelength

      1. more red

      2. visible light

   7. lower the wavelength

      1. more blue

      2. visible light

   8. object moving away from us

      1. wavelength stretched

      2. becomes larger

      3. makes it look more red

2. Hubbles Law

   1. The further away a point is from “home” the further it moves away when expansion is occurring

   2. The further away we measure the star to be the faster it is moving away

   3. Looking Back in Time

      1. Light takes time to travel

         1. We are always looking back in time

         2. Further away the star the further back in time we observe it

      2. Mixture of elements

         1. Inside stars and planets

         2. Changes depending on its age

         3. Abundance of hydrogen and helium in old galaxies

            1. Supports the big bang theory

      3. See old galaxies are different to new ones

         1. Rule out steady state theory

            1. States the universe hasn’t changed at all

3. Cosmic Microwave Background Radiation (MBR)

   1. Type of radiation always present

      1. When we measure waves emitted from distant places in space

   2. Leads to the idea that it is leftover radiation created during the Big Bang

      1. Now exists across the universe

   Contributions of Brian Schmidt and Gravity:

   Historical Understanding:

   • Gravity has been considered a fundamental force

     • Alongside strong nuclear, weak nuclear and electromagnetic

   • Gravity is an effect of the gravitational field

     • All mass has and creates

   • Objects with large mass create stronger fields

     • Attracting large objects

   • Gravity is the weakest of the force

     • Controls masses

   • Electromagnetic

     • Waves

       • Radio

       • Gamma

       • Visible

   • Strong

     • Tiny things attract to each other

     • Brings together small things

       • Protons

   • Weak

     • Radioactivity

     • Radioactive decay in atoms

   Modern Interpretation of Gravity:

   • Is not a force but an element of spacetime

   • Reality is woven from spacetime

     • Objects with higher mass causes higher “wells” in spacetime

     • Causes objects to curve and change their course

       • Without being a force

• Early Indigenous People

  • Lived at varied times, thousands of years ago (prior to recorded history).

  • Observed celestial bodies for navigation, agriculture, and spiritual practices.

  • Used star patterns and knowledge of lunar cycles to mark time and seasons.

• Aristotle

  • Lived from 384–322 BCE.

  • Developed the geocentric model (Earth-centered).

  • Believed Earth was at the center of the universe, with planets and stars revolving around it.

• Ptolemy

  • Lived around 100–170 CE.

  • Expanded on Aristotle's geocentric model.

  • Developed the Ptolemaic model with epicycles to explain planetary motion.

  • Described his model in his work Almagest.

• Copernicus

  • Lived from 1473–1543.

  • Proposed the heliocentric model (Sun-centered).

  • Asserted that planets, including Earth, orbit the Sun.

  • Published his ideas in De revolutionibus orbium coelestium in 1543.