The Big Bang Theory

1. The Big Bang Theory By Stefanie Pacheco Astronomy

2. How old is the Universe? • Scientists approximate the universe to be about 15 billion years old. • We do not see the whole universe, we do not know how big it is.

3. Our Horizon • We can only see as far as light can travel. • We cannot see galaxies that are more than 15 billion years old because they have not yet entered our horizon.

4. How did it all start? • 0 • The Universe started out very small and very dense.

5. Inflation • 10-32 seconds • The universe underwent an initial inflation that lasted a infinitismle fraction of a second. Which means it expanded much faster than the speed of light.

6. Causes of Electrons • The Universe was very hot, atoms couldn’t exist. • Electrons caused very small packets of light called photons to scatter continuously, light was linked to the particles, causing the whole universe to glow.

7. Quark Soup • 1 Second • Universe looked like a plasma “soup” of protons, electrons, neutrons, neutrinos, photons, etc.

8. Big Freeze Out • 300,000 years • Things start to cool off as they expand off, as the universe continued to expand it cooled off. • 300,000 years passed and it cooled off enough so atoms could form.

9. Parting Company • Photons scattered ionized particles like protons and electrons • Photons traveled through space in straight paths instead of constantly being scattered by electrons.

10. Parting Company • This lead to the formation of the elements, hydrogen and helium. • Photons made up a uniform light radiation that filled the whole universe.

11. First Galaxies • 1 Billion Years • Regions of the universe became very dense. • Gravity overcame the expansion and formed galaxies and galaxy clusters.

12. The Milky Way • Our own galaxy • Part of a galaxy of clusters

13. Modern Universe • 12-15 Billion Years • The universe today is observed to contain one helium atom for every ten or eleven atoms of hydrogen. 

14. Tour of the Universe