Earth, Our Environment - Class Notes
Chapter 2, Earth: Origin and Composition - 01
The Big Bang Hypothesis

The fundamental particles that make up everything we know to exist were created at the formation of the Universe, which began with the "Big Bang". Approximately 15 billion years ago (actually 10-20 billion is the estimate), the Universe exploded into existence.

The observational evidence for the Big Bang includes:

The universe-forming "bang" was enormously energetic and the resulting temperature was high. Elementary particles existed for fractions of a second and began to coalesce with time, forming the familiar particles of atomic physics. Additionally, the fundamental forces in the Universe began united in one system:

Elapsed Time


10^-43 second

Quarks and Bosons be come interchangeable & Gravity force separates

10^-35 second

Electroweak and strong forces separate

10^-10 second

Weak and electromagnetic forces separate

1st millisecond

Particles form from quarks

3-4 minutes

Hydrogen and Helium nuclei form

1 billion years

Protogalaxies form

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Prepared by: Charles J. Ammon
February 1997