Transcript The Big Bang Theory

The Big Bang Theory
Age of the Earth, Solar System
and Universe
• Universe: 13.8 billion years
• Solar System: 4.6 billion years old
• Earth: 4.5 billion years old
Evidence for the age of the universe
• Life cycle of stars
• Calculating the rate of expansion
• Background microwave radiation
Radioactive Decay
• Radioactive Decay: The decay of radioactive elements
into other elements
• Mass and energy gets released in the form of
radiation
Radiometric Dating
• Radiometric Dating: Uses the rate of decay of
elements to date objects
Evidence for the age of the Earth
• Dating earth rocks, meteorites, lunar rocks
Studying the Sky
• Observation: star gazing, record
keeping, telescopes
The Laws of Physics
• The laws of physics: scientists use the laws of
physics on Earth and then apply that knowledge to
the rest of the universe
Technology
Technology:
• NASA
• Space shuttle flights
• Space telescopes
• International space station
• Robotic spacecraft missions
• Probes
• Orbiters
Steady State Theory
• Steady State Theory: 1917
• The universe is not expanding or contracting
Expanding Universe Theory
• Expanding Universe Theory: 1925
• The universe is continually moving outward
The Big Bang Theory
• The Big Bang Theory: 1927
• 13.8 billion years ago all the matter in the universe
was very hot and dense
• Since then, it has expanded and continues to
expand **current theory**
Evidence for the Big Bang
1. The abundance of light elements
• The ratio of hydrogen and helium we see in the
universe tells us how long ago the Big Bang happened
2. Background Microwave Radiation
• There is microwave radiation everywhere in the
universe left over from the Big Bang
Evidence for the Big Bang
3. The evolution of stars
• Scientists calculate the age of the universe by
observing stars at different stages in their life cycle
4. Hubble’s Red Shift of light data
• Distant galaxies are showing a red shift in light
because they are moving away from our galaxy
Theories about the Future of the
Universe
• The Big Rip Theory
• The expansion of the universe is accelerating and
someday it will be going so fast that matter will tear
itself apart
Theories about the Future of the
Universe
• The Big Crunch Theory
• Someday the universe will reach its maximum and
then matter will start collapsing back in on itself