Overview of Modern Physics
• Light
• General Relativity
• Quantum Mechanics
• The Big Bang
Light
• Perhaps the most interesting and necessary to support life
• Comes in many forms
• Can act as a wave or a particle (unique!)
• Light can act like a wave (ex: sound or water)
• Light can act like a particle (ex: basketball)
• Light seems to know the fastest path through a material
• The speed of light is a well-known quantity and is considered the “speed limit of the Universe”
General Relativity
• Has been verified enough to use in everyday items like GPS
• Gravity can bend light and make “impressions” in space-time
Quantum Mechanics
• Useful when talking about microscopic things
• Shows that electrons do not orbit a nucleus like a planet around the Sun
• Gives probabilities for direction and location at any given time
Imagine that you reach your hand out to touch a table:
• On a microscopic level, what you feel as “solid” is actually the electrons in your hand repelling the electrons in the table
• Theoretically, your hand could pass through the table if you could line up the electrons in your hand with the electrons in the table (quantum tunneling)
The Big Bang
• Some ancient pagans (like Aristotle) believed that the Universe always existed — called a “steady state” Universe
• This view is attractive for modern atheists because it does not require a beginning to the Universe
Kalam Cosmological Argument
• John Philoponus of Alexandria (4th century) was a Christian philosopher who argued that the Universe had a beginning
• Islamic philosophers preserved this argument in the Middle Ages
• Jewish scholars brought this back to Europe at the end of the Middle Ages
• Whatever begins to exist has a cause.
• The Universe had a beginning.
• Therefore, the Universe has a cause.
Atheists are motivated to show the Universe did not have a beginning!
The Big Bang
• Alexander Friedmann used Einstein’s theory of general relativity to propose an expanding Universe
• Catholic priest and professional astronomer Georges Lemaitre proposed what would later be called “the Big Bang theory” in 1927 using Einstein’s theory of general relativity and Friedmann’s expanding model
• This basic model is still being tested and tweaked today
• In 1929, Edwin Hubble discovered that far-away stars are “red-shifting” in every direction
• This only makes sense if the Universe is expanding
• If we extrapolate backwards, we end up with a fixed point at the beginning of the Universe!
• Atheists were quick to propose an alternative solution: what if the Universe was expanding, but matter is continuously created to keep the average density the same?
• This is called the “steady state” hypothesis
• This would allow for an infinitely old Universe
• In the 1960s, Arno Penzias and Robert Wilson discovered the “cosmic microwave background radiation”
• If you point a radio telescope at the space between stars, you will hear faint interference
• This demonstrated that the Universe was formerly more dense than now, which refutes the steady state hypothesis
In basic terms, what does the Big Bang theory say?
• The Universe began approximately 13.7 billion years ago
• Space and matter have been expanding and cooling since then
What is the current state of the Big Bang?
• We will never be able to travel back in time to observe the beginning
• Physicists used high-energy collisions to test hypotheses related to the Big Bang
• There is a physical restriction on understanding the first moment of the Big Bang
Are there viable alternatives to the Big Bang?
• Oscillating universe — Universes expand and contract until the right one pops out
• Multiple Universes — Infinite number of Universes exist beyond our ability to observe them
• Inflationary models
• Hawking’s theory
William Lane Craig on Alternatives
Oscillating Model:
• Violates the laws of physics (a beginning singularity is inevitable according to general relativity)
• Not enough density in the universe to contract the universe (pg. 114)
• The universe is actually speeding up in its expansion
• Some estimates say that only 100 universes could have existed before this one (does not resolve the problem for atheists) (pg. 115)
Multiple universes (especially one with an eternal mother universe):
• Cannot explain the beginning of the model (a quantum sea of energy is something, not nothing)
• Eventually, all universes would collide together (pg. 117)
Inflationary models:
• One cyclic model is inconsistent with the string theory that it is based on
• Another chaotic inflation model does not resolve the problem of a beginning (pgs. 116-117)
Hawking’s theory:
• Uses imaginary numbers in the equations to describe the universe
• Essentially an attempt to game the equations to remove the origin of the universe (pg. 120)
