What are the open and closed big bang theories of the universe, the inflationary model, and difference between them?
Open vs. Closed: The difference is what happens later.
Inflationary Model: How things got started.
The open big bang theory states that the universe began in a big bang and will continue expanding forever.
The closed big bang theory states that the universe began in a big bang, but gravity will eventually overcome the inertia and contract, ending in a big crunch.
The Inflationary Model states that the universe expanded rapidly and exponentially shortly after the big bang and then slowed down.