Question

The Planck era refers to the time period

A) before the Big Bang.
B) before the Planck time.
C) after the Planck time.
D) after inflation.
E) after the GUT era

Answer 1

The Planck era refers to the time period before the Planck time, which is the earliest period in the history of the universe. Inflation occurred after the Planck time, when the universe was between 10^-35 and 10^-33 second old. Therefore, the correct option is b.

Step-by-step explanation:

The Planck era refers to the time period before the Planck time. The Planck time is the earliest period in the history of the universe, from time zero to 10^-43 second, where the universe was unimaginably hot and dense, and quantum effects of gravity dominated physical interactions. Inflation, on the other hand, is hypothesized to have occurred after the Planck time, when the universe was between perhaps 10^-35 and 10^-33 second old, and the temperature was 10^27 to 10^28 K. During this rapid expansion, the three forces (electromagnetic, strong, and weak) were thought to have been unified, and this is when GUTs (Grand Unified Theories) are applicable.