The Arrow of Time feat. Sean Carroll

What is a common observation that distinguishes the past from the future?

• Objects always move forward in space.

• We can remember past events but not future events.

• Gravity only pulls things down, not up.

• Light always travels at a constant speed.

How do the fundamental laws of physics generally describe the relationship between the past and the future?

• They explicitly define a direction for time.

• They show that the future is inherently more complex than the past.

• They do not distinguish intrinsically between the past and the future.

• They predict that time will eventually reverse its direction.

Which physical concept describes the natural tendency of systems to move from an ordered state to a more disordered state over time?

• Momentum

• Energy conservation

• Entropy

• Relativity

What is a significant question cosmologists are trying to answer regarding the early universe and the arrow of time?

• Why the universe is expanding at an accelerating rate.

• Why the early universe had such a low-entropy state.

• How black holes form and evolve.

• The exact composition of dark matter and dark energy.