Thermodynamics of Shearing Massless Scalar Field Spacetimes is Inconsistent With the Weyl Curvature Hypothesis

Understand

Our Universe has an arrow of time.

• In accordance with the second law of thermodynamics, entropy has been increasing ever since the Big Bang.
• The fact that matter is in thermal equilibrium in the very early Universe, as indicated by the cosmic microwave background, has led to the idea that gravitational entropy must be very low in the beginning.
• Penrose proposed that gravitational entropy can be quantified by the Weyl curvature, which increases as structures formed.