Quantum gravity

Definition

Quantum gravity is a theoretical framework that seeks to describe the gravitational force according to the principles of quantum mechanics. It aims to unify general relativity, which describes gravity at large scales, with quantum mechanics, which governs subatomic particles.

5 Must Know Facts For Your Next Test

1. Quantum gravity attempts to reconcile the apparent incompatibility between general relativity and quantum mechanics.
2. One of the key approaches to quantum gravity is string theory, which posits that particles are one-dimensional strings rather than point-like objects.
3. Another approach is loop quantum gravity, which suggests that space-time has a discrete structure at the smallest scales.
4. A major challenge in quantum gravity is formulating a theory that produces testable predictions.
5. The Planck scale is critical in quantum gravity; it represents the energy scale at which quantum effects of gravity become significant.

Review Questions

• What are the main goals of a theory of quantum gravity?
• How does loop quantum gravity differ from string theory?
• Why is the Planck scale important in studies of quantum gravity?

Related terms

General Relativity: A theory of gravitation developed by Albert Einstein, describing gravity as a curvature of space-time caused by mass and energy.

Quantum Mechanics:

A fundamental theory in physics describing physical properties at small scales, primarily at the level of atoms and subatomic particles.

Planck Scale:

The energy scale around $10^{19}$ GeV where gravitational effects are expected to become comparable in strength to other fundamental forces.