SUMMARY
Electromagnetic radiation (EMR) does not currently drive intergalactic space expansion due to its low energy density. In the early universe, EMR had a significant impact on expansion dynamics, but this effect has diminished over time. The discussion clarifies that beam-powered propulsion, which involves radiation pushing against objects, is unrelated to the expansion of the universe. The energy densities of matter, radiation, and dark energy behave differently as the universe expands, with radiation density decreasing as the fourth power of the scale factor.
PREREQUISITES
- Understanding of cosmological concepts such as energy density, scale factor, and expansion dynamics.
- Familiarity with the principles of electromagnetic radiation and its properties.
- Knowledge of the differences between matter, radiation, and dark energy in cosmology.
- Basic grasp of equations related to cosmological models, including the Friedmann equations.
NEXT STEPS
- Study the Friedmann equations to understand the dynamics of cosmic expansion.
- Learn about the Cosmic Microwave Background Radiation (CMBR) and its significance in cosmology.
- Explore the concept of dark energy and its role in the accelerated expansion of the universe.
- Investigate beam-powered propulsion and its applications in modern physics and engineering.
USEFUL FOR
Astronomers, astrophysicists, cosmologists, and students interested in the dynamics of the universe and the role of electromagnetic radiation in cosmic expansion.