What Actually Happened During the Big Bang? | The Sleepy Scientist

🎧 Prefer listening with the screen off? The Sleepy Scientist is also on Spotify: https://open.spotify.com/show/0340wK7... The Big Bang is usually pictured as a colossal explosion erupting from one point into empty space, but that familiar image gets some of the most important physics wrong. In this slow, relaxing journey through cosmology, we explore what scientists actually mean by an expanding Universe, why there is no known centre of the expansion, how distant galaxies can recede faster than light without breaking relativity, and why the Big Bang happened everywhere rather than at one special location. We’ll follow the Universe backwards towards its hotter and denser past, through cosmic inflation, the formation of the first particles and light elements, and the release of the cosmic microwave background, before looking at the enormous questions that remain unanswered about the earliest moments of cosmic history. SOURCES: NASA Science — The Big Bang https://science.nasa.gov/universe/the... NASA Science — Webb Telescope & The Big Bang https://science.nasa.gov/mission/webb... NASA Science — Big Bang and the Evolution of the Universe https://science.nasa.gov/astrophysics... NASA Science — Edwin Hubble and the Expanding Universe https://science.nasa.gov/missions/hub... NASA Science — Universe Overview and Big Bang Nucleosynthesis https://science.nasa.gov/universe/ove... European Space Agency — Planck and the Cosmic Microwave Background https://www.esa.int/Science_Explorati... NASA Science — Measuring the Big Bang with the Cosmic Background Explorer https://science.nasa.gov/missions/exp... Nobel Prize — Arno Penzias and Robert Wilson’s Discovery of the Cosmic Microwave Background https://www.nobelprize.org/prizes/phy... University of Cambridge — The Fred Hoyle Collection https://www.english.cam.ac.uk/cmt/?p=... Particle Data Group — Big Bang Nucleosynthesis https://pdg.lbl.gov/2025/reviews/rpp2...