[1] It also highlights some lesser known theorists including Georges Lemaître, who first theorised that there was a big bang, Ralph Alpher, who stated that the light from this should be detectable, and Cecilia Payne, who calculated that hydrogen and helium were the dominant elements in the universe.
[2] The episode concludes at the Large Hadron Collider, where physicists create matter in a similar manner to the Big Bang.
[3] Al-Khalili indicates that the difficulty in understanding this is our limited ability to comprehend something of such immensity both physically and philosophically.
[3] Jack Seale, writing for The Guardian, commends the Al-Khalili for, "his usual mix of spectacular locations, clear explanations, a few gags and the stories of scientists who made crucial breakthroughs.
"[2] Gary Rose, writing for RadioTimes however points out that while Al-Khalili is "as watchable as ever", this series, unlike his earlier series Atom, covers well-trodden ground and while there are "oodles of graphs and stats," which he explains, "with seemingly effortless lucidity," regular viewers of Horizon, "might be immune to the barrage of cosmic stats.