Start of it all, perhaps

• Book one group including bass for a stellar opening?
• G Boycott breaks 24 - an astronomical event?
• Cosmic explosion
• Theory of the universe, or a hint to the starts of 17-Across and 7-, 10-, 35- and 40-Down
• Origin of the universe, perhaps
• Origin of all that's heard on 5th Nov?
• Universe starter, some say
• Universal theory

Wikipedia Word definitions in Wikipedia
Bigbang is a Norwegian rock band led by frontman Øystein Greni . Over several years the band lineup has altered several times while remaining a trio , with Greni remaining the one constant member. Though the band name spelling is inconsistent, it is usually ...