Approximately how long ago did the event marking the start of the universe, the Big Bang, occur?
Answer
Roughly 13.8 billion years ago
The standard cosmological model estimates the Big Bang, which initiated the expansion of space and time, took place approximately 13.8 billion years in the past.

#Videos
What Was Here Before the Solar System? - YouTube
Related Questions
Approximately how long ago did the event marking the start of the universe, the Big Bang, occur?What is the distinguishing feature of the Planck Epoch immediately following the Big Bang?At what approximate temperature did the universe cool sufficiently for protons and electrons to combine and form the first stable, neutral atoms?What critical change resulted from the formation of stable, neutral atoms during recombination?What physical phenomenon does the Cosmic Microwave Background (CMB) radiation represent?Which epoch is defined as stretching from the end of the radiation-dominated era (recombination) until the first stars ionized the gas?If one could observe the universe during the Dark Ages, what would be present besides the faint CMB warmth?What distinctive characteristic defined the material composition of the very first stars, known as Population III stars?How did the theoretical mass of Population III stars generally compare to our Sun, a Population I star?In the hierarchical assembly process of cosmic structures, which components formed prior to large, complex galaxies?According to theoretical models addressing the boundary condition of time, which concept describes our Big Bang as one nucleation event within a larger meta-verse?