What is the estimated number of galaxies in the observable universe, and what factors contribute to the uncertainty in this estimation?

The observable universe is about 93 billion light-years in diameter

The observable universe spans approximately 93 billion light-years across

Pi has been calculated to over 100 trillion digits — but 39 digits is enough to measure the observable universe to the width of a hydrogen atom

Pi's 39-digit approximation measures universe's width to hydrogen atom's size

There are more possible chess games than atoms in the observable universe — about 10^120 vs 10^80

Chess games exceed the observable universe's atom count: 10^120 > 10^80

There are more stars in the universe than grains of sand on all of Earth's beaches

Stars vastly outnumber Earth's sand grains

What the cosmological constant problem is — quantum field theory predicts vacuum energy 10^120 times too large

Quantum field theory overestimates vacuum energy by 10^120 times, causing the cosmological constant problem

What the CMB power spectrum tells us — the age, composition, and geometry of the universe

CMB power spectrum reveals universe's age, composition, and large-scale structure