In the observable universe, scientists estimate that there are possibly 10 quadrillion vigintillion and 100,000 quadrillion vigintillion atoms, according to Universe Today. The number of atoms in the universe beyond what is known is not calculable.
The observable universe is estimated to traverse approximately 93 billion light years. Scientists estimate that between 300 and 500 billion galaxies exist within the known universe, or, more precisely, as far as the most distant objects are able to be observed by the expansion of space. Dark energy and dark matter are also unexplored to a great extent, which allow scientists only to make approximations.