The "visible" universe

In Big Bang Cosmology, the observable universe consists of the galaxies and other matter that we can in principle observe from Earth in the present day, because light (or other signals) from those objects has had time to reach us since the beginning of the cosmological expansion. The portion of it that we (humans, from the perspective of planet Earth) are able to observe is determined by whether or not the light and other signals originating from distant objects has had time to arrive at our point of observation (planet Earth).
The edge of the observable universe is now located about 46.5 billion light-years away
Estimates of the matter content of the observable universe indicate that it contains on the order of 1080 (10 to the 80Th) atoms. The vast majority of the energy density is contributed by dark matter and dark energy.