The exact number of atoms in the universe is not known with certainty. However, we can make estimates based on our current understanding of the universe.
The observable universe, which is the portion of the universe we can currently observe, is estimated to contain about 10^80 atoms. This estimate takes into account the estimated number of atoms in stars, galaxies, and other observable structures.
It's important to note that the observable universe is just a fraction of the entire universe, as the universe is thought to be much larger and potentially infinite in size. The actual number of atoms in the entire universe, including regions beyond our observable reach, is not known.
Additionally, the concept of the universe extends beyond atoms, including other forms of matter, such as dark matter, and other energy forms.
It's worth mentioning that our understanding of the universe is continually evolving, and as scientific knowledge progresses, our estimates and understanding of its composition may change.