Then we decide which is bigger. Our travels inside take us to the vanishingly small. Those outside reach to immense spaces of an expanding Universe. We start small. That's 1 preceded by 9 zeros and a decimal point.
Few people can visualize an atom.
The Theory of Superstrings holds that quarks are tiny strings with a characteristic length of 10 to the minus 35 meters. We know no smaller particle than the quark. Now let's go outside the atom and to the stars. That's 1 followed by 11 zeros. Much is left to discover, however, both Inside and Outside the Atom.