it is my contention that we can travel the same relative distance in opposite directions. as far as we can reach in space I believe we can also reach the same depths microscopically. if it takes some 50 million light-years from Earth to reach The Sombrero Galaxy what would be a good constant value to measure/compare the distance traveled to reach the nuclei? we say we have detected the earliest traces of the universe, is that comparable to finding the quark or can we go further than the quark?
kemah carles washington

We've had a much easier time with small scales, in part because going the other direction just takes so much time. Voyager 1 has been going for 30 years, and has only gone 100 times the radius of Earth's orbit, less than 0.04 % of the distance to the nearest star (and it's not even heading toward any nearby stars). Meanwhile, we're constructing nanoscale structures in mass quantities, gaining more control over the results all the time, moving individual atoms around to spell things, and probing subatomic structures, with fairly good reason to think that we're looking at the smallest components of matter.

If you settle for what we can observe rather than what we can "touch", we can see much, much farther...unless we're very wrong about the cosmic microwave background, we can "see" pretty much as far as there is to see, though our vision is very limited at that distance.

Also, both have grown in leaps and bounds as various techniques (X-ray crystallography, electron microscopy, scanning-tunneling microscopy, radio astronomy, adaptive optics, orbital telescopes) are developed, rather than in a continuous progression. It could be interesting to compare the landmarks for each extreme of the scale on a single timeline, but I doubt you'll see any consistent relationship.

Quarks and other sub-nucleonic particles can't be seen... only inferred. So we can't really go much further.

Plus, once you get about down to the Planck Length, there is no smaller thing possible. Theory suggests that the "foundation particle" (whatever that may be) must be 1 Planck length or larger.