Scientists have spotted the first hints that Albert Einstein's formulation of gravity operates in the quantum realm.

The hints have to do with observations of a falling quantum object, and though this may not seem like a huge deal (literally, we are talking about atoms here), it could be an important step on the road to a theory of ... everything.

To start, we have to go back to the early years of the 20th century. Consider Einstein's iconic theory of gravity, general relativity, and the elusive realm of quantum mechanics. While the former describes the universe on scales of planets, stars and black holes, even demonstrating how galaxies and galaxy clusters formed, the latter describes the counterintuitive physics found on scales smaller than atoms. But there is a problem: these two important theories don't play well together.