The quantum revolution never truly ended. Beneath the world of classical physics, at the smallest scales, tiny particles don’t follow the usual rules. Particles sometimes act like waves, and vice versa. Sometimes they seem to exist in two places at once. And sometimes you can’t even know where they are.

For some physicists, like Niels Bohr and his followers, the debates surrounding quantum mechanics were more or less settled by the 1930s. They believed the quantum world could be understood according to probabilities—when you examine a particle, there’s a chance it does one thing and a chance it does another. But other factions, led by Albert Einstein, were never fully satisfied by the explanations of the quantum world, and new theories to explain the atomic realm began to crop up.

Now, nearly a century later, a growing number of physicists are no longer content with the textbook version of quantum physics, which originated from Bohr’s and others’ interpretation of quantum theory, often referred to as the Copenhagen interpretation. The idea is similar to flipping a coin, but before you look at the result, the coin can be thought of as both heads and tails—the act of looking, or measuring, forces the coin to “collapse” into one state or the other. But a new generation of researchers are rethinking why measurements would cause a collapse in the first place.

A new experiment, known as the TEQ collaboration, could help reveal a boundary between the weird quantum world and the normal classical world of billiard balls and projectiles. The TEQ (Testing the large-scale limit of quantum mechanics) researchers are working to construct a device in the next year that would levitate a bit of silicon dioxide, or quartz, measuring nanometers in size—still microscopic, but much larger than the individual particles that scientists have used to demonstrate quantum mechanics previously. How big can an object be and still exhibit quantum behaviors? A baseball won’t behave like an electron—we could never see a ball fly into left field and right field at the same time—but what about a nanoscale piece of quartz?

The experiment is similar to the decades-old search for dark matter particles: physicists haven’t detected them directly yet, but they now know more than before about how massive the particles can’t be. One difference, though, is that physicists know dark matter’s out there, even if they don’t know exactly what it is, says Andrew Geraci, a physicist at Northwestern University. The quantum collapse models that Carlesso and others study aren’t guaranteed to be an accurate representation of what happens to matter on the atomic scale.

Read more at Smithsonian Magazine.

Image: The TEQ experiments will attempt to induce a quantum collapse with a small piece of silicon dioxide, or quartz, measuring nanometers across—tiny, but much larger than individual particles. (University College London)