In the 17th Century, a Dutch merchant named Antony van Leeuwenhoek began experimenting with making new microscope lenses and, in the process, plunged humanity into a new world—this one teeming with previously-undiscovered life, from small bacteria to single-celled algae and more.

More than 400 years later, scientists are in the midst of an equally-important revolution. They’re diving into a previously-hidden realm—far wilder than anything van Leeuwenhoek, known as the “father of microbiology,” could have imagined. Some researchers, like physicists Margaret Murnane and Henry Kapteyn, are exploring this world of even tinier things with microscopes that are many times more precise than the Dutch scientist’s. Others, like Jun Ye, are using lasers to cool clouds of atoms to just a millionth of a degree above absolute zero with the goal of collecting better measurements of natural phenomena.