And yet, there it is, a strontium atom, like a little round dot, shining clear as day. Nadlinger’s image shows a single atom of strontium, positively charged, held in place in a vacuum by the electromagnetic field produced by two metal electrodes a mere two millimetres apart. In this case, a laser is shone on the strontium atom, and as it absorbs and emits energy, we can see the glow, without actually seeing the atom itself. This image, curiously, shows the strontium atom as a rough circle in two dimensions, as if it were a sphere in real life. In 2008, American physicists used an electron microscope to capture an image of a single hydrogen atom, the smallest and lightest atom of all.

Source: National Post February 14, 2018 18:33 UTC