There’s a very special atom in this photograph, and it’s visible to the naked eye.
No, really – it’s a single positively-charged strontium atom rendered motionless by electric fields. You can see it, right there in the center, as a very tiny dot between two metal electrodes, their small needle tips only two millimeters apart.
Here’s a zoomed-in version for a better look:
“When illuminated by a laser of the right blue-violet colour, the atom absorbs and re-emits light particles sufficiently quickly for an ordinary camera to capture it in a long exposure photograph.”
The photo, taken by David Nadlinger from the University of Oxford, is titled “Single Atom In An Ion Trap.” It won this year’s Engineering and Physical Sciences Research Council science photography competition, beating out over 100 other entries in categories ranging from “Eureka & Discovery” to “Weird & Wonderful.” This one happened to compete in the “Equipment & Facilities” category.
“The idea of being able to see a single atom with the naked eye had struck me as a wonderfully direct and visceral bridge between the miniscule quantum world and our macroscopic reality,” Nadlinger said, explaining how he devised the winning photo. “A back-of-the-envelope calculation showed the numbers to be on my side, and when I set off to the lab with camera and tripods one quiet Sunday afternoon, I was rewarded with this particular picture of a small, pale blue dot.”
Nadlinger’s description of the visible atom as a “small, pale blue dot” is likely a reference to the famous Pale Blue Dot photo of Earth taken by the Voyager 1 space probe in 1990. Voyager 1 was about 6 billion kilometers (3.7 billion miles) away at the time, causing our planet to appear very tiny, indeed. About the same size as that strontium atom, in fact.
To find out more about this photo and view the other winners, head over to the official EPSRC website.