To fight against our global enemy, coronavirus, it helps immensely if we can see what we’re fighting against. But this virus is so tiny, that it can’t be seen with a standard light microscope. To observe the COVID-19 and take its photos, scientists have used electron microscopes. And in this stunning educative video, Vox explains how the photos of the coronavirus are taken and processed.
When it comes to the size, the coronavirus measures around 100 nanometers. For comparison, the smallest wavelengths of light that humans can see measure around 400 nanometers. This is why scientists can’t use a standard light microscope. You know, something like the one most of us used in science classes. Enter electron microscopes. “To see something that small, you need a device that uses smaller wavelengths than light. Electrons, when accelerated in a field, behave as a wave with a tiny wavelength to accomplish this,” Vox explains.
To observe the coronavirus and take its photos, scientists use two electron microscopy techniques: SEM and TEM. SEM (Scanning Electron Microscope) scans the surface of a sample and records information that bounces back. This gives us a realistic photo, with depth and lights and shadows. TEM (Transmission Electron Microscope) uses a different method. It transmits electrons all the way through a sample and projects a cross-section of its inner structure. See the screenshot below:
After the images are taken, they are black and white. They are colorized later for additional clarity. Both TEM and SEM images are important for scientists because together they help them observe the virus and learn how it behaves.
What I particularly like about this video is that it has made something so abstract much easier to understand. Of course, it’s interesting to learn how photos of a tiny virus are made. And needless to say, I hope that the subject of these photographs will be successfully overcome in the nearest future.