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Showing posts with the label scanning electron microscope

SARS-CoV-2: The New Normal

SARS-CoV-2 is the name of the pandemic virus first identified in Wuhan, China in December 2019.  Why that name?  Because it looked genetically similar to the virus that caused the 2003 SARS outbreak.  You've regularly seen the COVID-19 virus as a sphere with what looks like golf tees sticking out of the surface.  First, this virus is so small that you can't see it using an ordinary microscope. Bacteria are between 0.2 and 2 micrometers, so you can't even see this in a compound light microscope. Viruses are not measured in micrometers, but nanometers, which is one-thousandth a micrometer.  The coronavirus is just 50 nanometers across, or 0.05 micrometers. But visible light ranges from 300 to 700 nanometer, so light photons are too large to distinguish something so small as 50 nm. You thus turn to an electron microscope, invented in 1930, but improved to what is now called a Scanning Electron Microscope, or SEM.   Yes, instead of photons, something so small as an electron mus