When you look around you, what do you see? The world is filled with all sorts of things to look at. Trees, birds, people, cars… the list goes on and on.
If you look up at the night sky, you may see the moon, stars and even distant planets. Some of these objects may be millions of miles away. Isn't it amazing what you can see with your eyes?
Would you believe, though, that there are all sorts of things close by that you can't see? It's true! Things like germs, bacteria… even dust mites… are all around us and invisible to the naked eye.
We call these types of things "microscopic objects" because we need a microscope to see them. Our eyes have limits, so we can't see extremely small objects without help. Certain tools, like magnifying glasses, microscopes and telescopes, magnify objects so we can see them.
"Magnification" means making something appear bigger without actually changing its physical size. Magnifying tools use a special lens (or a combination of lenses) to bend light at an angle to increase the size of the image that is sent to the eye. As the image sent to the eye by way of the lens increases, you see an object more easily, even though its physical size has not changed.
Experts believe that the naked eye — a normal eye with regular vision and unaided by any other tools — can see objects as small as about 0.1 millimeters. To put this in perspective, the tiniest things a human being can usually see with the naked eye are things like human hair (with the naked eye and under a microscope) and lice (with the naked eye and under a microscope).
With the help of powerful microscopes, though, humans are able to see incredibly small things impossible to see with the naked eye. Until recently, standard microscopes would allow you to see things as small as one micrometer, which is equal to 0.001 mm.
A new invention — the "microsphere nanoscope" — combines a standard microscope with a complex device (called a "transparent microsphere") to allow you to see things up to 20 times smaller! Researchers believe this powerful new tool could allow them to see inside human cells and even examine live viruses in detail for the first time ever.
In the future, scientists believe they'll be able to develop this tool to see even smaller things. Many researchers believe there is no theoretical limit on how small an object they'll one day be able to see. Scientists are excited about the research possibilities this new tool will open up in the future.