The United States uses the most advanced microscope to see viruses in the air?

Recently, a picture of "the air is full of viruses" went viral online. It is said that this was seen by the most advanced microscope in the United States. Is this really the case? Can we still go out? Let's find out.

Text/Reporter Li Li Editor/Liu Zhao

New Media Editor/Chen Xuanzhi

Rumor-busting experts:

Ye Sheng (Professor and doctoral supervisor at Beihang University, distinguished researcher at Beihang University's Big Data Precision Medicine High-tech Innovation Center, and secretary-general of the Science Popularization Committee of the Chinese Biophysical Society)

gossip:

A picture of "the most advanced microscope in the United States to see the virus in the air" went viral on WeChat Moments and the Internet. A threatening sentence was written right above the picture: "Do you still dare to go out?" If you look carefully at the "golden position" in the middle of the photo, you will find that this commercial district with overpasses and high-rise buildings is occupied by viruses everywhere, from the ground to the sky. In particular, the ground of the district is almost completely surrounded by viruses.

the truth:

Any microscope cannot directly see things in the "air". Microscopes can only see prepared samples. Although magnifying glasses and telescopes can directly see things in the "air", they are far from the nanoscale of viruses, and even cells cannot be seen. The scale of this picture is completely wrong. It is a composite picture. Apart from conveying the information that the person who composed the picture wants to convey, it has no practical value.

First of all, theoretically speaking, no microscope can directly see things "in the air"; a microscope can only view prepared samples.

Microscopes can be classified into optical microscopes and electron microscopes according to the microscopic principles. The two have different magnification factors. Optical microscopes can generally magnify up to 2000 times, while electron microscopes can magnify up to hundreds of thousands times.

Traditional light microscopes can only observe subcellular structures, that is, at the submicron scale. Modern light microscopes can further improve the resolution, but it is still not enough to see viruses. Viruses are too small, with a scale of only tens to hundreds of nanometers, which is usually smaller than the wavelength of visible light. Therefore, they cannot be seen under a light microscope and must be observed with an electron microscope.

Electron microscopes can not only see viruses and their internal structures, but can even see the specific three-dimensional structure of protein molecules. However, electron microscopes are huge devices, and the sample chambers they observe often need to be evacuated, which means that electron microscopes cannot be used to see things "in the air" in principle. Magnifying glasses and telescopes can directly see things "in the air", but they are far from the nanoscale of viruses, and they cannot even see cells.

▲Color photos of the new coronavirus previously published by The Lancet

Secondly, the virus does not float directly in the air. For example, the new coronavirus needs to attach to droplets to enter the air. Most droplets settle quickly and are basically on the ground. The droplets that can float in the air are very small particles, micron-level droplets, which can be called aerosols. These aerosols with viruses that can float in the air cannot reach a very high density in open spaces, so they do not pose a risk of infection.

Most importantly, the scale of this picture is completely wrong! Viruses are at the nanometer level, while street buildings are at the meter level, which is a billion times different. So if you really draw the virus and the street together, they won’t even occupy a single pixel. Therefore, such an obviously synthesized picture has no practical value except for conveying the information that the synthesizer wants to convey.

▲A virus is definitely not a bacteria. It is much smaller than bacteria.

At present, there are about 5,000 viruses that have been observed, classified, named, and scientifically described by humans. It sounds like a lot, but in fact, according to scientists' estimates, the total number of all viruses in the world may reach more than 1 million, and we only know a small part of them.

The reason why there are more than 1 million kinds of viruses is that almost all cell life can be infected by some virus. In fact, viruses must rely on cells to continue their "life" and replicate more viruses. If there were only viruses in the world, they would not be able to "survive" at all. ■

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