Earlier this month, a short video went viral on social media. The video shooter pointed the camera of his mobile phone at a strange metal can, and after removing the white lid on the can, the video showed obvious blur and a lot of white noise. As if feeling that it was not enjoyable enough, the photographer tried to cover the jar with his hand, and the noise disappeared immediately after removing the hand, and the noise appeared again.
Some of the comments started to make the video creepy. They said that the jar in the video is a lead jar, which is used to transport or store radioactive substances, and the noise in the picture is a sign that the lens is being irradiated. They then worried about the health of the author of the video: if they dared to be exposed to radiation, they might have already stepped into the coffin with one foot. Other netizens tried their best to find loopholes in the video in a scientific spirit of doubting everything.
The original author of the video was a Twitter user named Rye Pony, who actually uploaded two videos on November 3rd. In the follow-up video, Pony took out a Geiger counter specially used to detect radiation, and accidentally dropped the counter on the table. He picked up the counter again and pointed it at the inside of the mysterious jar. The counter immediately issued a beeping alarm sound, the sound became more rapid, and the numbers on the screen continued to climb as if there was really deadly radiation.
Half an hour after the video was uploaded, Pony sent a reply, hammering himself,
These are all fake.
The first video is edited. As far as today's video editing software is concerned, the blur and noise caused by fake radiation do not require too much technical content, just add a mask or mask. The act of covering the jar with hands is even more pretentious. Most radioactive materials produce gamma rays that are so penetrating that they cannot be blocked by human flesh. Assuming that Pony is really photographing highly radioactive substances, even if he reaches out to cover the cover, the noise in the picture will not disappear so obviously.
In the second video, Pony deliberately uses a technique that is close to magic: pretending to be slippery, throwing away the Geiger counter, distracting the audience, and taking the opportunity to place a small piece of pitchblende prepared in advance next to the tank mine.
Uranium ore is radioactive, but the radiation intensity of a small piece of ore is not as high as he imagined. He had to stick the ore tightly to the Geiger tube on the Geiger counter to make the counter sound an alarm. In the video, the maximum number the counter gets is 35.62µSv/h, or 35.62 microsieverts of ionizing radiation per hour.
The so-called ionization in ionizing radiation means that the corresponding rays or particles have sufficient energy to impact the electrons in molecules or atoms and make them break away from the original medium. Regardless of whether the medium is mechanical parts or human cells, it will lose its original properties and functions after being exposed to excessive radiation.
As for the Sievert, it is a unit of measurement to measure the impact of ionizing radiation on the human body. 1 Sv is equal to 1000 millisieverts (mSv) and 1 millisievert is equal to 1000 microsieverts (µSv). We often say that talking about toxicity regardless of the dose is playing hooligans, and the same is true for ionizing radiation. Ionizing radiation exists in everything that humans can come into contact with. Any ordinary person living on the earth has to bear 2.4 mSv (0.27µSv / h) of radiation every year.
At present, it has been confirmed that a radiation dose of 100mSv (100000µSv) will cause obvious harm to human health. Because the human body has the ability to repair, as long as it is not exposed to radiation for a long time or directly, a healthy adult can withstand radiation in millisieverts. For reference, a chest X-ray examination will bring about 7mSv of radiation; a whole body CT examination has a radiation dose of about 10-20mSv. In contrast, the radiation from that piece of uranium ore is far from fatal, and this does not take into account the attenuation of radiation after physical distance. As long as Pony isn't stupid enough to wear uranium ore as a necklace around his chest 24 hours a day, or take it out from time to time like an old man's plate of walnuts, we don't have to worry about when he will die.
On the Chinese Internet, this kind of behavior that intentionally creates controversy, gimmicks, or risks to attract traffic is generally called phishing. Pony did not explain the motivation for uploading these two videos. Although he himself refuted the rumors quite quickly, he has been unable to prevent this video from spreading around the world for countless video porters to continue fishing.
Before Pony, there have been similar cases on the Internet that exploited the knowledge blind spots of netizens to cheat replies, and there was more than one case. In October, for example, a user on Reddit posted this phishing thread: Can anyone tell me why can't i take a decent picture with this Cinnamon stick? The periphery of the stick is full of white spots, very similar to the noise caused by radiation impacting the lens.
There is a large string of English words engraved on the stick, such as dangerous, radioactive, drop it and run (Drop & Run), and the words cobalt-60 (Co 60). Cobalt-60 is a man-made radioactive isotope with extremely strong radiation properties and is generally used for cancer radiotherapy, sterilization, or deworming. There is another line below it that says 3540 Curie. Curie (Curie, Ci) originated from the famous scientist Marie Curie and is another unit to measure the radioactive strength of substances. If these contents are true, when you see and see these words clearly with your own eyes (assuming you are less than 1 meter away from this stick), the radiation level you have suffered has exceeded 40Sv per hour, drop it and run. At least it can guarantee that you can survive today.
If you don't have any protective measures on your body, but you insist on stuffing it in your pants pocket, you can live for at most 15 minutes.
After knowing the power of cobalt-60 and then looking at the original post, you can see doubts everywhere it is impossible for ordinary people to easily come into contact with a whole unshielded cobalt-60, and it is even more impossible for them to have such a leisurely time to take out their mobile phones take a photo. Type the warning slogan "Drop & Run" into Google's search bar and we were able to find the following two results. The first is the stick’s true self a cobalt-60 rod sample sealed at the Los Alamos Laboratory in the United States, with the exact same words engraved on it.
The second is where the original photo actually came from a website where users upload 3D printable models. Some good people made a model of the cobalt rod sample and took several seller shows. The author of the original post randomly picked a photo, and white spots were added to the P. Tuck this model stick into your trouser pocket, and after 15 minutes your pants will only feel a little heavy.
Even without checking it from a journalist's point of view, there is no blurring in the picture itself, and the countless white spots are even more fake. Camera equipment such as smartphones or digital cameras realizes imaging by converting optical signals into electrical signals. At this time, once strong ionizing radiation bombards the lens and the sensor in the device, the electrons that are driven out generate redundant electrical signals, forming the flickering noise we see. Unlike visible light, the gamma rays released by cobalt-60 cannot be captured and reflected by the mirror, which will impact the entire sensor. In reality, radiation noise should spread throughout the entire photo, the entire frame, not just around the source of the radiation.
In such phishing posts, none of the authors really took their own lives as a joke, as the comments said, I don't know the radiation in the middle of radiation. They knew exactly what they were doing, and even if they showed a real source of radiation that would set off a Geiger counter, short exposure to such radiation would not have killed them at all.
As mentioned earlier, the influence of this phishing content spreads all over the world, including Russia naturally. Putting it in other places, netizens will at most scold after discovering the essence of the post; but in Russia, where there are many ruthless people, there will always be a fearless guy who puts himself into practice for a joke that cannot stand scrutiny. In Russia's Peekaboo forum, there is a ruthless guy with the screen name "Snater". On November 5th, he specially uploaded a video as an official reply to Pony's fishing video.
According to Snett's reply to the post, he is in charge of a geophysical detector, a machine that can detect the depth and thickness of rock and coal seams by emitting gamma rays. The source of the gamma rays is a small piece of cesium-137, and what Snyter does in the video is disassemble the machine, remove the cesium-137 inside, and put it in front of the phone lens.
This piece of cesium-137 emits 0.2mSv/h of radiation, and just holding it in your hand for a few minutes will do no harm. Although the radiation level is much higher than that of Pony's uranium ore, Snett's video picture has almost no visible noise to the naked eye. If Snart did not lie and falsify, his video is the hardest and most convincing counter-evidence.
However, just refuting rumors cannot completely solve the doubts shared by people. We now know that ionizing radiation does cause noise in images from camera equipment. However, at what dose of radiation does noise appear? Furthermore, can we use these noises to use the smartphone that everyone is using as an instrument for detecting radiation intensity?
Neither question is easy to answer. Given that the sensor sensitivity of different camera devices varies greatly (you may get different results with different brands of mobile phones), it is difficult for us to find an exact value that will definitely make the picture start to produce noise. Ionizing radiation is also divided into three, six, and nine grades, each with different energy and penetrating power, and the accuracy of measurement will also be affected by this.
For example, alpha particles cause no less harm than other radiations, but their penetrating power is weak, and they will be covered by equipment casings, lenses, and even human skin. Generally, they do not pose a danger outside the human body, and it is difficult to let the radiation inside the equipment Photosensitive devices produce noise, which can only be detected with professional equipment such as Geiger counters. X-rays commonly used in the medical field and gamma rays with strong penetrating power are prone to noise because CCD and CMOS sensors widely used in imaging equipment are relatively sensitive to these two types of rays.
Picture noise is clearly not an ideal means of quantifying radiation. However, it is the sensitivity of CMOS sensors to radioactive rays that makes it possible to detect radiation with mobile phones. Around 2011, several mobile apps that claim to detect radiation through CMOS sensors appeared on the market, such as WikiSensor on the Apple platform, RadioactivityCounter, and GammaPix which can be used on both Android and Apple. When using these apps, the opaque black tape needs to be pasted on the camera to block the interference of visible light and only let the rays that need to be detected enter the sensor.
The accuracy of the data obtained by these apps is completely incomparable with professional equipment, but a large number of studies in the scientific community are willing to stand for them. A report published on the website of the journal Nature in June 2021 puts it this way: Using sensors built into smartphone cameras to detect radiation has applicability enough to detect radiation before it reaches dangerous levels exist.
The research in the report specially used an old iPhone 6s, installed RadioactivityCounter, and used a cesium-137 gamma ray emitter as a control experiment. According to the experimental records, at a radiation dose higher than 100µSv/h, the error rate of App data is only 1.44%; and at a low dose of about 1.25µSv/h, the error rate rises to 79.16%. Considering that different CMOS sensors have different sensitivities, newer phones with more advanced sensors are more sensitive and will have more interference.
While smartphones are prone to errors at low levels of radiation, they can definitely come in handy when you do have a radioactive spill. With the application of nuclear energy and the popularization of radiation in medical and industrial fields, people have more and more opportunities to be exposed to ionizing radiation. Compared with professional equipment such as Geiger counters, smartphones with CMOS cameras are more popular and inexpensive. The mobile phone itself also has its own data processing capabilities and battery life. It is easy to operate and easy to access, so it has the potential to become a portable radiation monitoring device.
Presumably, in time, any ordinary person will be able to monitor and quantify radiation. Of course, we all hope that we will never have to use this knowledge and radiation detection apps in our lives, but by then, there will probably be fewer misleading phishing posts on the Internet.