There is a lot of knowledge out there that is misinterpreted and passed off as the real deal. Sometimes these misconceptions gain new life on the Internet. Here are a few of those misconceptions debunked. 

The Great Wall of China is the Only Man-Made Object Visible from Space

This depends on what we define “space”. If we define “space” as in a low orbit taken by the Space Shuttle (which would be roughly 160 to 350 miles above Earth), then the Great Wall would be almost invisible from that height according to Shuttle astronaut Jay Apt (although man-made items such as airport runways, highways, bridges, dams and the Kennedy Space Center itself are visible). There is another claim that the Great Wall is visible from the Moon. This would be impossible considering it’s even further away from Earth (237,000 miles to be exact). According to Apollo 12 astronaut Alan Bean, the only objects visible from the moon are mostly clouds, oceans, deserts and the occasional green vegetation. To see the Great Wall from the Moon is equivalent to seeking a human hair from 1.5 miles away.

It is believed that the origin of this belief came from Henry Norman’s 1904 book “The People and Politics of the Far East”. However, it was adventurer-lecturer Richard Halliburton’s 1938 travel book “The Orient”, the second installment of his “Book of Wonders” series that helped spread the belief to a wider audience.

Humans Only Use 10 Percent of their Brain

This comes from the claim that humans have unused potential within themselves. Not only is this claim pushed by psychics and other woo-enablers to shill their products but also by the media as well. For example, a 1998 magazine ad campaign for U.S. Satellite Broadcasting used this claim as its marketing angle. That same year, a now-forgotten ABC sitcom “The Secret Lives of Men” also used this claim to promote itself.

Of course this claim is false. Although a small part of brain is used for minor functions at a single given moment, a complex set of activities will require many parts of the brain. In a single day, almost all of the brain has been used. However, the claim specifically states that all brain activity is restricted to only one area of the brain. Brain imaging techniques such as the PET and MRI scans show clear activity throughout the brain. Plus, the brain isn’t an appendix where you can simply remove the “useless” parts.

Chewing Gum Will Remain In Your Digestive Tract for Seven Years If You Swallow It

Rodger Liddle, a gastroenterologist at Duke University School of Medicine, says that nothing will reside in your stomach for that long unless it was stuck there or it was trapped in the intestine. The chewing gum will go through the digestive process at a much slower rate due to its shape and build-up.  Aside from such components such as the sweetener, the chewing gum will remain pretty much intact throughout the duration of the digestion.

Although the gum will pass through your stomach doesn’t mean it’s safe to swallow your gum on a regular basis. Pediatric gastroenterologist David Milov of the Nemour Children’s Clinic in Orlando, Fla wrote in the “Pediatrics” journal back in 1998 that chronic gum swallowing might cause problems in children. For example, he describes a case in which three children suffered gastrointestinal blockages from swallowing too much gum which led to constipation. The “gum ball” had to be extracted from the children’s stomach.

Blood is Actually Blue but it Becomes Red When Exposed to Oxygen

Blood is actually dark red but when it’s exposed to oxygen, it turns bright red. The reason for this is due to its hemoglobin, which is a protein that binds with oxygen to distribute blood throughout the body. Although the veins in your body appear to be blue, the reason for this is because of the way light diffuses on the skin. Veins appear blue because of subcutaneous fat absorbs low-frequency light. The skin only allows high frequency blue and violet wavelengths to reach the veins while pigmentation of the skins absorbs the rest. A similar process in people who are choking as their lips and fingertips turn purple due to the fact that blood turns into an extremely dark shade of red when deprived of oxygen.