Yahoo! Answers

**Secret Revealed**

Before we could even go to space, the myth was the great wall is visible from the moon. Ever since we got to space, astronauts have been looking for it.

Mathematically, the wall would have to be at least 70 miles (110 km) wide to be seen from the moon with unaided eyes. Since the wall has a maximum width of 30 ft (9.1 m), this is easily dismissed as myth. The moon legend came from a 1754 letter by William Stukeley; his remarks on the massive size of the wall could have been literary hyperbole. But, some people took it literally.

In his defense, there have been a few claims that the great wall can be seen from low earth orbit — as little as 100 miles (160 km). A number of astronauts have claimed they have seen it. Even the European Space Agency claimed it was visible and published a picture. A week later they issued a press release indicating it was actually a river and not the Great Wall of China.

NASA claims it, “generally isn’t [visible], at least to the unaided eye.” Mathematically, it’s the same answer, unless you have 20/3 or better vision. But, according to the Journal of Optometry, “Not even the best of human eyes at a simple glance could see the Great Wall of China from Space.” That’s because the anatomy of the eye limits vision to an acuity no greater than 20/9. So, 20/3 is impossible.

The gaza pyramids on the other hand are about 22 times wider than the Great Wall of China; they are visible from low earth orbit.

Chad Upton is the editor-in-chief of Broken Secrets and an official Yahoo Answers contributor.

Thanks for reading,

Sources: wikipedia (Great Wall of China), Journal of Optometry, NASA

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**Secret Revealed**

Tying shoes together by their laces and throwing them onto overhead lines is known as “shoefiti” (shoe + graffiti). Shoefiti started in the United States and spread throughout the world. There is no single reason why people do this, there are many reasons.

When sneakers are festooned on power lines in rough neighborhoods, the conclusion for their presence is often crime related. Some believe they mark crack houses where you can get your fix or some free shoes via ladder. Others say they are shoes that belong to (or hang in memory of) a murder victim. Some say they are for marking gang turf, but Tucson Arizona police have denied that and flagged the turf marker idea as myth.

They did mention that many shoes are removed each week, since they are unsightly and can cause damage to the lines.

They also said that the volume of shoes increases during the summer break from school. A couple of stories have been told that may support this. One is that of tradition, shoes are thrown on power lines to celebrate the last day of school or graduation. Teenage boys have also been said to do this when they lose their virginity.

Perhaps the oldest story about the origin of shoefiti claims it was tradition for soldiers to hang their boots on the power lines at base when they completed basic training, went home on leave or left the service entirely.

In some movies, it’s the school bully who steals your shoes and throws them onto the lines. There are also stories of kids retiring their own shoes when they get a new pair.

Chances are good that the people who are doing it now have no idea why their predecessors did it.

Some people may think it’s a harmless tradition, but the shoes can disrupt utility services by adding weight to the lines which causes them to sag and potentially touch other lines or trees, which could also result in fire.

If you want to remove shoes from the lines, because you want your kicks back or you just want to clear the eyesore, you should call the utility company to do it — a few Darwin Award candidates have earned their nomination trying to DIY their shoes back.

Chad Upton is the editor-in-chief of Broken Secrets and an official Yahoo Answers contributor.

Thanks for reading,

Sources: About.com, Snopes, Straight Dope, Wikipedia

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**Secret Revealed**

You probably don’t think about it much, but if you did, you’d notice that it often feels like one nostril or the other is always plugged. That’s completely normal for about 70% of adults.

Assuming you’re healthy, your “plugged” nostril actually allows a tiny amount of air through and your other nostril handles the rest. After an average of 2.5 hours, the cycle will shift and use the alternate nostril as the primary source of air. The following scan shows one nasal passage mostly blocked and the other mostly open.

For a long time, Eastern medicine has had theories about the purpose of this cycle and a number of exercises that involve moving air through a specific nostril. On the other hand, Western scientists didn’t come up with a physiological purpose for this phenomena until more recently.

Research indicates that the high/low flow approach in the two nostrils optimizes your sense of smell. As you’ve probably discovered first hand, or shall we say finger, the inside of your nose is lined with mucus. This mucus continues deep inside your nasal passage and is very important; it acts as a barrier and helps protect your brain from infection. But, it also means that something you smell has to be absorbed by the mucus before you can smell it.

This mucus absorbs different chemical compounds at different rates. Therefore, some smells are better detected when they are absorbed in more concentrated levels in the slow moving airstream of your plugged nostril while others are better smelled when absorbed in lower concentration through the fast moving airstream of the other nostril.

Humans have about 1.6 sq inches (10 cm²) of smell receptor cells in our nasal passage. By contrast, dogs have 17 times more space dedicated to these same receptors, and in greater density, which explains why their sense of smell is so much better than ours.

Chad Upton is the editor-in-chief of Broken Secrets and an official Yahoo Answers contributor.

Thanks for reading,

Sources: wikipedia (Nasal Cycle, Olfaction)

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