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.

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

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Dermatoplyphes or “fingerprints” are common among higher primates, but are present in only some other mammals.

Take whales for example. They’re mammals and they don’t have fingers (although the bones inside their flippers looks like fingers on an x-ray) but the pattern on the underside of their tail is still unique like a fingerprint.

Koala’s on the other hand do have fingers and they do have fingerprints. Koala fingerprints are so similar to human prints that even under an electron microscope they’re nearly indistinguishable from each other.

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

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Sources: naturalscience.com, whalewatchmaui.com

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**Secrets Revealed**

Trick or treating can be traced back to European “guising” traditions where children would travel from home to home, reciting songs, jokes or poems. They didn’t say “trick or treat” back then, it was “please help the guisers” — a reference to the groups who performed plays to ward off evil spirits during Samhain, the Celtic celebration we now know as Halloween.

The children were often given fruit, nuts, sweets or even money. Trick or treating started to take hold in North America during the middle of the 19th century, although it was put on hold for sugar rationing during World War II.

The Celts believed spirits of the dead would walk the earth on Halloween. Costumes were worn to help blend in with and hide from the real spirits who were thought to be walking among them.

The traditional colors of Halloween, Black and orange, have meaning too. Black is the typical color of death in many cultures and orange symbolizes strength in Celtic legend, which was important for weathering a harsh winter. They burned large bonfires, believing this would bring the heat of the sun back after winter. Animal bones were often thrown into the fires and some believe these “bone fires” spawned the term bonfire.

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

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Sources: History.com, IrishCentral.com, Answers.com,

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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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