[转帖]鲜为人知的八个科学常识误区

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动物能够预知自然灾害 

 说动物拥有神秘的第六感，可以预知自然灾害，这是没有根据的。单是敏锐的嗅觉、听觉以及强烈的本能就足以使它们在飓风或海啸来袭时往山坡上四散逃逸。即便如此，动物们还是常常会在自然灾害中丧生。这样看来，即使它们真的有什么第六感的话，那也并不是什么太了不起的东西。

中国的长城是从太空中用肉眼能看见的唯一人工建筑

这种在民间广为流传的说法有好几个不同版本，但却都是错的。宇航员可以在近地轨道上看见长城，同时还能看见其他很多建筑，比如吉萨的金字塔，甚至还有飞机跑道。不过，从月球上是无法看见长城的。

狗嘴比人嘴干净

狗有舔东西的习惯，回去舔一些无人敢舔的东西。尽管如此，还是经常有人这样吹嘘：从科学的角度来说，狗嘴里的细菌更少。事实是，口腔里的细菌种类千差万别，你只能说它们各不相同，却不能说谁比谁更干净。

人类只利用了自身大脑的十分之一

这一论断深受各类媒体追捧，少说也已经流传了一个世纪。还好，这不是真的。磁共振成像清楚地显示——这些图像竟然还是五颜六色的呢——人类很好地利用了自身大脑皮层的大部分，即使在打瞌睡的时候也是如此。

成年人不会再长新的脑细胞

人类大脑发育的关键时期主要是在儿童时期，但这并不意味着打那以后它就完全走下坡路了。研究表明，进入成年许久以后，人的神经细胞仍然在继续生长和变化。

闪电从来不会两次击中同一个地方

事实上，闪电特别青睐某些特定的地方，尤其是高处。帝国大厦每年会被电击约二十五次。很久以前，本富兰克林就已经认识到了这一点。他在自家屋顶上安了一根金属棒，从上面接了根金属线到地上，有此发明了避雷针。

太空中没有重力

这一普遍误解的产生得归咎于“失重状态”这个词。重力无处不在，即便是在太空中也不例外。宇航员表明上看起来是失重的，那是因为他们在不停地往地球方向做自由落体运动，而他们在水平方向上的运动又使他们保持着漂浮的状态。重力的作用随着距离的增大而减小，但是不可能完全消失。对了，说到这里，太空也不是真空状态的。太空中有各种各样的原子，只不过有时它们彼此相距甚远而已。(即使是这样稀薄的气体也会使空间的总引力增大！)

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鸡汤能治好感冒

说治好有点言过其实了，不过科学研究表明，世界各地的妈妈们喜欢往孩子嘴里灌几勺鸡汤还是挺对的。研究发现，鸡汤里的确含有消炎成分，可以缓解(喉部的)充血症状。

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Animals can predict natural disasters

There is no evidence that animals possess a mysterious sixth-sense allowing them to predict natural disasters. Their keen senses of smell, hearing, and sharp instincts alone are enough to send them scattering for the hillsides during a hurricane or tsunami. And even so, animals often die during natural disasters, so if they do have some sort of sixth sense, it's not worth much.
The Great Wall of China is the only man-made structure visible from space

There are several variations on this folkloric statement, and they're all false. Astronauts can spot the Great Wall from low earth orbit, along with plenty of other things like the Giza pyramids and even airport runways. But they can't see the Wall from the Moon.

A dog's mouth is cleaner than a human's

Despite a habit of licking things no human would dare, Fido's mouth is often touted as scientifically more sterile. Truth is, oral bacteria are so species-specific that one can't be considered cleaner than the other, just different.

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Humans use only 10 percent of their brains

This media darling has been around for at least a century. Fortunately, it's just not true. MRI(magnetic resonance imaging) clearly demonstrates--with fancy colors no less--that humans put most of their cerebral cortex to good use, even while dozing.

Adults don't grow new brain cells

Much of a human's crucial brain development happens during childhood, but it isn't all downhill from there. Studies have shown that neurons continue to grow and change well into the adult years.

Lightning never strikes the same place twice

In fact lightning favors certain spots, particularly high locations. The Empire State Building is struck about 25 times every year. Ben Franklin grasped the concept long ago and mounted a metal rod atop the roof of his home, then ran a wire to the ground, thereby inverting the lightning rod.

There is no gravity in space

Blame the term "zero-gravity" for this common misconception. Gravity is everywhere, even in space. Astronauts look weightless because they are in continuous freefall towards the Earth, staying aloft because of their horizontal motion. The effect of gravity diminishes with distance, but it never truly goes away. Oh, and while we're at it, it's also untrue that space is a vacuum. There are all kinds of atoms out there, albeit sometimes far apart (and this thin gas adds to the collective gravity budget, too!)

Chichen soup can cure the common cold
Cure is a strong word, but science suggests Moms around the world are still right in forcing spoonfuls of chicken soup down their kids' throats. Studies have found that the broth actually contains anti-inflammatory properties that help reduce congestion