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OK here is the deal with the space shuttle. It has three rocket engines in the back, but there's absolutely no room inside for all the fuel it needs to launch itself up into space. All of that fuel is stored outside the shuttle, in the big brown cylinder, called the external tank.

The tank containing all the rocket fuel weighs seven times more than the space shuttle itself! That's a lot of really heavy fuel, and the space shuttle engines aren't quite strong enough to push the combined weight of the shuttle and the big bloated external tank up off the ground.

That's what the two long white solid rocket boosters strapped onto the sides of the external tank are for. They lift the tank! Fortunately, it was not necessary to strap an infinite series of smaller and smaller rockets to the sides of the solid rocket boosters.

It is not widely known that just behind the main flight deck of the space shuttle is a small Starbucks adapted for use in zero gravity.

Source: internet

We have just as much hair all over our bodies as chimpanzees or monkeys or any other furry primate. Most of it is just very short and light. It's called "vellus hair" or "peach fuzz". I think it's bizarre that most of our thick hair is on the tops of our heads. Imagine if dogs looked like that! On second thought, maybe it's better if you don't imagine that.

Research shows that we humans lost all our body hair through evolution about a million years before somebody finally figured out how to purchase clothes at one of the first primitive Walmarts.

One theory says that we lost our all body hair in an attempt to avoid parasites like ticks, fleas, and lice, and that we've only kept the hair on our heads because other people think it's pretty. As proof, consider that you haven't seen many bald pregnant women.

There is a very special kind of louse that only lives in human clothing. DNA tests indicate that it evolved from a louse that only lives in human hair, and that this happened about 42,000 to 72,000 years ago. So, that's probably roughly when clothes first went on sale. There are no special lice that live in any form of footwear, so DNA testing cannot solve the troubling mystery of exactly at what point in the past Hello Kitty themed socks were invented.

Source:internet

If you were to live deep inside a cave, with no exposure to the outside world, eventually you would start sleeping roughly every 24 hours and 18 minutes, instead of exactly every 24 hours.

Under normal circumstances, our eyes sense light from the Sun, and our brains adjust to the standard 24 hour day, but we'd really always like to sleep that extra 18 minutes. Why is that? Scientists don't really know, but maybe it explains why everyone is so crabby all the time.

Some completely blind people, who sense no light at all, naturally live on a 24 hour, 18 minute day, and slowly march their schedule around the clock, out of phase with everybody else. I'm speaking from personal experience when I say that it's pretty annoying when you have a blind neighbor who mows his lawn in the middle of the night.

Our built-in tendency to live on a 24 hour, 18 minute day might seem to make sense if that was how long days were in the distant past, and the length of each day has been slowly speeding up. However, exactly the opposite is occurring. The length of each day has been gradually increasing, as the rotation of the Earth slows down because of the Moon's tidal forces. Half a billion years ago, days were 22 hours long. Four and a half billion years ago, they were six hours long. This didn't allow for a lot of variety in the television programming schedule.

A need for a longer day might also make sense if we were all from Mars. (We're not. Most of us are not. Let's just say that all the important people you know are not. If you don't already know that you are, you're not. It's best if you don't bring this up with your parents. Forget I mentioned any of this.) On Mars, each day is 24 hours and 39 minutes long. Scientists working on the Spirit and Opportunity Mars rover projects initially lived on a schedule based on Mars days, because the solar-powered rovers could only operate during daytime on Mars. The scientists wore special Mars watches so they'd know what time it was there. After a few months of this, and always sleeping weird hours, they were all pretty grumpy. Eventually they switched to a more practical, Earth-based schedule.

Sleeping in one continuous block during the night is an extremely recent development. Humans only started doing this when artificial lighting become readily available, and it was easier for everybody to stay up late. Before that, people tended to sleep in multiple chunks throughout the night, separated by periods of activity. Presumably, they would use this time to make trips to the ice box or watch crude infomercials performed by nocturnal travelling minstrels, which were quite popular during the Renaissance.

Source:internet

Trees

What are trees made out of? If you had asked me yesterday, I would have guessed that trees absorb raw materials from the ground through their roots, and use them to build new branches and roots as the tree grows. Or, perhaps trees are constructed by hardworking but underpaid gnomes and fairies during the night.

As it happens, that's not the case. Although roots take up a small amount of important nutrients, the majority of the mass of a tree is created from carbon dioxide absorbed from the air by the tree's leaves. That's right. It sounds crazy, but trees are mostly made out of air, and fairies aren't even involved.

When you burn wood, you're just dumping all that carbon dioxide back into the air where it originally came from. Don't do that. It annoys the fairies.

Source:internet

Hoba Meteorite

The Hoba meteorite is the largest to ever have been found on Earth.  The Hoba meteorite was found in Namibia, Africa in 1920.  This meteorite, which landed some 80,000 years ago, is composed of iron and weighs a hefty 60,000 kg.  It still lies in its original resting spot in Namibia, Africa.

The Williamette meteorite found in Oregon is the largest meteorite found in the United States.  It was found in 1902 in the Williamette Valley of Oregon.  It is now on display at the American Museum of Natural History.

Source:internet

 

A cockroach can survive for about a week or so without its head! If a cockroach becomes decapitated, the wound on their neck would clot and seal off. If this happens they will no longer be able to eat food, but insects can survive for weeks on only one meal. 

Most people usually think of the speed of light as being really fast. It's 671 million miles per hour. That seems tantalizingly zippy if you're caught in traffic.

However, once you think about the speed of light within the context of our solar system, it starts to seem unimpressive.

It takes about 1.3 seconds for light or radio waves to reach us from the Moon, which really isn't all that far away (it's only 20 times farther away than Australia is to the United States). This was an issue during the Apollo space program, because due to the round trip time of the radio signals, NASA had to wait about three seconds to hear the answer to every question they asked the astronauts.

When Mars is closest to the Earth, it takes light three minutes to travel between the two planets. If you asked a question to an astronaut on Mars, you'd have to wait at least six minutes for an answer, and Mars is usually a lot farther away than that. At its greatest distance, you'd have to wait 42 minutes, or even longer if the astronaut is watching Gilmore Girls. In the future, there will be no such thing as sending an "instant message" to your friends on the Mars base. There also won't be any day trading or free pizza delivery.