If this were not the case, water would freeze from the bottom up at 0˚C, and all creatures living under water would die.
만약이렇지않다면, 물은섭씨0도에서바닥부터얼게될것이고, 물속에사는생명체들은죽게될것이다.
Therefore, underwater creatures can survive the freezing winter while living under water that is between 0˚C and 4˚C.
그러므로물밑에사는모든생명체는섭씨0도와4도사이의물속에살면서몹시추운겨울을견딜수있다.
Water is surely nature's greatest gift to us!
물은확실히우리에게주는자연의거대한선물인것이다!
The Earth Travels Really Fast
지구는정말빨리움직인다.
Which do you think travels faster, an airplane or the earth?
당신은비행기와지구중어느게더빨리움직인다고생각하는가?
An ordinary passenger airplane can travel at the speed of about 800 kilometers per hour.
일반적인여객기는시속800km의속도로이동한다.
Although the earth seems motionless, it spins much faster than you might think.
지구는움직임이없는것처럼보이지만, 지구는여러분이생각하는것보다훨씬빨리돈다.
Let's do some simple math here to figure out how fast our planet is spinning.
우리의행성이얼마나빨리도는지를계산해보기위해간단한수학을해보자.
The earth is 40,044 kilometers round at the equator.
지구는적도둘레가40,044km이다.
40,044 kilometers divided by 24 hours is 1,668.5
kilometers per hour, or about 463 meters per second.40,044km를24시간으로나누면시간당1,668.5km, 혹은초당약463m가된다.
This rotation speed is even greater than 340 meters per second, which is the speed of sound.
이회전속도는초속340m보다훨씬높은것인데, 초속340m는소리의속도이다.
So the earth is spinning faster than the speed of a passenger airplane or the speed of sound.
따라서지구는여객기의속도나소리의속도(음속)보다빠르게회전하고있다.
The earth also revolves around the sun.
지구는또한태양주위를돈다.
How fast is this rotation?
이회전은얼마나빠를까?
The speed of the earth moving around the sun is 29 kilometers per second.
태양주위에서움직이는지구의속도는초속29km이다.
Can you imagine how fast this speed is?
이속도가얼마나빠른지상상할수있는가?
Believe it or not, it's almost 90 times greater than the speed of sound!
믿기어렵겠지만, 이것은소리의속도(음속)보다거의90배정도빠르다!
But we don't have to worry about feeling dizzy while living on this fast-moving planet.
하지만우리는이렇게빨리움직이는행성에살면서어지러움을느끼는것에대해걱정하지않아도된다.
Thanks to gravity, we're all alive.
중력덕분에, 우리는모두살아있으니까.
A Heavenly Show
천상의쇼
Looking up at the night sky, you will probably notice that it is all one color: a black blanket studded with stars and the occasional appearance of the moon.
밤하늘을올려다보면, 당신은아마도그것이전부한가지색이라는걸알게될것이다. 즉, 별과가끔씩나타나는달이수놓인까만담요같아보일것이다.
However, you might be surprised to learn that if you took a trip to the Arctic or Antarctic, then you would see a colorful display.
하지만, 당신은북극이나남극으로여행을가게되면, 화려한장광을보게될것이라는걸알게되면놀랄것이다.
Astronomers call these light displays, auroras, and they appear most commonly at the northern or southern poles of our planet.
When wiggling through to the earth's atmosphere and crashing into the shield, the particles start to act like bumper cars and colorful lights bounce off.
Dust consists of particles in the atmosphere that come from various sources such as soil dust lifted by wind, volcanic eruptions, and pollution produced by automobiles and plants.
For example, pollution in the air contributes to minor problems such as itchy eyes, coughing, sneezing, and headaches.
예를들면, 공기중의오염물질은눈의가려움, 기침, 재채기, 두통과같은소소한문제들의원인이된다.
Dust can also be a major contributing factor to severe diseases and allergies.
또한먼지는심각한질병이나알레르기의주요원인이될수도있다.
In addition, coal dust is responsible for black lung disease that occurs among coal miners.
게다가, 석탄먼지(분탄)는광부들에게발생하는탄폐증의원인이된다.
On the other hand, dust has its advantages, too.
반면에먼지는이로운점도갖고있다.
First, the water vapor in the clouds condenses on dust particles in the form of water drops.
첫째, 구름속수증기는먼지입자와응축하여물방울의형태가된다.
While traveling in the clouds, these water drops get big enough to fall onto the earth as rain.
구름안을돌아다니다가, 이러한물방울들은비의형태로지표면에떨어질만큼커진다.
Second, the dust particles present in the atmosphere spread the sun's rays in all directions.
둘째, 대기중에존재하는먼지입자는모든방향으로태양광선을분산시킨다.
This effect explains why it doesn't get completely dark outside, even one or two hours after sunset.
이러한현상(효과)은일몰후한시간이나두시간후에도바깥이완전히어두워지지않는이유를설명해준다.
Third, dust particles make the sun's rays look great at sunrise and sunset.
셋째, 먼지입자는일출이나일몰때태양광선을멋지게보이도록만든다.
Clouds in the sky make the rays at these times of day particularly beautiful.
하늘의구름은하루이맘때쯤의태양광선을특별히아름답게만들어준다.
Finally, some dust particles in the atmosphere gather pollutants, which can help to trap heat within the air and cool the atmosphere closer to the earth's surface.