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  • At one point or another you might have heard that only a few centuries ago, people thought

  • the Earth was flat. People believed that if you sailed too far out, you would reach the

  • literal edge of the world and fall off. Well this is quite misleading as people have known

  • the Earth to be spherical since the time of ancient Greece. The earliest known evidence

  • for the concept of a spherical Earth can be traced back to Greek philosophers during the

  • 6th century BC. A few centuries later, no educated person thought the world was anything

  • but round. This idea slowly spread and gradually became accepted as fact all across the globe.

  • And while some cultures held on to the flat-earth-idea for quite a while, by the time of the Middle Ages,

  • the Earth was most definitely a globe. Medieval books and illustrations repeatedly

  • make the point that the earth is round and not flat. The confusion actually comes from

  • historians looking back and misinterpreting certain events and literature.

  • While people may not have believed the Earth to be flat as much as we thought. For the

  • longest time, we definitely believed ourselves to be the center of the universe. It's called

  • the geocentric model and it actually makes a lot of sense. From our point of view down

  • here on the surface, it actually looks like the Sun, Moon, visible planets, and distant

  • stars orbit around a stationary Earth. It wasn't until the late 16th century that the

  • geocentric model was gradually superseded by the heliocentric model where the Sun is

  • the center and the Earth is simply one planet among many orbiting around it.

  • Earth is the only planet not named after a Greek or Roman god or goddess. The name comes

  • from old Germanic words such as ertha and ert. And while its name is of course different

  • in every language, what they all have in common is that almost every name derived from a word

  • that means "soil" or "ground". For example here in Sweden, the planets name is Jorden

  • and the word for soil is jord. The Latin names Terra and Tellus can also be used as synonyms.

  • We all know that one day here on Earth is 24 hours long and the reason we have days

  • in the first place is because the earth is rotating on it's own axis while orbiting the

  • sun. But if we do the calculations, we find that for the Earth to make one full revolution

  • it only takes 23:56:04. This is called a sidereal day and is actually not the way we calculate

  • one full day here on Earth. This is because, the unit of time known as day also has to

  • account for the orbit around our sun. Let's take this specific point on Earth. Now, let's

  • simulate a day passing by rotating the planet. Once the point reaches the same position,

  • one sidereal day has passed or 23:56:04. What makes a solar day 24 hours long is the location

  • of this spot relative to the sun. While the Earth has definitely made a full rotation,

  • it also moved a bit in it's year long orbit around the sun. Therefor it actually needs

  • to rotate a bit more so that this point is now facing the sun like it did when it started.

  • And just like a day isn't really 24 hours long, a year isn't really 365 days long. The

  • reason for this is not the same however. We count days based on the rotation of the Earth,

  • while the year is based on the orbital period around the sun. And this is the problem. The

  • day/night cycle has nothing to do with the yearly cycle. Yet a year is determined by

  • the day/night cycle. This result in one year being 365.2425 days long. This is where leap

  • years come into play. Every forth year we squeeze in an extra day at the end of February

  • because the Earth's spin and the Earth's orbit around the sun every so slightly overlap.

  • Without leap years, our calenders would get confused and summer would eventually be winter

  • and vice versa.

  • Liquid water is a crucial part for all life here on Earth. Yet the origin of our planet's

  • water remains unclear. More specifically, why do Earth have so much more liquid water

  • compared to almost every other body in the solar system. I say almost every other body,

  • because one of Jupiter's moons called Europa, may contain more than twice as much liquid

  • water found here on Earth. Even though it's smaller then our Moon. This subsurface ocean

  • is trapped under a vast sheet of ice and could potentially contain life.

  • While life may or may not be so abundant in the universe, the Earth is truly teaming with

  • it. It is everywhere and seems to somehow survive everything. Top of mount everest?

  • No problem. Bottom of the ocean? Of course. At the edge of the atmosphere? Sure. Inside

  • NASA and ESA clean rooms which are meant to be sterilized inhospitable environments?

  • Are you even fucking trying m8. What I'm saying is that life.. uh... finds a way. It truly

  • does. Let's take a walk outside and bring a spoon with you. Good. Now dig up some soil

  • and take a good look at it. This spoonful of soil contains more living organism than

  • there are humans on this planet. Soil is a paradise for tiny creatures eating and pooping

  • and reproducing their way toward glorious soil fertility. Luckily we can't see any of

  • that, otherwise I would've flipped my shit by now. In an equally mind-fuck fashion, for

  • every grain of sand on Earth, there are roughly 10,000 stars in the universe.

  • Welcome to Earth...

  • Texas. The only city on Earth named Earth. Well at least in English.

  • It has a population of around 1000 and was originally called Fairlawn. However they soon

  • learned of another city by that name so the townspeople sent in suggestions for a new

  • one, and thus Earth became the first Earth on Earth.

  • Most of us know that Mt. Everest is the tallest point on the planet. Well, no it isn't actually.

  • It's only the highest mountain by elevation above sea level. The tallest point on Earth,

  • as in either the greatest distance from the center or the least distance to space is

  • Mt. Chimborazo. This is because the Earth is not really a perfect sphere but something called

  • a spheroid. This basically means that the Earth is a bit thicker along the equator compared

  • to the poles. And as Mt. Chimborazo is very close to the equator it just barely beats Mt. Everest.

  • The Earth has been the home to every living thing in the universe that we know of. But

  • why is that? If the universe has existed for so many billions of years, why is space so

  • seemingly empty? Well, that's not exactly what this video about, and I have in fact

  • talked about this in numerous videos before, but a possible answer or perhaps clue to that

  • question is the Earth itself. Because Earth is extremely complicated. Its creation and

  • what lead to our existence is nothing short of an accident. Or rather a very long list

  • of accidents. It all started roughly 4.54 billion years ago when our solar system was

  • nothing but a gigantic cloud of dust and particles known as a solar nebula. Due to gravity, things

  • eventually started spinning and the sun began to take form in the center while planets and

  • smaller bodies formed around it. Out of shear luck, the Earth formed at just the right distance

  • so it would not be too hot or too cold for us humans to exist many eons later. The so

  • called habitable or Goldilocks zone. We where also fortunate enough to have a bro like Jupiter

  • to catch many nasty comets that could potentially hit the Earth and annihilate us. Much like

  • what happened to the dinosaurs. Early in its evolution the Earth was a hellish planet with

  • intense volcanism and frequent collisions with meteorites and other bodies. One of these

  • collisions is believed to have created the moon. The Earth collided with a body the size

  • of mars which ejected enormous amounts of debris into orbit. This debris eventually

  • clumped together to form the Moon. Not only that, but the collision itself is thought

  • to be responsible for tilting the Earth at an angle, giving us seasons. All the volcanic

  • activity during this period began the creation of Earth's atmosphere. In turn, the comets

  • brought with them ice that melted and helped to cool this hellish landscape to create the

  • Earth's crust and possibly the oceans. Roughly 3.8 billion years ago, the Earth had cooled

  • enough for life to take form. However, it wasn't until 2 billion years ago when photosynthetic

  • life began to appear, enriching the atmosphere with life essential oxygen.

  • We still don't know how life began on this planet,

  • but it's quite evident that a lot is required for it to begin. You can't just have an Earth

  • like planet and expect that to be enough. Of course, this is all assuming that an Earth

  • like planet is required for life to exist.

  • Oh and 63 Earths can fit inside Uranus.

  • Hello people, this video was part of a collaboration with List25. So if you want to, you can click this

  • little thumbnail thingy (annotation) to check out a video on their channel.

At one point or another you might have heard that only a few centuries ago, people thought

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トップ10の事実 - 地球 (Top 10 Facts - Earth)

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    吳承宇 に公開 2021 年 01 月 14 日
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