As far as we know, around 4,500 million years ago this rock that we live on coalesced from
the dust and debris left over from the formation of our sun. Without airplanes, pizza delivery,
or the Internet, things moved more slowly across the early earth than they do today.
For example, from isolated puddles of water, the oceans formed over the course of 400 to
800 million years. That’s how long it would take for your hair to grow around the earth
– twice. In that same time, bacterial life did spread across the watery globe. Higher
plants and animals, on the other hand, took much longer to develop and disperse. But we’re
going to skip those 3 billion years (during which your hair would have grown to the moon)
来讨论我们自己 现代人 我们比我们自己的头发更快
and talk about us, Homo sapiens. We were much faster than our own hair, which would have
grown a meager 27km in the 180,000 years we took to cross Africa and reach all the unfrozen
In many of these places we were able to develop useful practices like agriculture, but because
we were scattered across the globe, the best ideas and tastiest regional foods could only
gain ground through trade or human migration. Wheat, for example, was domesticated around
8500BC to make porridge. Actually, some speculate it might have been for beer, but either way
wheat made it from the Fertile Crescent to both the Atlantic and the Pacific by roughly
6000km in 6000 years might seem like a blistering pace, but just wait for the Middle Ages! The
黑死病和印刷机 每一个都在小于100年内 传遍整个欧洲
bubonic plague and the printing press each spread across Europe in less than a hundred
years, bringing death and literacy to the populace before their hair could have even
grown 15 meters. In the 20th century, mania for both the Beatles and the Hula hoop raced
around the world in a year or two. Now even a year is a long time. With millions of people
jetsetting across the globe every day, diseases such as SARS can vacation almost anywhere
在短短数周内 而0和1组成了这个视频 平均下来
within a few short weeks. And the 0s and 1s that make up this video take, on average,
传播到你那里只需要少于1/10秒 那是一纳米的一半 或两个原子
less than a tenth of a second to get to you – that’s about half a nanometer, or two atoms,
of hair growth.
In short – the pace of travel on earth has really sped up!
But how do we know this stuff? How do we know what happened on earth before the records
of written history? Why do we think the earth is 4,500,000,000 years old? And what on earth
is going to happen in the next 45 years?
Welcome to the story of what we know about the earth and how we know that we know it.
This is MinuteEarth.