استماع TOEFL C1: Antikythera Mechanism

Now we've got a few minutes before we leave for today. So I'll touch on an interesting subject.

More than a hundred years ago

an extraordinary mechanism was found by sponge divers at the bottom of the sea near the island of Antikythera.

It astonished the whole international community of experts on the ancient world.

Was it an astrolabe? Or Was it an an astronomical clock?

For decades, scientific investigation failed to yield much light and relied more on imagination than the facts.

However research over the last half century has begun to reveal its secrets.

The machine dates from around the end of the 2nd century B.C.

and is the most sophisticated mechanism known from the ancient world.

It is now known as the Antikythera mechanism.

Now, when the Antikythera Mechanism was found, it was submerged in a shipwreck.

Of course, it was in terrible condition, some parts entirely corroded away.

It was a fairly small device, about the size of a shoebox,

a meticulous mesh of gears within a wooden shell.

There were rotating dials and other markings on the top,

with words and icons showing the Sun and moon,

and different points of reference in the stars.

In other words, this was a device that could track the phases of the moon.

This kind of thing would be invaluable during a ship's journey at sea.

Since then, scientists have been carefully looking at the device for clues on where and when it was made,

and they concluded that it dated back to somewhere between 150 and 100 BCE.

In other words, it was about a 50 year time span it could have been invented and used within.

So! this was an important breakthrough in the field of archaeology...

because before we found the Antikythera Mechanism,

the only evidence we could find of a similar star-tracking devices was a thousand years earlier.

Now, as I just said earlier,

when the Antikythera Mechanism was found, it was entirely corroded away.

This is because the Antikythera Mechanism is made entirely of bronze.

Well... this would make sense as bronze was widely used in Greece back then.

In fact, because bronze was malleable,

it was easy to melt the the metal down into bronze coins,

which was used as money in Greece.

Okay! Back to where I said about the Antikythera Mechanism being made of bronze.

You see.. Bronze easily corrodes underwater,

so after spending nearly 2,000 years at the bottom of the sea,

symbols, of course, were rubbed down to almost nothing by water and silt,

and the gears, as you can imagine...

had been crusted together into one mass with rust and other deposits.

So, cleaning it was an uphill battle, and never completely successful.

We could really only get a solid idea of how many gears were laid out

after using gamma-rays to see inside,

kind of similar to the way X-rays are used to see your bones.

So! After scanning the insides,

we found an incredibly complex creation.

The plethora of gears didn't only track the phases of the moon,

The Antikythera Mechanism also kept track of the lunar year and the solar year.

In addition, they ticked to align with the earth's own rotation,

and could accurately predict when an eclipse would happen.

This is all amazing,

but the one particularly mind-blowing trait of this device was that it was so incredibly precise

that it actually accounted for an irregularity in our moon's orbit

that would require some extremely complex math to replicate in a mechanical device.

I suppose I could say the Antikythera Mechanism is an amazing piece of engineering

that revolutionized the archaeological community.