Why are scientists obsessed with the Black Sea? - Helen Farr and Jon Adams

460,768 views ใƒป 2021-10-21

TED-Ed


ืื ื ืœื—ืฅ ืคืขืžื™ื™ื ืขืœ ื”ื›ืชื•ื‘ื™ื•ืช ื‘ืื ื’ืœื™ืช ืœืžื˜ื” ื›ื“ื™ ืœื”ืคืขื™ืœ ืืช ื”ืกืจื˜ื•ืŸ.

ืชืจื’ื•ื: Ido Dekkers ืขืจื™ื›ื”: zeeva livshitz
00:07
It's midnight on September 16th, 2017,
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ื—ืฆื•ืช ื‘ 16 ื‘ืกืคื˜ืžื‘ืจ, 2017,
00:11
60 kilometers off the Bulgarian coast
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60 ืงื™ืœื•ืžื˜ืจ ืžื—ื•ืคื™ ื‘ื•ืœื’ืจื™ื”
00:14
and 2 kilometers beneath the Black Seaโ€™s surface.
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ื• 2 ืงื™ืœื•ืžื˜ืจ ืžืชื—ืช ืœืคื ื™ ื”ื™ื ื”ืฉื—ื•ืจ.
00:16
A remotely operated vehicle surveys the seabed,
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ืจื›ื‘ ืžื•ืคืขืœ ืžืจื—ื•ืง ืกื•ืงืจ ืืช ืงืจืงืขื™ืช ื”ื™ื,
00:19
transmitting video to researchers above as it goes.
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ืžืฉื’ืจ ื•ื™ื“ืื• ืœื—ื•ืงืจื™ื ืžืขืœ ื›ืฉื”ื•ื ืžืชืงื“ื.
00:23
Suddenly, it discerns another ghostly vessel in the gloom.
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ืคืชืื•ื, ื”ื•ื ืžื‘ื—ื™ืŸ ื‘ื›ืœื™ ืจืคืื™ื ื ื•ืกืฃ ื‘ืืคืœื”.
00:26
But this is a relic from another age.
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ืื‘ืœ ื–ื” ืฉืจื™ื“ ืžืขื™ื“ืŸ ืื—ืจ.
00:29
It's an undoubtedly ancient shipwreck,
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ื–ื• ืกืคื™ื ื” ื˜ืจื•ืคื” ืขืชื™ืงื”, ืื‘ืœ ื”ืชื•ืจืŸ ืกืคืกืœื™ ื”ื—ืชื™ืจื”,
00:31
but its mast, rowing benches, and some of its upper deck remain eerily intact.
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ื•ื—ืœืง ืžื”ืกื™ืคื•ืŸ ื”ืขืœื™ื•ืŸ ื ืฉืืจื• ืฉืœืžื™ื ื‘ืื•ืคืŸ ืžืคืชื™ืข.
00:37
It might be an ancient Roman ship, but its appearance doesnโ€™t quite match.
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ื–ื• ื™ื›ื•ืœื” ืœื”ื™ื•ืช ืื•ืœื™ ืกืคื™ื ื” ืจื•ืžืื™ืช ืขืชื™ืงื”, ืื‘ืœ ื”ืžืจืื” ืฉืœื” ืœื ืžืžืฉ ืžืชืื™ื.
00:41
Notably, its splayed rudder blade more closely resembles
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ื•ื ืจืื”, ืฉื”ื’ื” ื”ื›ื™ื•ื•ืŸ ืฉืœื” ื“ื•ืžื” ื™ื•ืชืจ
00:45
those depicted on an even older Greek vase.
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ืœืืœื” ืฉืžืชื•ืืจื™ื ืขืœ ืกืคื™ื ื•ืช ื™ื•ื•ื ื™ื•ืช ืขืชื™ืงื•ืช ืืคื™ืœื• ื™ื•ืชืจ.
00:49
To get a definitive answer, the research team takes three samples from the wreck
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ื›ื“ื™ ืœืงื‘ืœ ืชืฉื•ื‘ื” ื‘ืจื•ืจื”, ืฆื•ื•ืช ื”ื—ื•ืงืจื™ื ืœื•ืงื— ืฉืœื•ืฉ ื“ื•ื’ืžื™ื•ืช ืžื”ืกืคื™ื ื”
00:53
and radiocarbon dating confirms its ancient origins.
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ื•ืžืชืืจืš ืื•ืชืŸ ื›ื“ื™ ืœืืžืช ืืช ื”ืžืงื•ืจื•ืช ื”ืขืชื™ืงื™ื ืฉืœื”.
00:57
The ship is dated to between 350 and 410 BCE.
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ื”ืกืคื™ื ื” ืžืชื•ืืจื›ืช ื‘ื™ืŸ 350 ื• 410 ืœืคื ื™ ื”ืกืคื™ืจื”.
01:02
It is, in fact, the oldest intact shipwreck ever found.
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ื–ื•, ืœื›ืŸ, ื”ืกืคื™ื ื” ื”ื˜ืจื•ืคื” ื”ืฉืœืžื” ื”ื›ื™ ืขืชื™ืงื” ืฉืื™ ืคืขื ื ืžืฆืื”.
01:06
This ancient Greek vessel traversed the Black Seaโ€™s coasts
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ื”ืกืคื™ื ื” ื”ื™ื•ื•ื ื™ืช ื”ืขืชื™ืงื” ื”ื–ื• ืฉื˜ื” ื‘ื™ืŸ ื—ื•ืคื™ ื”ื™ื ื”ืฉื—ื•ืจ
01:09
during the time of Aristotle and has since rested in its depths,
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ื‘ืžื”ืœืš ืชืงื•ืคืช ืืจื™ืกื˜ื• ื•ืžืื– ื ื—ื” ื‘ืžืขืžืงื™ื•,
01:13
unseen and undisturbed, for almost 2,500 years.
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ื‘ืœืชื™ ื ืจืื™ืช ื•ืœื ืžื•ืคืจืขืช, ืœื‘ืขืจืš 2500 ืฉื ื”.
01:17
This was just one of 65 shipwrecks a research team discovered
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ื–ื• ื”ื™ืชื” ืจืง ืื—ืช ืž 65 ืกืคื™ื ื•ืช ื˜ืจื•ืคื•ืช ืฉืฆื•ื•ืชื™ ื—ื•ืงืจื™ื ื’ื™ืœื•
01:21
at the bottom of the Black Sea between 2015 and 2017.
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ื‘ืชื—ืชื™ืช ื”ื™ื ื”ืฉื—ื•ืจ ื‘ื™ืŸ 2015 ื• 2017.
01:25
Others date from the Roman, Byzantine, and Ottoman empires.
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ืื—ืจื•ืช ืžืชื•ืขื“ื•ืช ืžื”ืชืงื•ืคื” ื”ืจื•ืžืื™ืช, ื”ื‘ื™ื–ื ื˜ื™ืช, ื•ื”ืื™ืžืคืจื™ื” ื”ืขื•ืชืžืื ื™ืช.
01:28
And despite the centuries, theyโ€™ve all survived in remarkable condition.
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ื•ืœืžืจื•ืช ื”ืžืื•ืช, ื›ื•ืœืŸ ืฉืจื“ื• ื‘ืžืฆื‘ ืžื“ื”ื™ื.
01:32
So, why does the Black Sea contain so many well-preserved shipwrecks?
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ืื–, ืœืžื” ื”ื™ื ื”ืฉื—ื•ืจ ืžื›ื™ืœ ื›ืœ ื›ืš ื”ืจื‘ื” ืกืคื™ื ื•ืช ื˜ืจื•ืคื•ืช ืฉืžื•ืจื•ืช ื”ื™ื˜ื‘?
01:37
In prehistoric times,
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ื‘ื–ืžื ื™ื ื”ืคืจื”ื™ืกื˜ื•ืจื™ื,
01:38
the land surrounding the Black Sea hosted early human settlements.
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ื”ืื“ืžื” ืกื‘ื™ื‘ ื”ื™ื ื”ืฉื—ื•ืจ ืื™ืจื—ื” ื™ืฉื•ื‘ื™ื ืื ื•ืฉื™ื™ื ืžื•ืงื“ืžื™ื.
01:42
Eventually, it became a hub for trade, battle, and empire-building
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ืœื‘ืกื•ืฃ, ื”ื™ื ื”ืคื›ื” ืœืžืจื›ื– ืกื—ืจ, ืงืจื‘ื•ืช ื•ื‘ื ื™ื™ืช ืื™ืžืคืจื™ื•ืช
01:46
because of its strategic position
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ื‘ื’ืœืœ ื”ืžื™ืงื•ื ื”ืืกื˜ืจื˜ื’ื™ ืฉืœื”
01:48
between eastern and western Eurasian civilizations.
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ื‘ื™ืŸ ืฆื™ื•ื•ื™ืœื™ื–ืฆื™ื•ืช ื™ื•ืจื•ืืกื™ืืชื™ื•ืช ืžื–ืจื—ื™ื•ืช ื•ืžืขืจื‘ื™ื•ืช.
01:52
For thousands of years, it was traversed by merchants, pirates, and warriors.
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ื‘ืžืฉืš ืืœืคื™ ืฉื ื™ื, ืขื‘ืจื• ื‘ื” ืกื•ื—ืจื™ื, ืคื™ืจืื˜ื™ื ื•ืœื•ื—ืžื™ื.
01:56
And with sustained seafaring activity came inevitable losses.
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ื•ืขื ืคืขื™ืœื•ืช ื™ืžื™ืช ืžืชืžืฉื›ืช ื”ื’ื™ืขื• ืื‘ื“ื ื™ื ื‘ืœืชื™ ื ืžื ืขื™ื.
02:01
But unlike other bodies of water in the region,
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ืื‘ืœ ื‘ื ื™ื’ื•ื“ ืœื’ื•ืคื™ ืžื™ื ืื—ืจื™ื ื‘ืื™ื–ื•ืจ,
02:03
the Black Sea is a particularly deep, semi-enclosed basin.
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ื”ื™ื ื”ืฉื—ื•ืจ ืขืžื•ืง ื‘ืžื™ื•ื—ื“, ื‘ืื’ืŸ ืกื’ื•ืจ ืœืžื—ืฆื”.
02:08
Seasonal changes usually cause the layers within a contained body of water
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ืฉื™ื ื•ื™ื™ื ืขื•ื ืชื™ื™ื ื‘ื“ืจืš ื›ืœืœ ื’ื•ืจืžื™ื ืœืฉื›ื‘ื•ืช ื‘ืชื•ืš ื’ื•ืฃ ืžื™ื ืžื•ื›ืœ
02:12
to mix together, oxygenating the water.
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ืœื”ืชืขืจื‘ื‘ ื™ื—ื“, ื•ืœื—ืžืฆืŸ ืืช ื”ืžื™ื.
02:15
But because the Black Sea is fed with fresh water from European rivers,
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ืื‘ืœ ื‘ื’ืœืœ ืฉื”ื™ื ื”ืฉื—ื•ืจ ืžื•ื–ืŸ ื‘ืžื™ื ืžืชื•ืงื™ื ืžื ื”ืจื•ืช ืืจื•ืคืื™ื,
02:19
and saltwater from the Mediterranean Sea, it contains two distinct layers.
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ื•ืžื™ ืžืœื— ืžื”ื™ื ื”ืชื™ื›ื•ืŸ, ื”ื•ื ืžื›ื™ืœ ืฉืชื™ ืฉื›ื‘ื•ืช ืžื•ื‘ื—ื ื•ืช.
02:24
The denser saltwater flows beneath the freshwater,
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ืžื™ ื”ืžืœื— ื”ื“ื—ื•ืกื™ื ื™ื•ืชืจ ืžืชื—ืช ืœืžื™ื ื”ืžืชื•ืงื™ื,
02:27
where it remains permanently,
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ืฉื ื”ื ื ืฉืืจื™ื ื‘ืื•ืคืŸ ืงื‘ื•ืข,
02:29
making the Black Sea the worldโ€™s largest meromicticโ€” or un-mixingโ€” basin.
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ื•ื”ื•ืคื›ื™ื ืืช ื”ื™ื ื”ืฉื—ื•ืจ ืœืื’ืŸ ื”ืžืจื•ืžื™ืงื˜ื™ - ืื• ื”ืœื ืžืชืขืจื‘ื‘ -- ื”ื’ื“ื•ืœ ื‘ืขื•ืœื.
02:34
Oxygen doesnโ€™t reach its lower, saltier zone,
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ื—ืžืฆืŸ ืœื ืžื’ื™ืข ืœืื–ื•ืจื™ื ื”ื ืžื•ื›ื™ื ื•ื”ืžืœื•ื—ื™ื ื™ื•ืชืจ.
02:37
which creates the ideal environment for preservation,
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ืžื” ืฉื™ื•ืฆืจ ืชื ืื™ื ืื™ื“ื™ืืœื™ื ืœืฉื™ืžื•ืจ,
02:41
and is why the Black Sea has been called โ€œthe worldโ€™s biggest pickle jar.โ€
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ื•ืœื›ืŸ ื”ื™ื ื”ืฉื—ื•ืจ ื ืงืจื โ€œืฆื ืฆื ืช ื”ืฉื™ืžื•ืจื™ื ื”ื’ื“ื•ืœื” ื‘ืขื•ืœื.โ€
02:45
In other bodies of water, marine organisms decompose materials over time.
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ื‘ื’ื•ืคื™ ืžื™ื ืื—ืจื™ื, ืื•ืจื’ื ื™ื–ืžื™ื ื™ืžื™ื™ื ืžืคืจืงื™ื ื—ื•ืžืจื™ื ื‘ืžืฉืš ื”ื–ืžืŸ.
02:50
Had the ancient Greek ship sunk in the Mediterranean, for example,
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ืื ื”ืกืคื™ื ื” ื”ื™ื•ื•ื ื™ืช ื”ืขืชื™ืงื” ื”ื™ืชื” ื˜ื•ื‘ืขืช ื‘ื™ื ื”ืชื™ื›ื•ืŸ, ืœื“ื•ื’ืžื”,
02:54
there would likely be no organic material left today.
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ื›ื ืจืื” ืœื ื”ื™ื” ื ืฉืืจ ื—ื•ืžืจ ื‘ื™ื•ืœื•ื’ื™ ื”ื™ื•ื.
02:57
But in the depths of the Black Sea,
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ืื‘ืœ ื‘ืžืขืžืงื™ ื”ื™ื ื”ืฉื—ื•ืจ,
02:59
only anaerobic bacteriaโ€” those that donโ€™t require oxygenโ€” can survive.
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ืจืง ื‘ืงื˜ืจื™ื•ืช ืื ืืจื•ื‘ื™ื•ืช -- ืืœื• ืฉืœื ื“ื•ืจืฉื•ืช ื—ืžืฆืŸ -- ื™ื›ื•ืœื•ืช ืœืฉืจื•ื“.
03:04
This is why ancient ships can still be found carrying their original cargo,
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ืœื›ืŸ ืกืคื™ื ื•ืช ืขืชื™ืงื•ืช ืขื“ื™ื™ืŸ ื™ื›ื•ืœื•ืช ืœื”ื™ืžืฆื ื›ืฉื”ืŸ ื ื•ืฉืื•ืช ืืช ื”ืžื˜ืขืŸ ื”ืžืงื•ืจื™,
03:08
with carvings in their wood, and their rigging still assembled.
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ืขื ื—ืจื™ื˜ื•ืช ื‘ืขืฅ ืฉืœื”ืŸ, ื•ื”ื—ื™ื‘ื•ืจื™ื ืฉืœื”ืŸ ืขื“ื™ื™ืŸ ืžื•ืจื›ื‘ื™ื.
03:12
Among the recent findings was a medieval Italian merchant ship,
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ื‘ื™ืŸ ื”ืžืžืฆืื™ื ื”ืื—ืจื•ื ื™ื ื”ื™ืชื” ืกืคื™ื ืช ืกื•ื—ืจ ืื™ื˜ืœืงื™ืช ืžื™ืžื™ ื”ื‘ื™ื ื™ื™ื,
03:16
likely from around the time Italy had a virtual monopoly over Black Sea trade.
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ื›ื ืจืื” ืžืกื‘ื™ื‘ื•ืช ื”ื–ืžืŸ ืฉืื™ื˜ืœื™ื” ื”ื™ืชื” ืžื•ื ื•ืคื•ืœ ืžื•ื—ืœื˜ ื‘ื™ื ื”ืฉื—ื•ืจ.
03:21
Venetian traveler Marco Polo wouldโ€™ve probably been familiar
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ื”ื—ื•ืงืจ ื”ื•ื•ื ืฆื™ืื ื™ ืžืจืงื• ืคื•ืœื• ื›ื ืจืื” ื”ื›ื™ืจ
03:25
with this kind of ship.
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ืกื•ื’ ื–ื” ืฉืœ ืกืคื™ื ื”.
03:27
Although vessels like this one helped to modernize Europe,
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ืœืžืจื•ืช ืฉืกืคื™ื ื•ืช ื›ืžื• ื–ื• ืขื–ืจื• ืœืžื•ื“ืจื ื™ื–ืฆื™ื” ืฉืœ ืื™ืจื•ืคื”,
03:30
contemporary scholars had never before seen such a complete example.
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ืžืœื•ืžื“ื™ื ืขื›ืฉื™ื•ื•ื™ื™ื ืžืขื•ืœื ืœืคื ื™ ื›ืŸ ืœื ืจืื• ื›ื–ื• ื“ื•ื’ืžื” ืžื•ืฉืœืžืช.
03:34
And it was largely intactโ€”
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ื•ื”ื™ื ื”ื™ืชื” ื›ืžืขื˜ ืœื’ืžืจื™ ืฉืœืžื” --
03:36
a shipโ€™s boat still lying on its deck,
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ืกื™ืจื” ืฉืœ ื”ืกืคื™ื ื” ืขื“ื™ื™ืŸ ื ื—ื” ืขืœ ื”ืกื™ืคื•ืŸ,
03:38
even though some seven centuries had passed.
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ืืคื™ืœื• ืฉืฉื‘ืข ืžืื•ืช ืขื‘ืจื•.
03:41
Many of the 65 ships that were recently uncovered
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ื”ืจื‘ื” ืž 65 ื”ืกืคื™ื ื•ืช ืฉื”ืชื’ืœื• ืœืื—ืจื•ื ื”
03:44
have retained their original forms.
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ืฉืžืจื• ืขืœ ื”ืฆื•ืจื” ื”ืžืงื•ืจื™ืช ืฉืœื”ืŸ.
03:47
But while there are far fewer degradative forces at play in the Black Seaโ€™s depths,
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ืื‘ืœ ื‘ื–ืžืŸ ืฉื™ืฉ ื”ืจื‘ื” ืคื—ื•ืช ื›ื•ื—ื•ืช ืžืคืจืงื™ื ืžืฉื—ืงื™ื ื‘ืžืขืžืงื™ ื”ื™ื ื”ืฉื—ื•ืจ,
03:51
anaerobic bacteria do gradually weaken organic materials.
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ื‘ืงื˜ืจื™ื•ืช ืื ืืจื•ื‘ื™ื•ืช ืžื—ืœื™ืฉื•ืช ื‘ืื™ื˜ื™ื•ืช ื—ื•ืžืจื™ื ืื•ืจื’ื ื™ื.
03:55
When researchers lifted a plank from the ancient Greek wreck for dating,
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ื›ืฉื—ื•ืงืจื™ื ื”ืจื™ืžื• ืœื•ื— ืžื”ืกืคื™ื ื” ื”ื™ื•ื•ื ื™ืช ื”ืขืชื™ืงื” ืœืชื™ืืจื•ืš,
03:59
it broke under its own weight.
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ื”ื•ื ื ืฉื‘ืจ ืชื—ืช ืžืฉืงืœื•.
04:01
While the ships are exceptionally well-preserved, they're also fragile.
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ื‘ื–ืžืŸ ืฉื”ืกืคื™ื ื•ืช ื ืฉืžืจื• ื‘ืื•ืคืŸ ืžืขื•ืœื”, ื”ืŸ ื’ื ืฉื‘ื™ืจื•ืช.
04:05
This makes it impossible to bring them to the surface intact.
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ื–ื” ื”ื•ืคืš ืืช ื–ื” ืœื‘ืœืชื™ ืืคืฉืจื™ ืœื”ืจื™ื ืื•ืชืŸ ืœืคื ื™ ื”ืฉื˜ื— ืฉืœืžื•ืช.
04:09
Scientists may carefully remove and study select objects from the wreckages.
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ืžื“ืขื ื™ื ืื•ืœื™ ื™ื•ื›ืœื• ืœื”ืกื™ืจ ื‘ื–ื”ื™ืจื•ืช ื•ืœื—ืงื•ืจ ืขืฆืžื™ื ื ื‘ื—ืจื™ื ืžื”ืฉื‘ืจื™ื.
04:13
But the sunken ships will remain protected where they are,
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ืื‘ืœ ื”ืกืคื™ื ื•ืช ื”ื˜ื‘ื•ืขื•ืช ื™ืฉืืจื• ืžื•ื’ื ื•ืช ื‘ืžืงื•ื ื‘ื• ื”ืŸ ื ืžืฆืื•ืช,
04:17
perhaps among thousands of othersโ€”
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ืื•ืœื™ ื‘ื™ืŸ ืืœืคื™ ืื—ืจื•ืช --
04:19
deep beneath us, suspended in time, at the bottom of the Black Sea.
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ืขืžื•ืง ืžืชื—ืชื™ื ื•, ืชืœื•ื™ื•ืช ื‘ื–ืžืŸ, ื‘ืชื—ืชื™ืช ื”ื™ื ื”ืฉื—ื•ืจ.
ืขืœ ืืชืจ ื–ื”

ืืชืจ ื–ื” ื™ืฆื™ื’ ื‘ืคื ื™ื›ื ืกืจื˜ื•ื ื™ YouTube ื”ืžื•ืขื™ืœื™ื ืœืœื™ืžื•ื“ ืื ื’ืœื™ืช. ืชื•ื›ืœื• ืœืจืื•ืช ืฉื™ืขื•ืจื™ ืื ื’ืœื™ืช ื”ืžื•ืขื‘ืจื™ื ืขืœ ื™ื“ื™ ืžื•ืจื™ื ืžื”ืฉื•ืจื” ื”ืจืืฉื•ื ื” ืžืจื—ื‘ื™ ื”ืขื•ืœื. ืœื—ืฅ ืคืขืžื™ื™ื ืขืœ ื”ื›ืชื•ื‘ื™ื•ืช ื‘ืื ื’ืœื™ืช ื”ืžื•ืฆื’ื•ืช ื‘ื›ืœ ื“ืฃ ื•ื™ื“ืื• ื›ื“ื™ ืœื”ืคืขื™ืœ ืืช ื”ืกืจื˜ื•ืŸ ืžืฉื. ื”ื›ืชื•ื‘ื™ื•ืช ื’ื•ืœืœื•ืช ื‘ืกื ื›ืจื•ืŸ ืขื ื”ืคืขืœืช ื”ื•ื•ื™ื“ืื•. ืื ื™ืฉ ืœืš ื”ืขืจื•ืช ืื• ื‘ืงืฉื•ืช, ืื ื ืฆื•ืจ ืื™ืชื ื• ืงืฉืจ ื‘ืืžืฆืขื•ืช ื˜ื•ืคืก ื™ืฆื™ืจืช ืงืฉืจ ื–ื”.

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