What happens to our bodies after we die? - Farnaz Khatibi Jafari

8,437,619 views ・ 2016-10-13

TED-Ed


Please double-click on the English subtitles below to play the video.

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Since the dawn of humanity,
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an estimated 100.8 billion people have lived and died,
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a number that increases by about .8% of the world's population each year.
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What happens to all of those people's bodies after they die
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and will the planet eventually run out of burial space?
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When a person's heart stops beating,
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the body passes through several stages before it begins decomposing.
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Within minutes after death,
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the blood begins settling in the lower-most parts of the body.
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Usually eight to twelve hours later,
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the skin in those areas is discolored by livor mortis, or post-mortem stain.
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And while at the moment of death the body's muscles relax completely
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in a condition called primary flaccidity,
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they stiffen about two to six hours later in what's known as rigor mortis.
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This stiffening spreads through the muscles,
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and its speed can be affected by age, gender, and the surrounding environment.
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The body also changes temperature,
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usually cooling off to match its environment.
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Next comes decomposition,
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the process by which bacteria and insects break apart the body.
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Many factors affect the rate of decomposition.
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There is, however, a basic guide of the effect of the environment on decompositon
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called Casper's Law.
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It says that if all other factors are equal,
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a body exposed to air decomposes twice as fast as one immersed in water
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and eight times as fast as one buried in earth.
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Soil acidity also greatly affects bone preservation.
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High-acidity soils with a pH of less than 5.3
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will rapidly decompose bone,
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whereas in a neutral or basic soil with a pH of 7 or more,
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a skeleton can remain in relatively good condition for centuries.
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Different cultures throughout history have developed unique approaches to burials.
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As far back as the first Neanderthal burials,
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death was accompanied by rituals,
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like the positioning, coloring, or decorating of corpses.
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Traditional Christian burials decorate the body in dress,
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while in traditional Islam,
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a body is wrapped in a piece of ritual fabric
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with the face oriented toward Mecca.
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Traditional Hindus ceremonially burn the body,
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and Zoroastrians, followers of one of the oldest monotheistic religions,
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traditionally place bodies atop a tower to expose them to the Sun
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and scavenging birds.`
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Before the Industrial Revolution, burials were simple and accessible.
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These days, with suitable burial land running out in high-population areas,
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purchasing private gravesites can be costly,
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and many people can't afford simple burials.
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Even cremation, the second most common burial practice in the world,
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comes with a high cost.
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As for the question of running out of space,
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the issue isn't so much about total land in the world
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as it is that large populations cluster together within cities.
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Most of the big cities in the world
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may run out of suitable burial grounds within a century.
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For London, it's even sooner.
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That may happen by 2035.
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So are there alternatives to traditional burials
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that might help with the space issue?
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In some countries, skyscraper cemeteries enable vertical burials.
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Some options focus on the body's relationship with the environment.
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Promession, for example, freeze-dries and pulverizes the body,
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creating a powder that can turn into compost
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when mixed with oxygen and water.
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There are also green burials that use special materials,
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such as biodegradable caskets,
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urns that sprout trees,
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and burial suits that grow mushrooms.
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Eternal reefs take that concept to the depths of the ocean
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using a mixture of ashes and cement to create marine habitats for sea life.
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Death is an inevitable part of the human condition,
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but how we treat bodies and burials continues to evolve.
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We may each have different spiritual,
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religious,
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or practical approaches to dying,
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but the ever-increasing demand for burial space
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might give us a push to be creative
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about where our bodies go after the final stages of life.
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