The Threat to Earth

Extras

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  Critical Condition: Health in Black America Preview

  After centuries of pseudoscience, researchers examine the causes of racial health disparities.

  0:30
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  How Deadly Was the Musket?

  A team of experts put an 18th-century musket to the test — revealing how deadly it really was.

  4:57
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  The World’s First Combat Submarine

  Its nickname was the “Turtle”.

  10:49
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  These Smart Glasses Know Who You Are, and Much More

  Two students created glasses that can identify people on the street, without them knowing.

  4:18
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  Why Just Planting Trees Won’t Save the Planet

  Could restoring lost forests help slow climate change?

  3:04
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  Ultimate Crash Test: Impact Preview

  Forensic science is put to the test after the first-ever staged multi-vehicle pileup.

  0:30
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  When Machines Prescribe

  Investigate medical algorithms in which the patient’s race drives decisions.

  17:19
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  Do Plants Know Math?

  Evolution seems to favor these numbers.

  2:24
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  Ultimate Crash Test: Countdown Preview

  A first-of-its-kind experiment aims to stage a multi-vehicle pileup to gain new data on car safety.

  0:30
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  UFO Sightings: How Scientists are Trying to Capture More Data

  To better study the UFO phenomenon, science needs more eyes on the skies.

  5:00