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How Earth’s Climate Changed Over the Past 500 Million Years

Over its history, Earth has fluctuated between two climate states: Icehouses, with ice caps at at least one of the poles, and Hothouses, when there is no ice at the poles.
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Clip Season 47 Episode 1 Length 03:25 Premiere: 02/05/20

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Season 47 Episodes

Cat Tales
S47 E3 Length 53:21 Premiere Date 02/19/20

Polar Extremes
S47 E1 Length 1:52:46 Premiere Date 02/05/20

Polar Extremes Preview
Preview Length 03:19 Premiere Date 02/05/20

What if Carbon Left Your Tailpipe as Solid Chunks?
Clip Length 02:12 Premiere Date 02/05/20

Plant Fossils Hint at Arctic's Swampy Past
Clip Length 03:02 Premiere Date 02/05/20

What did the East Coast Look Like 3 Million Years Ago?
Clip Length 03:21 Premiere Date 02/05/20

How Carbon Dioxide Warms Planet Earth
Clip Length 02:32 Premiere Date 02/05/20

A Bird's-Eye View of Carbon Emissions
Clip Length 01:56 Premiere Date 02/05/20

This Alaska Community is Losing Sea Ice to Climate Change
Clip Length 04:47 Premiere Date 02/05/20

Fifty Million Years Ago, the Arctic Was a Warm Swamp
Clip Length 02:07 Premiere Date 02/05/20

What’s Causing Greenland’s Biggest Glacier to Melt?
Clip Length 02:04 Premiere Date 02/05/20

How Earth’s Climate Changed Over the Past 500 Million Years
Clip Length 03:25 Premiere Date 02/05/20

This Canadian Cave Has Been Frozen Since the Last Ice Age
Clip Length 03:11 Premiere Date 02/05/20

How Climate Has Shifted Over Millions of Years
Clip Length 02:44 Premiere Date 02/05/20

Why Trees Are Living Climate Records
Clip Length 01:29 Premiere Date 02/03/20

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Evolution: On the Run - S53 E17

An evolutionary ride from early aquatic ancestors to highly optimized runners like the horse.

  • Sunday November 15, 2026 7:00 pm ET on KET2
  • Sunday November 15, 2026 6:00 pm CT on KET2
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NOVA Universe Revealed: Age of Stars - S48 E15

Premiered On: 10/27/2021

The Hubble Space Telescope and a heat-resistant solar probe reveal new clues about the sun's 5-billion-year history.

  • Monday November 16, 2026 5:00 pm ET on KET
  • Monday November 16, 2026 4:00 pm CT on KET

NOVA Universe Revealed: Milky Way - S48 E16

Premiered On: 11/03/2021

Explore the history of the Milky Way, including what shaped this spiral of stars, gas and dust and what its destiny will be.

  • Tuesday November 17, 2026 5:00 pm ET on KET
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NOVA Universe Revealed: Alien Worlds - S48 E17

Premiered On: 11/10/2021

New science and discoveries made possible by ultra-sensitive telescopes and detective work transform alien planet-hunting from science fiction into fact.

  • Wednesday November 18, 2026 5:00 pm ET on KET
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NOVA Universe Revealed: Black Holes - S48 E18

Premiered On: 11/17/2021

A new generation of high-powered telescopes brings black holes to light. Animation reveals what happens when objects stray too close to a black hole's point of no return.

  • Thursday November 19, 2026 5:00 pm ET on KET
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NOVA Universe Revealed: Big Bang - S48 E19

Premiered On: 11/24/2021

Nova probes the mystery of the Big Bang with stunning animation based on space telescope images.

  • Friday November 20, 2026 5:00 pm ET on KET
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Secrets in Your Data - S51 E7

Alok Patel takes a look at what happens to the personal data shared on social media and efforts to maximize benefits without compromising personal privacy.

  • Sunday November 22, 2026 7:00 pm ET on KET2
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Decoding da Vinci - S46 E21

Premiered On: 11/13/2019

Discover how Leonardo da Vinci used science, from human dissections to innovative painting techniques, to create his legendary artwork. Learn why Mona Lisa's smile is so captivating - and what it took to create it.

  • Wednesday November 25, 2026 9:00 pm ET on KET
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The Planets: Saturn - S46 E15

Premiered On: 08/07/2019

NASA's Cassini probe explores Saturn's icy rings and moons, capturing ring-moon interactions and revealing ingredients for life on the moon Enceladus.

  • Thursday December 3, 2026 4:30 pm ET on KET
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Can Dogs Talk? - S53 E3

Scientists conduct the largest animal communication study in history to see if innovative word buttons truly enable dogs to talk.

  • Wednesday December 9, 2026 9:00 pm ET on KET
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Evolution: On the Run - S53 E17

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Evolution: The Mating Game - S53 E16

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Evolution: Body Builders - S53 E15

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Evolution: Need to Feed - S53 E14

  • Wednesday October 28, 2026 8:00 am ET on KETWORLD
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Evolution: Brain Power - S53 E13

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Space Wars - S53 E12

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