Fall Asleep Learning Why the Sky Changes Colour | 1 Hour of Calm Sky Science for Sleep

Drift off to sleep on a quiet hillside on a warm summer evening, as the sky slowly turns from blue, to gold, to rose, to deep twilight blue, and finally to a starry night. Along the way we gently learn why: why the daytime sky is blue and not violet, why clouds are white and distant hills look blue, why sunsets glow orange and red, the green flash, the belt of Venus and the shadow of the Earth, the deep blue of twilight, noctilucent clouds, rainbows, glories, halos and sun dogs, the blue sunsets of Mars, the orange haze of Titan, airglow, and the Milky Way. A calm, slow narration over a soft, generated breeze. No music, no ads in the middle, nothing sudden. You do not need to follow along. If you drift off halfway, that is the whole idea. Chapters 0:00 Settling in on the hillside 4:17 Why the sky is blue 12:38 White clouds and blue hills 17:45 Golden hour and sunset 24:09 Rays, the belt of Venus and the Earth's shadow 27:07 Twilight and the blue hour 35:30 Rainbows, glories, halos and sun dogs 44:53 Skies on other worlds 48:55 Airglow, moonlight and the Milky Way 52:39 Night over the hillside Image credits Sunset over a hillside, Teignbridge, and grassy hillsides at sunset, West Somerset: Lewis Clarke (CC BY-SA 2.0) Mist in the valley below: Jeff Buck (CC BY-SA 2.0) Mountain lake and a clear blue sky: AS Photography from Poland (CC BY 4.0) Blue sky with wisps of cloud on a clear summer morning: Tom Axford (CC BY-SA 4.0) Small white cumulus clouds in the blue sky: Aleda12 (CC BY-SA 4.0) Cirrus uncinus clouds in the morning sky: ADARSHluck (CC BY-SA 4.0) Cumulus and cirrostratus over Gåseberg, strong pink belt of Venus over Brastad: W.carter (CC BY-SA 4.0) Clouds over Brofjorden at blue hour: W.carter (CC0) Sunset from the International Space Station: NASA, ISS Expedition 23 crew (public domain) Earthrise, Apollo 8: NASA (public domain) White cumulus clouds against blue sky: Lance Vanlewen (CC BY-SA 4.0) Dark clouds above a hilly valley: LoboStudio Hamburg (CC0) View from the Blue Ridge Parkway: DiscoA340 (CC BY-SA 4.0) Sunny mist in the mountains at golden hour, Vang Vieng, Laos: Basile Morin (CC BY-SA 4.0) Sunset over Criffel: James Johnstone (CC BY 2.0) Sunset after the eruption of Mount Pinatubo, 1991: CSIRO Atmospheric Research (CC BY 3.0) Sunset over the sea from Llanddwyn Island, Anglesey: TXGemGem (CC BY-SA 4.0) Green flash, and sunset clouds and crepuscular rays over the Pacific: Brocken Inaglory (CC BY-SA 3.0) Sunset over the sea in Flø: Janko Ferlič (CC0) Noctilucent clouds over Slovakia: Chmee2 (CC BY-SA 4.0) Crescent Moon and evening star over Dünsberg: LudwigSebastianMicheler (CC BY-SA 4.0) Double rainbow: John Fowler (CC BY 2.0) Double rainbow with Alexander's band: Olga Aleksandra (CC BY 4.0) Fogbow at Udukaar: Heidi Võsu (CC0) Fogbow, Brocken spectre and glory, Hinlopen Strait, Svalbard: Andreas Weith (CC BY-SA 4.0) Halo over Großkrotzenburg: Patrick Looß (CC BY-SA 4.0) Parhelia on a sunny Arctic morning, Svalbard: AWeith (CC BY-SA 4.0) Sun pillar at sunrise: Arvis Gedušs (CC BY 2.0) Cloud iridescence and crepuscular rays: Gursach44 (CC BY-SA 4.0) Milky Way over the valley of the Marukha River, Arkhyz: Alexander Kurilov (CC BY 4.0) Sunset in Gale Crater, Mars: NASA/JPL-Caltech/MSSS/Texas A&M Univ. (public domain) Titan, with the rings of Saturn: NASA/JPL-Caltech/Space Science Institute (public domain) Airglow over La Silla: P. Horálek/ESO (CC BY 4.0) Aurora over Levi, Lapland: Ximonic (Simo Räsänen) (CC BY-SA 4.0) Moonlit reflections: Derk29 (CC BY-SA 4.0) Milky Way over Llyn Ogwen: John Badham (CC BY-SA 4.0) Big Meadows starry sky: Shenandoah National Park, NPS (public domain) Cottage at night in Nuthurst, West Sussex: Acabashi (CC BY-SA 4.0) Night lights and airglow seen from the International Space Station: NASA, Expedition 30 crew (public domain) Images from Wikimedia Commons and the NASA Image and Video Library. Photographs are cropped to fit the frame. Narration voice generated with Amazon Polly. Ambient sound generated for this video. This video is not affiliated with or endorsed by NASA, ESO, CSIRO or the National Park Service.