1 00:00:00,000 --> 00:00:08,670 The space between stars holds an array of vibrant clouds. 2 00:00:08,670 --> 00:00:11,750 Clouds that command our attention. 3 00:00:11,750 --> 00:00:15,884 Clouds that create spectacular displays. 4 00:00:15,884 --> 00:00:21,896 Clouds that seem familiar, tenuous, and fragile. 5 00:00:21,896 --> 00:00:26,424 Clouds that hold clues to star birth, and death. 6 00:00:26,424 --> 00:00:32,630 NASA’s Hubble Space Telescope has imaged hundreds of them in extraordinary detail. 7 00:00:32,630 --> 00:00:37,065 These vast swirls of gas and dust get their name from the Latin word, 8 00:00:37,065 --> 00:00:40,259 nebula, meaning “cloud” or “mist." 9 00:00:40,259 --> 00:00:43,297 "Nebulae" is the plural of "Nebula," and they come 10 00:00:43,297 --> 00:00:47,908 in a wide range of shapes, sizes, and forms. 11 00:00:47,908 --> 00:00:52,150 Emission nebulae are some of the most spectacular. 12 00:00:52,150 --> 00:00:58,837 These opaque, gleaming clouds of gas and dust radiate, or emit, their own light. 13 00:00:58,837 --> 00:01:03,440 Ultraviolet light from nearby stars energizes atoms in the cloud. 14 00:01:03,440 --> 00:01:06,200 When the excited atoms lose that energy, 15 00:01:06,200 --> 00:01:09,869 they release the light that gives emission nebulae their glow. 16 00:01:09,869 --> 00:01:14,706 The Orion Nebula is one of the most famous emission nebulae. 17 00:01:14,706 --> 00:01:19,407 

Its core, called the Trapezium, holds four enormous young stars 18 00:01:19,407 --> 00:01:23,592 whose ultraviolet light powers the region’s intense glow.
 19 00:01:23,592 --> 00:01:26,310 The Carina Nebula is another vast emission 20 00:01:26,310 --> 00:01:30,233 nebula and star-forming region in our galaxy. 21 00:01:30,233 --> 00:01:35,460 Within the nebula is a pillar three light years tall, dubbed Mystic Mountain. 22 00:01:35,460 --> 00:01:41,306 It cloaks massive young stars, some with jets emerging from the cloud. 23 00:01:41,306 --> 00:01:45,420 Hubble’s infrared view cuts through the shroud of gas and dust, 24 00:01:45,420 --> 00:01:49,928 revealing these radiant jewels. 25 00:01:49,928 --> 00:01:56,506 Reflection nebulae shine by the reflected or scattered light of nearby stars. 26 00:01:56,506 --> 00:02:00,950 They often have a bluish color because the dust grains in the cloud scatter blue light 27 00:02:00,950 --> 00:02:05,389 more efficiently than red light. 28 00:02:05,389 --> 00:02:08,550 Not all nebulae shine brightly. 29 00:02:08,550 --> 00:02:14,040 Dark or absorption nebulae are inky-black clouds of gas and dust that block the light 30 00:02:14,040 --> 00:02:16,716 coming from objects behind them. 31 00:02:16,716 --> 00:02:20,742 Because they are dark, absorption nebulae are hard to find. 32 00:02:20,742 --> 00:02:27,213 We only see them as silhouettes against a much brighter region of space. 33 00:02:27,213 --> 00:02:33,237 Most large nebulae are a combination of emission, reflection, and absorption nebulae. 34 00:02:33,237 --> 00:02:36,549 Their dark dust lanes may give birth to new stars 35 00:02:36,549 --> 00:02:41,207 that provide the light needed to illuminate the cloud. 36 00:02:41,207 --> 00:02:48,509 Planetary nebulae are a type of emission nebula powered by a small to medium-sized dying star. 37 00:02:48,509 --> 00:02:54,260 
As these stars run out of fuel, they periodically blow off their outer layers. 38 00:02:54,260 --> 00:02:57,733 The expelled gas expands outward, away from the star, 39 00:02:57,733 --> 00:03:01,254 forming a bubble, or shell, around the star. 40 00:03:01,254 --> 00:03:05,281 Sometimes, the envelope of debris holds clumps of dense gas 41 00:03:05,281 --> 00:03:10,110 that shine like the gems of a necklace. 42 00:03:10,110 --> 00:03:15,910 The term “planetary nebula” is misleading. It comes from late eighteenth-century astronomers 43 00:03:15,910 --> 00:03:22,447 who thought their rounded shape looked similar to planets in telescopes of that time. 44 00:03:22,447 --> 00:03:27,202 They named them “planetary nebulae" as a result. 45 00:03:27,202 --> 00:03:31,270 Supernova remnants are the diffuse clouds of expanding debris 46 00:03:31,270 --> 00:03:35,209 released by a massive star’s death explosion. 47 00:03:35,209 --> 00:03:42,790 The Cygnus Loop is a vast, expanding 110-light year-wide supernova remnant. 48 00:03:42,790 --> 00:03:48,904 It is so large that Hubble can only image small sections of it at a time. 49 00:03:48,904 --> 00:03:54,175 Some supernova remnants emit their light from a shell of shocked material. 50 00:03:54,175 --> 00:04:00,790 Others, like the Crab Nebula, emit most of their light from within the expanding shell. 51 00:04:00,790 --> 00:04:06,549 And still other supernova remnants shine as a combination of the two. 52 00:04:06,549 --> 00:04:10,995 Nebulae are some of the most resplendent objects in the universe, 53 00:04:10,995 --> 00:04:13,186 and thanks to the Hubble Space Telescope, 54 00:04:13,186 --> 00:04:16,903 we can study them in all of their magnificent forms. 55 00:04:16,903 --> 00:04:24,130 [ MUSIC ]