[Script Info]
Title: 
[Events]
Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text
Dialogue: 0,0:00:09.22,0:00:12.55,Default,,0000,0000,0000,,This is the Microraptor,
Dialogue: 0,0:00:12.55,0:00:17.06,Default,,0000,0000,0000,,a carnivorous four-winged dinosaur\Nthat was almost two feet long,
Dialogue: 0,0:00:17.06,0:00:18.27,Default,,0000,0000,0000,,ate fish,
Dialogue: 0,0:00:18.27,0:00:21.21,Default,,0000,0000,0000,,and lived about 120 million years ago.
Dialogue: 0,0:00:21.21,0:00:26.18,Default,,0000,0000,0000,,Most of what we know about it\Ncomes from fossils that look like this.
Dialogue: 0,0:00:26.18,0:00:29.97,Default,,0000,0000,0000,,So, is its coloration here \Njust an artist's best guess?
Dialogue: 0,0:00:29.97,0:00:32.29,Default,,0000,0000,0000,,The answer is no.
Dialogue: 0,0:00:32.29,0:00:35.41,Default,,0000,0000,0000,,We know this shimmering \Nblack color is accurate
Dialogue: 0,0:00:35.41,0:00:40.61,Default,,0000,0000,0000,,because paleontologists have analyzed\Nclues contained within the fossil.
Dialogue: 0,0:00:40.61,0:00:44.83,Default,,0000,0000,0000,,But making sense of the evidence\Nrequires careful examination of the fossil
Dialogue: 0,0:00:44.83,0:00:50.03,Default,,0000,0000,0000,,and a good understanding of the physics\Nof light and color.
Dialogue: 0,0:00:50.03,0:00:53.69,Default,,0000,0000,0000,,First of all, here's what we actually see\Non the fossil:
Dialogue: 0,0:00:53.69,0:00:58.39,Default,,0000,0000,0000,,imprints of bones and feathers that have\Nleft telltale mineral deposits.
Dialogue: 0,0:00:58.39,0:00:59.83,Default,,0000,0000,0000,,And from those imprints,
Dialogue: 0,0:00:59.83,0:01:02.44,Default,,0000,0000,0000,,we can determine that these \NMicroraptor feathers
Dialogue: 0,0:01:02.44,0:01:07.57,Default,,0000,0000,0000,,were similar to modern dinosaur,\Nas in bird, feathers.
Dialogue: 0,0:01:07.57,0:01:11.24,Default,,0000,0000,0000,,But what gives birds their signature\Ndiverse colorations?
Dialogue: 0,0:01:11.24,0:01:15.83,Default,,0000,0000,0000,,Most feathers contain just one\Nor two dye-like pigments.
Dialogue: 0,0:01:15.83,0:01:18.40,Default,,0000,0000,0000,,The cardinal's bright red\Ncomes from carotenoids,
Dialogue: 0,0:01:18.40,0:01:21.41,Default,,0000,0000,0000,,the same pigments \Nthat make carrots orange,
Dialogue: 0,0:01:21.41,0:01:23.74,Default,,0000,0000,0000,,while the black of its face\Nis from melanin,
Dialogue: 0,0:01:23.74,0:01:27.03,Default,,0000,0000,0000,,the pigment that colors our hair and skin.
Dialogue: 0,0:01:27.03,0:01:30.46,Default,,0000,0000,0000,,But in bird feathers,\Nmelanin isn't simply a dye.
Dialogue: 0,0:01:30.46,0:01:34.15,Default,,0000,0000,0000,,It forms hollow nanostructures\Ncalled melanosomes
Dialogue: 0,0:01:34.15,0:01:37.27,Default,,0000,0000,0000,,which can shine in all the colors\Nof the rainbow.
Dialogue: 0,0:01:37.27,0:01:39.19,Default,,0000,0000,0000,,To understand how that works,
Dialogue: 0,0:01:39.19,0:01:41.67,Default,,0000,0000,0000,,it helps to remember \Nsome things about light.
Dialogue: 0,0:01:41.67,0:01:46.94,Default,,0000,0000,0000,,Light is basically a tiny electromagnetic\Nwave traveling through space.
Dialogue: 0,0:01:46.94,0:01:49.32,Default,,0000,0000,0000,,The top of a wave is called its crest
Dialogue: 0,0:01:49.32,0:01:53.48,Default,,0000,0000,0000,,and the distance between two crests\Nis called the wavelength.
Dialogue: 0,0:01:53.48,0:01:58.24,Default,,0000,0000,0000,,The crests in red light are about\N700 billionths of a meter apart
Dialogue: 0,0:01:58.24,0:02:01.48,Default,,0000,0000,0000,,and the wavelength of purple light\Nis even shorter,
Dialogue: 0,0:02:01.48,0:02:06.16,Default,,0000,0000,0000,,about 400 billionths of a meter,\Nor 400 nanometers.
Dialogue: 0,0:02:06.16,0:02:10.24,Default,,0000,0000,0000,,When light hits the thin front surface\Nof a bird's hollow melanosome,
Dialogue: 0,0:02:10.24,0:02:13.75,Default,,0000,0000,0000,,some is reflected and some passes through.
Dialogue: 0,0:02:13.75,0:02:18.11,Default,,0000,0000,0000,,A portion of the transmitted light\Nthen reflects off the back surface.
Dialogue: 0,0:02:18.11,0:02:20.55,Default,,0000,0000,0000,,The two reflected waves interact.
Dialogue: 0,0:02:20.55,0:02:22.49,Default,,0000,0000,0000,,Usually they cancel each other out,
Dialogue: 0,0:02:22.49,0:02:24.67,Default,,0000,0000,0000,,but when the wavelength\Nof the reflected light
Dialogue: 0,0:02:24.67,0:02:27.84,Default,,0000,0000,0000,,matches the distance between\Nthe two reflections,
Dialogue: 0,0:02:27.84,0:02:29.76,Default,,0000,0000,0000,,they reinforce each other.
Dialogue: 0,0:02:29.76,0:02:33.04,Default,,0000,0000,0000,,Green light has a wavelength\Nof about 500 nanometers,
Dialogue: 0,0:02:33.04,0:02:36.33,Default,,0000,0000,0000,,so melanosomes that are \Nabout 500 nanometers across
Dialogue: 0,0:02:36.33,0:02:38.28,Default,,0000,0000,0000,,give off green light,
Dialogue: 0,0:02:38.28,0:02:40.76,Default,,0000,0000,0000,,thinner melanosomes give off purple light,
Dialogue: 0,0:02:40.76,0:02:43.55,Default,,0000,0000,0000,,and thicker ones give off red light.
Dialogue: 0,0:02:43.55,0:02:45.99,Default,,0000,0000,0000,,Of course, it's more complex than this.
Dialogue: 0,0:02:45.99,0:02:49.71,Default,,0000,0000,0000,,The melanosomes are packed together\Ninside cells, and other factors,
Dialogue: 0,0:02:49.71,0:02:54.37,Default,,0000,0000,0000,,like how the melanosomes are arranged \Nwithin the feather, also matter.
Dialogue: 0,0:02:54.37,0:02:56.82,Default,,0000,0000,0000,,Let's return to the Microraptor fossil.
Dialogue: 0,0:02:56.82,0:03:01.03,Default,,0000,0000,0000,,When scientists examined its feather \Nimprints under a powerful microscope,
Dialogue: 0,0:03:01.03,0:03:04.31,Default,,0000,0000,0000,,they found nanostructures \Nthat look like melanosomes.
Dialogue: 0,0:03:04.31,0:03:09.16,Default,,0000,0000,0000,,X-ray analysis of the melanosomes\Nfurther supported that theory.
Dialogue: 0,0:03:09.16,0:03:13.38,Default,,0000,0000,0000,,They contained minerals that would\Nresult from the decay of melanin.
Dialogue: 0,0:03:13.38,0:03:16.78,Default,,0000,0000,0000,,The scientists then chose 20 feathers\Nfrom one fossil
Dialogue: 0,0:03:16.78,0:03:20.96,Default,,0000,0000,0000,,and found that \Nthe melanosomes in all 20 looked alike,
Dialogue: 0,0:03:20.96,0:03:25.04,Default,,0000,0000,0000,,so they became pretty sure this dinosaur\Nwas one solid color.
Dialogue: 0,0:03:25.04,0:03:29.37,Default,,0000,0000,0000,,They compared these Microraptor\Nmelanosomes to those of modern birds
Dialogue: 0,0:03:29.37,0:03:32.94,Default,,0000,0000,0000,,and found a close similarity,\Nthough not a perfect match,
Dialogue: 0,0:03:32.94,0:03:37.12,Default,,0000,0000,0000,,to the iridescent teal feathers\Nfound on duck wings.
Dialogue: 0,0:03:37.12,0:03:40.100,Default,,0000,0000,0000,,And by examining the exact size\Nand arrangement of the melanosomes,
Dialogue: 0,0:03:40.100,0:03:45.88,Default,,0000,0000,0000,,scientists determined that the feathers\Nwere iridescent black.
Dialogue: 0,0:03:45.88,0:03:48.90,Default,,0000,0000,0000,,Now that we can determine\Na fossilized feather's color,
Dialogue: 0,0:03:48.90,0:03:54.06,Default,,0000,0000,0000,,paleontologists are looking for more\Nfossils with well-preserved melanosomes.
Dialogue: 0,0:03:54.06,0:03:57.85,Default,,0000,0000,0000,,They've found that a lot of dinosaurs,\Nincluding Velociraptor,
Dialogue: 0,0:03:57.85,0:03:59.52,Default,,0000,0000,0000,,probably had feathers,
Dialogue: 0,0:03:59.52,0:04:04.86,Default,,0000,0000,0000,,meaning that certain films might not be\Nso biologically accurate.
Dialogue: 0,0:04:04.86,0:04:06.56,Default,,0000,0000,0000,,Clever girls.