WEBVTT 00:21.121 --> 00:23.123 align:left position:35% line:89% size:55% Star Colors! 00:23.223 --> 00:29.629 align:left position:77.5% line:83% size:12.5% Our closest star, the sun, is a miasma of incandescent plasma -- superheated gas shining 00:29.729 --> 00:32.365 align:left position:82.5% line:89% size:7.5% out into our solar system and beyond. 00:32.465 --> 00:36.669 align:left position:77.5% line:83% size:12.5% If an extraterrestrial being looked up at their night sky and spotted our star, they d 00:36.770 --> 00:38.204 align:left position:27.5% line:89% size:62.5% see a white speck. 00:38.304 --> 00:40.006 align:left position:85% line:89% size:5% But Trace, you might be thinking. 00:40.106 --> 00:42.942 align:left position:80% line:83% size:10% The sun is sometimes yellow, or orange or red! 00:43.043 --> 00:44.811 align:left position:10% line:89% size:80% And this is true, lovely viewer! 00:44.911 --> 00:50.750 align:left position:77.5% line:83% size:12.5% The sun can APPEAR to be those colors, but that s mainly an illusion due to our atmosphere. 00:50.850 --> 00:55.789 align:left position:70% line:83% size:20% Astronauts see the sun as a bright white source of our heat and light. 00:55.889 --> 01:00.794 align:left position:80% line:83% size:10% When you look up at the night sky, it s hard to miss all those white specks of starlight, 01:00.894 --> 01:05.698 align:left position:77.5% line:83% size:12.5% but if you look closer, you ll notice that not all the stars ARE white -- some are red, 01:05.799 --> 01:09.102 align:left position:12.5% line:89% size:77.5% orange, yellow, and even blue! 01:09.202 --> 01:12.505 align:left position:77.5% line:83% size:12.5% Because of Orion s position in the sky it is one of the most loved winter constellations, 01:12.605 --> 01:16.076 align:left position:70% line:83% size:20% but it can be visible very early in the morning at other times of year. 01:16.176 --> 01:21.748 align:left position:77.5% line:83% size:12.5% Regardless, next time you see The Hunter, look closely at the two brightest stars, and 01:21.848 --> 01:25.518 align:left position:77.5% line:83% size:12.5% you ll notice the top left star, his right shoulder, is RED. 01:25.618 --> 01:28.922 align:left position:77.5% line:89% size:12.5% That s Betelgeuse, a dying red giant star. 01:29.022 --> 01:32.125 align:left position:80% line:83% size:10% It s cooler than our sun, which means it burns redder. 01:32.225 --> 01:35.328 align:left position:77.5% line:83% size:12.5% Red Giants are stars that are nearing the end of their lives. 01:35.428 --> 01:38.098 align:left position:75% line:83% size:15% At that point they start to expand and cool off 01:38.198 --> 01:42.802 align:left position:75% line:83% size:15% Betelgeuse varies between 500 and 900 times larger than our star! 01:42.902 --> 01:47.907 align:left position:72.5% line:83% size:17.5% If it were sitting where our sun is now, we d be inside B s surface. 01:48.007 --> 01:53.346 align:left position:72.5% line:83% size:17.5% But, tucking back out to all of Orion -- shift to the bottom right side of the constellation, 01:53.446 --> 01:57.984 align:left position:82.5% line:83% size:7.5% Orion s left foot -- that s Rigel, and if you really look, you might notice that 01:58.084 --> 01:59.586 align:left position:37.5% line:89% size:52.5% it s BLUE. 01:59.686 --> 02:02.455 align:left position:77.5% line:83% size:12.5% Rigel is a blue supergiant star and one of the brightest in the night sky. 02:02.555 --> 02:08.027 align:left position:75% line:83% size:15% Rigel is 70 times larger in diameter, 40,000 times brighter, and twice as hot as our own 02:08.128 --> 02:09.696 align:left position:45% line:89% size:45% sun. 02:09.796 --> 02:12.599 align:left position:72.5% line:83% size:17.5% If we were orbiting Rigel at the same distance as we do our sun, we d burn up! 02:12.699 --> 02:16.436 align:left position:75% line:83% size:15% To have comfortable temperatures like we do now, we d have to be five times further 02:16.536 --> 02:19.906 align:left position:75% line:89% size:15% away from Rigel than Pluto is from the sun. 02:20.006 --> 02:22.709 align:left position:32.5% line:89% size:57.5% That s so far! 02:22.809 --> 02:24.611 align:left position:12.5% line:89% size:77.5% Star colors aren t arbitrary. 02:24.711 --> 02:29.015 align:left position:75% line:83% size:15% The color of a star has to do with what it s burning and its surface temperature. 02:29.115 --> 02:32.986 align:left position:77.5% line:83% size:12.5% Cooler stars are redder, hotter stars are bluer -- this is the opposite of how your 02:33.086 --> 02:35.922 align:left position:82.5% line:89% size:7.5% faucets work at home... because fire. 02:36.022 --> 02:39.425 align:left position:77.5% line:83% size:12.5% Instead, think about the flame of a Bunsen burner in science class! 02:39.526 --> 02:43.463 align:left position:70% line:89% size:20% Blue flames are hottest, red flames are cooler. 02:43.563 --> 02:50.770 align:left position:77.5% line:83% size:12.5% Our sun shines at about 6,000 Kelvin, but Betelgeuse is a cool 3,000 Kelvin, and Rigel 02:50.870 --> 02:53.273 align:left position:17.5% line:89% size:72.5% is a spicy 11,000 Kelvin. 02:53.373 --> 02:56.776 align:left position:70% line:83% size:20% The closer you look at the sky, the more colors you ll see! 02:56.876 --> 03:01.814 align:left position:72.5% line:83% size:17.5% Look for Spica, Vega, Alpheratz, and Bellatrix for more blue stars and remember that means 03:01.915 --> 03:03.683 align:left position:30% line:89% size:60% they are hotter. 03:03.783 --> 03:07.754 align:left position:77.5% line:83% size:12.5% Then look for Mirach, Antares, Aldebaran, and Arcturus for spectacular red stars -- and 03:07.854 --> 03:10.890 align:left position:15% line:89% size:75% remember, those are cooler. 03:10.990 --> 03:14.794 align:left position:77.5% line:83% size:12.5% Stars are incredible things, and there are many reasons to be captivated by them, other 03:14.894 --> 03:16.663 align:left position:27.5% line:89% size:62.5% than their shine. 03:16.763 --> 03:21.134 align:left position:75% line:83% size:15% Just like living things stars are born, they age, have complex lives, and eventually they 03:21.234 --> 03:25.705 align:left position:77.5% line:83% size:12.5% die -- but throughout their lives they are all varied and unique. 03:25.805 --> 03:30.109 align:left position:67.5% line:83% size:22.5% Colors are one of many characteristics astronomers can use to learn more about these incredible, 03:30.210 --> 03:35.148 align:left position:80% line:83% size:10% massive balls of fusion, and now you ve got one more tool in you astronomical tool 03:35.248 --> 03:36.149 align:left position:42.5% line:89% size:47.5% belt. 03:36.249 --> 03:40.249 align:left position:30% line:89% size:60% Keep looking up.