1 00:00:03,400 --> 00:00:08,039 Speaker 1: Welcome to brain Stuff production of I Heart Radio. Hi 2 00:00:08,160 --> 00:00:10,920 Speaker 1: brain Stuff. I'm Lauren vogel Bom and this is another 3 00:00:11,000 --> 00:00:15,040 Speaker 1: classic episode. In this one, we dip into the everyday 4 00:00:15,040 --> 00:00:18,439 Speaker 1: science of why the stars and our skies, most of 5 00:00:18,440 --> 00:00:25,119 Speaker 1: which emit fairly constant light, appear to twinkle. Hey, brain Stuff, 6 00:00:25,160 --> 00:00:28,880 Speaker 1: Lauren Vogel bomb Here. All things considered, our atmosphere is 7 00:00:28,960 --> 00:00:33,040 Speaker 1: pretty great. This blanket of nitrogen, oxygen, and other gases 8 00:00:33,159 --> 00:00:36,519 Speaker 1: keeps the world's temperature nice and habitable while protecting us 9 00:00:36,600 --> 00:00:39,280 Speaker 1: from harmful U V radiation, to say nothing of this 10 00:00:39,360 --> 00:00:42,680 Speaker 1: space debris it vaporizes for us. Oh yeah, and without 11 00:00:42,680 --> 00:00:45,839 Speaker 1: all that oxygen in our atmosphere, animal life couldn't survive 12 00:00:45,920 --> 00:00:49,879 Speaker 1: on planet Earth. Not a bad resume. But despite its 13 00:00:49,920 --> 00:00:52,920 Speaker 1: many good qualities, the atmosphere can be a nuisance to 14 00:00:53,000 --> 00:00:57,520 Speaker 1: astronomy buffs. That's because it distorts light. At night, the 15 00:00:57,600 --> 00:01:01,120 Speaker 1: atmosphere makes some heavenly bodies appear to flicker and shimmer. 16 00:01:01,480 --> 00:01:05,640 Speaker 1: The technical term for this phenomenon is astronomical scintillation. You 17 00:01:05,800 --> 00:01:09,520 Speaker 1: probably know it by a different name, twinkling like an onion. 18 00:01:09,640 --> 00:01:12,560 Speaker 1: The atmosphere is made up of layers. At the bottom 19 00:01:12,640 --> 00:01:15,640 Speaker 1: is the troposphere, which starts right here at ground level 20 00:01:15,680 --> 00:01:19,000 Speaker 1: on the planet's surface, standing about five to nine miles 21 00:01:19,000 --> 00:01:22,399 Speaker 1: that's eight to four point five kilometers tall. It's where 22 00:01:22,480 --> 00:01:25,840 Speaker 1: most of Earth's weather events take place. The other layers 23 00:01:25,880 --> 00:01:31,400 Speaker 1: are in ascending order, the stratosphere, mesosphere, thermosphere, and exosphere. 24 00:01:31,760 --> 00:01:34,920 Speaker 1: There's also a region called the ionosphere, which encompasses parts 25 00:01:34,920 --> 00:01:39,160 Speaker 1: of both the mesosphere and the thermosphere. These layers have 26 00:01:39,360 --> 00:01:43,679 Speaker 1: different temperatures. In addition, the air's density varies from level 27 00:01:43,680 --> 00:01:47,240 Speaker 1: to level. When starlight enters our atmosphere, it runs into 28 00:01:47,280 --> 00:01:50,800 Speaker 1: pockets of cool and warm air. The pockets act as 29 00:01:50,840 --> 00:01:54,480 Speaker 1: big lenses, causing the light to change direction or refract 30 00:01:54,720 --> 00:01:57,480 Speaker 1: as it passes through them. Yet the lenses are not 31 00:01:57,640 --> 00:02:01,400 Speaker 1: fixed in place. They move around in a shape as 32 00:02:01,440 --> 00:02:05,320 Speaker 1: they shift. So does starlight refraction. That's why the stars 33 00:02:05,360 --> 00:02:10,880 Speaker 1: appear to twinkle. Scintillation affects planets to Mercury, Venus, Mars, 34 00:02:10,960 --> 00:02:13,639 Speaker 1: and the other planets in our Solar system do twinkle 35 00:02:13,720 --> 00:02:16,400 Speaker 1: when viewed from Earth on a clear night. So does 36 00:02:16,400 --> 00:02:20,440 Speaker 1: our moon. However, the planets twinkled to a barely noticeable 37 00:02:20,480 --> 00:02:25,040 Speaker 1: degree distance is the main reason stars twinkle. More conspicuously 38 00:02:25,120 --> 00:02:28,200 Speaker 1: than the planets in our Solar system. Because the former 39 00:02:28,280 --> 00:02:31,360 Speaker 1: are so far away, each star looks like a single 40 00:02:31,520 --> 00:02:35,079 Speaker 1: pinpoint of light, a single pixel. You might say. It's 41 00:02:35,080 --> 00:02:38,200 Speaker 1: a different story for Earth's moon and our neighboring planets, 42 00:02:38,680 --> 00:02:41,960 Speaker 1: being a lot closer, they are less affected by the atmosphere. 43 00:02:42,360 --> 00:02:45,000 Speaker 1: Planets and moons appear as tiny disks up in the sky. 44 00:02:45,560 --> 00:02:47,680 Speaker 1: The light they emanate comes not from a single point, 45 00:02:47,800 --> 00:02:52,040 Speaker 1: but from many individual points, all clustered together. These rarely 46 00:02:52,080 --> 00:02:55,119 Speaker 1: scintillate in unison, which is why planets and moons don't 47 00:02:55,160 --> 00:02:59,480 Speaker 1: twinkle as dramatically as the stars. So twinkling can only 48 00:02:59,520 --> 00:03:02,600 Speaker 1: happen an atmosphere is present. It's for this reason that 49 00:03:02,680 --> 00:03:05,639 Speaker 1: photos taken by the Hubble telescope looks so clear. There 50 00:03:05,680 --> 00:03:09,679 Speaker 1: aren't any atmospheric air pockets to refract the starlight. Earthbound 51 00:03:09,680 --> 00:03:14,000 Speaker 1: astronomers use telescopes with adaptive optics systems to compensate for twinkling, 52 00:03:14,200 --> 00:03:21,800 Speaker 1: making the stars look more stable. Today's episode is based 53 00:03:21,840 --> 00:03:24,200 Speaker 1: on the article why do stars Twinkle? On how stuff 54 00:03:24,200 --> 00:03:27,239 Speaker 1: works dot com, written by Mark Mancini. Brain Stuff is 55 00:03:27,280 --> 00:03:29,600 Speaker 1: production of by Heart Radio in partnership with how Stuff Works. 56 00:03:29,600 --> 00:03:31,480 Speaker 1: Dot com and it is produced by Tyler Clang with 57 00:03:31,480 --> 00:03:34,920 Speaker 1: assistance from Ramsey Young. For more podcasts from My Heart Radio, 58 00:03:35,040 --> 00:03:37,680 Speaker 1: visit the air heart Radio app, Apple Podcasts, or wherever 59 00:03:37,720 --> 00:03:39,080 Speaker 1: you listen into your favorite shows.