WEBVTT - Why Does the Sun Get Colder Closer to Its Surface?

0:00:01.920 --> 0:00:06.720
<v Speaker 1>Welcome to brain Stuff production of I Heart Radio. Hey,

0:00:06.800 --> 0:00:10.319
<v Speaker 1>brain Stuff, learn volga about here. One of the weird

0:00:10.400 --> 0:00:13.480
<v Speaker 1>things about space is that things don't always conform to

0:00:13.520 --> 0:00:17.240
<v Speaker 1>what would seem like common sense. Take the Sun, for example.

0:00:17.800 --> 0:00:20.560
<v Speaker 1>You think that the Sun's surface would be hotter than

0:00:20.600 --> 0:00:23.599
<v Speaker 1>its outer atmosphere since the surface is closer to the

0:00:23.680 --> 0:00:26.840
<v Speaker 1>nuclear furnace at the Sun's core. After all, when you're

0:00:26.880 --> 0:00:29.560
<v Speaker 1>sitting in front of a fireplace, it feels hotter when

0:00:29.600 --> 0:00:33.360
<v Speaker 1>you get closer to it. Right. The problem is the

0:00:33.400 --> 0:00:37.040
<v Speaker 1>Sun doesn't work that way. Let's talk about the structure

0:00:37.080 --> 0:00:40.600
<v Speaker 1>of the Sun. It is composed of plasma. It has

0:00:40.720 --> 0:00:44.920
<v Speaker 1>no solid surface. However, it still has a defined structure.

0:00:45.840 --> 0:00:48.120
<v Speaker 1>The innermost part of the Sun is called the core.

0:00:48.600 --> 0:00:51.920
<v Speaker 1>This is where gravity causes enough pressure to create the

0:00:52.000 --> 0:00:56.360
<v Speaker 1>nuclear fusion of hydrogen atoms, creating atoms of helium, plus

0:00:56.400 --> 0:00:59.160
<v Speaker 1>a burst of energy that's emitted as various forms of

0:00:59.200 --> 0:01:04.200
<v Speaker 1>electromagnetic radiation of everything from ultraviolet light and X rays

0:01:04.280 --> 0:01:08.080
<v Speaker 1>too visible and infrared light, to microwaves and radio waves.

0:01:09.000 --> 0:01:13.000
<v Speaker 1>That energy slowly moves out through two layers that surround

0:01:13.080 --> 0:01:16.759
<v Speaker 1>the core, called the radiative zone and the convective zone.

0:01:17.280 --> 0:01:20.440
<v Speaker 1>Until the energy hits the photosphere, which is the part

0:01:20.440 --> 0:01:23.120
<v Speaker 1>of the Sun that we can see, and that's often

0:01:23.200 --> 0:01:26.959
<v Speaker 1>referred to as the surface of the Sun. Above that,

0:01:27.040 --> 0:01:30.400
<v Speaker 1>you've got a couple layers of atmosphere, first the chromosphere

0:01:30.600 --> 0:01:34.600
<v Speaker 1>and then the corona. Now, the weird thing that we're

0:01:34.600 --> 0:01:37.760
<v Speaker 1>talking about today is that as you progress from the

0:01:37.840 --> 0:01:41.080
<v Speaker 1>core through to the photosphere, the layers of the sun

0:01:41.120 --> 0:01:43.560
<v Speaker 1>get colder, but then as you go through the outer

0:01:43.640 --> 0:01:47.160
<v Speaker 1>atmospheric layers they get hotter. Again. Of course, this is

0:01:47.200 --> 0:01:52.240
<v Speaker 1>all relative. The photosphere is indeed pretty hot, between six thousand,

0:01:52.440 --> 0:01:56.440
<v Speaker 1>seven hundred and eleven thousand degrees fahrenheit, which is some

0:01:56.720 --> 0:02:00.560
<v Speaker 1>three thousand, seven hundred to six thousand, two hundred degrees elseus,

0:02:00.880 --> 0:02:04.360
<v Speaker 1>which is hot. But the further you get from the

0:02:04.400 --> 0:02:08.280
<v Speaker 1>Sun's surface, the hotter the atmosphere seems to get. The

0:02:08.320 --> 0:02:12.440
<v Speaker 1>temperature more than doubles through the chromosphere, and at the corona,

0:02:12.600 --> 0:02:15.160
<v Speaker 1>which is about one thousand, two hundred miles or two

0:02:15.200 --> 0:02:18.880
<v Speaker 1>thousand one kilometers from the surface, its soars to an

0:02:18.880 --> 0:02:23.600
<v Speaker 1>astonishing nine hundred thousand degrees fahrenheit or five hundred thousand

0:02:23.639 --> 0:02:29.200
<v Speaker 1>degrees celsius. Besides the Sun, some other stars also exhibit

0:02:29.240 --> 0:02:33.320
<v Speaker 1>this curious pattern, and for a long time, scientists struggled

0:02:33.320 --> 0:02:37.480
<v Speaker 1>to figure out why. They developed a hypothesis that magneto

0:02:37.600 --> 0:02:42.639
<v Speaker 1>hydrodynamic waves distribute energy from below the photosphere directly up

0:02:42.680 --> 0:02:45.760
<v Speaker 1>to the corona, almost like an express train with no

0:02:45.880 --> 0:02:52.040
<v Speaker 1>local stops. Magneto hydrodynamics combines the studies of magnetic fields

0:02:52.080 --> 0:02:56.040
<v Speaker 1>and fluids that conduct electricity. The plasma that makes up

0:02:56.040 --> 0:02:58.919
<v Speaker 1>the Sun is an extreme example of such a fluid.

0:03:00.400 --> 0:03:05.320
<v Speaker 1>In British researchers used advances and imaging technology to investigate

0:03:05.360 --> 0:03:08.600
<v Speaker 1>the Sun's chromosphere, that layer in between the photosphere and

0:03:08.639 --> 0:03:13.120
<v Speaker 1>the corona and actually examine some of these magneto hydrodynamic waves.

0:03:13.480 --> 0:03:17.160
<v Speaker 1>Their calculations confirmed that the waves could be responsible for

0:03:17.240 --> 0:03:22.840
<v Speaker 1>transporting energy to the corona and heating that layer. Richard Morton,

0:03:23.000 --> 0:03:27.400
<v Speaker 1>a scientist for the UK's Northumbria University, explained when announcing

0:03:27.400 --> 0:03:31.600
<v Speaker 1>the discovery quote, our observations have permitted us to estimate

0:03:31.639 --> 0:03:35.160
<v Speaker 1>the amount of energy transported by the magnetic waves, and

0:03:35.400 --> 0:03:39.000
<v Speaker 1>these estimates reveal that the waves energy meets the energy

0:03:39.040 --> 0:03:49.720
<v Speaker 1>requirement for the unexplained temperature increase in the corona. Today's

0:03:49.720 --> 0:03:52.680
<v Speaker 1>episode is based on the article weird physics. The closer

0:03:52.720 --> 0:03:54.760
<v Speaker 1>you get to the Sun, the cooler it gets on

0:03:54.800 --> 0:03:57.240
<v Speaker 1>how stuff works dot Com, written by Patrick J. Tiger.

0:03:58.000 --> 0:04:00.400
<v Speaker 1>Brain Stuff is production of I heart Radio impart partnership

0:04:00.440 --> 0:04:02.080
<v Speaker 1>with how stuff Works dot Com, and it is produced

0:04:02.080 --> 0:04:05.120
<v Speaker 1>by Tyler Playing and Ramsay Young. Four more podcasts my

0:04:05.200 --> 0:04:08.080
<v Speaker 1>heart Radio, visit the i heart Radio app, Apple Podcasts,

0:04:08.160 --> 0:04:09.960
<v Speaker 1>or wherever you listen to your favorite shows.