1 00:00:15,730 --> 00:00:23,570 Every second, one million tons of matter is blasted from the sun at a velocity of one million miles per hour. 2 00:00:23,809 --> 00:00:27,050 And it's on a collision course with Earth. 3 00:00:28,030 --> 00:00:32,369 But don't worry, this isn't the opening of a new Michael Bay movie. 4 00:00:32,990 --> 00:00:35,770 This is the journey of the polar lights. 5 00:00:36,950 --> 00:00:42,109 The northern and southern lights, also known as the aurora borealis and aurora australis respectively, 6 00:00:42,109 --> 00:00:46,310 occur when high-energy particles from the sun collide with neutral atoms in our atmosphere. 7 00:00:46,869 --> 00:00:52,270 The energy emitted from this crash produces a spectacle of light that mankind has marveled at for centuries. 8 00:00:53,030 --> 00:00:56,509 But the particle's journey isn't just as simple as leaving the sun and arriving at Earth. 9 00:00:56,990 --> 00:01:01,409 Like any cross-country road trip, there's a big detour, and nobody asks for directions. 10 00:01:02,170 --> 00:01:05,750 Let's track this intergalactic voyage by focusing on three main points of their journey. 11 00:01:06,109 --> 00:01:11,430 Leaving the sun, making a pit stop in the Earth's magnetic fields, and arriving at the atmosphere above our heads. 12 00:01:13,549 --> 00:01:17,010 The protons and electrons creating the northern lights depart from the sun's corona. 13 00:01:17,650 --> 00:01:21,310 The corona is the outermost layer of the sun's atmosphere and is one of the hottest regions. 14 00:01:22,030 --> 00:01:27,549 Its intense heat causes the sun's hydrogen and helium atoms to vibrate and shake off protons and electrons, 15 00:01:28,069 --> 00:01:30,409 as if they were stripping off layers on a hot, sunny day. 16 00:01:31,329 --> 00:01:33,250 Impatient and finally behind the wheel, 17 00:01:33,349 --> 00:01:38,030 these freak protons and electrons move too fast to be contained by the sun's gravity 18 00:01:38,030 --> 00:01:41,609 and group together as plasma, an electrically charged gas. 19 00:01:41,609 --> 00:01:46,609 They travel away from the Sun as a constant gale of plasma, known as the solar wind. 20 00:01:46,609 --> 00:02:01,340 However, the Earth prevents the solar wind from traveling straight into the planet by setting up a detour, the magnetosphere. 21 00:02:01,340 --> 00:02:08,340 The magnetosphere is formed by the Earth's magnetic currents and shields our planet from the solar winds by sending out the particles around the Earth. 22 00:02:08,340 --> 00:02:14,340 Their opportunity to continue the journey down to the atmosphere comes when the magnetosphere is overwhelmed by a new wave of travelers. 23 00:02:14,340 --> 00:02:21,340 This event is coronal mass ejection, and it occurs when the Sun shoots out a massive ball of plasma into the solar wind. 24 00:02:21,340 --> 00:02:28,340 When one of these coronal mass ejections collides with Earth, it overpowers the magnetosphere and creates a magnetic storm. 25 00:02:28,340 --> 00:02:37,340 The heavy storm stresses the magnetosphere until it suddenly snaps back, like an overstretched elastic band, flinging some of the detoured particles towards Earth. 26 00:02:37,340 --> 00:02:41,340 The retracting band of the magnetic field guides them down to the aurora ovals, 27 00:02:41,340 --> 00:02:45,340 which are the locations of the northern and southern lights. 28 00:02:45,340 --> 00:02:48,340 After traveling 93 million miles across the galaxy, 29 00:02:48,340 --> 00:02:52,340 the sun's particles finally produce their dazzling light show with the help of some friends. 30 00:02:52,340 --> 00:02:55,340 Twenty to two hundred miles above the surface, 31 00:02:55,340 --> 00:02:58,340 the electrons and protons meet up with oxygen and nitrogen atoms, 32 00:02:58,340 --> 00:03:01,340 and they sure are happy to see each other. 33 00:03:01,340 --> 00:03:03,340 The sun's particles high-five the atoms, 34 00:03:03,340 --> 00:03:07,580 atoms, giving their energy to the Earth's neutral oxygen and nitrogen atoms. 35 00:03:07,580 --> 00:03:11,340 When the atoms in the atmosphere are contacted by the particles, they get excited and emit 36 00:03:11,340 --> 00:03:13,120 photons. 37 00:03:13,120 --> 00:03:16,020 Photons are small bursts of energy in the form of light. 38 00:03:16,020 --> 00:03:20,159 The colors that appear in the sky depend on the wavelength of the atom's photon. 39 00:03:20,159 --> 00:03:24,099 Excited oxygen atoms are responsible for the green and red colors, whereas excited nitrogen 40 00:03:24,099 --> 00:03:27,460 atoms produce blue and deep red hues. 41 00:03:27,460 --> 00:03:35,569 The collection of these interactions is what creates the northern and southern lights. 42 00:03:35,569 --> 00:03:39,270 Polar lights are best seen on clear nights in regions close to the magnetic north and 43 00:03:39,270 --> 00:03:40,650 south poles. 44 00:03:40,650 --> 00:03:44,810 Nighttime is ideal because the aurora is much dimmer than sunlight and cannot be seen in 45 00:03:44,810 --> 00:03:45,810 daytime. 46 00:03:45,810 --> 00:03:50,629 Remember to look up at the sky and read up on the sun's energy patterns, specifically 47 00:03:50,629 --> 00:03:56,889 sunspots and solar flares, as these will be good guides for predicting the auroras.