Chemistry of Northern Lights

Hopewell Valley Student Podcasting Network

Chemistry Connections

Chemistry of the Northern Lights

Episode #11

Welcome to Chemistry Connections, my name is Ben Pollara and my name is Megan Meng and we are your host for episode #11 called The Chemistry of the Northern Lights. Today we will be discussing why the Northern Lights occur and the chemistry behind it.

Segment 1: Introduction to Northern Lights

For our segment we will be discussing the Northern lights. Scientifically referred to as Aurora Borealis, the Northern Lights are a natural light phenomenon that appear across Earth's great sky. Auroras display dynamic patterns of brilliant lights that appear as curtains, rays, spirals, or dynamic flickers covering the entire sky.

There are many myths behind the aurora borealis. The Eksimo tribes believed that they could summon the aurora to speak with their dead relatives. Inuit tribes feared the lights and carried knives to protect themselves against the aurora. But one thing is for sure now, all the myths behind the lights are FALSE. The science behind the Aurora Borealis is the TRUTH.

We will cover the origins of solar wind which send charged particles towards the earth. Then we will explain how those charged particles create collisions in our atmosphere that lead to the Northern Lights phenomenon.

Segment 2: The Chemistry Behind Northern Lights

Although the Northern Lights seem too gigantic to comprehend, breaking each process down makes the Northern Lights seem more simple. There are charged particles, collisions, electron excitations, and light waves that all go into the creation of the beautiful Northern Lights.

What is going on on the Sun?
The Sun is made up of helium and hydrogen.
The origin of solar reactions:

-Inside the sun, reactions are always happening. These reactions are called proton-proton fusion!!

Originating in the core of the sun, a lone hydrogen atom fuses with another hydrogen atom. These two protons usually break apart, but sometimes the hydrogen atoms stay fused. Once fused, a single proton transforms into a neutron because of its weaker nuclear force. A third proton then fuses with the proton-neutron pair, creating a helium atom and releasing gamma rays, or sunlight. Finally, two helium atoms collide, which causes two protons to be released and a heavier isotope of Helium.

The two protons then travel towards Earth’s atmosphere, colliding with atoms such as Oxygen and Nitrogen that make up Earth’s upper atmosphere.

. What are solar winds?
Storms on the sun cause solar winds
The solar wind is a continuous stream of charged particles that flows out of the Sun in all directions. The strength of the solar wind varies depending on the activity on the surface of the Sun. The Earth is mostly protected from the solar wind by its strong magnetic field.
So is that why Northern Lights only happen in the north and south pole?
Yes, actually Earth's magnetic field steers the charged particles towards the poles. The shape of Earth's magnetic field creates two auroral ovals above the North and South Magnetic Poles. This is where the charged particles from solar winds tend to be attracted to.
Solar charged molecules strike oxygen atoms and nitrogen atoms in the atmosphere. When the molecules collide, the atoms light up because of the excitation of their electrons!!
Electron excitation: What is it?
When an atom’s electrons are in the lowest energy level, then that atom is in its ground state.
If the electrons absorb energy, they excite and move to a higher energy level.

In the example of the Northern Lights, a charged particle collides with Nitrogen and Oxygen atoms in the atmosphere, exciting their electrons. Once the electron reaches a higher energy level, it loses energy and then falls back to its original energy level. When an electron moves back to its ground state, a photon is emitted with the amount of energy that is the difference between the two energy levels.

If a photon with more energy is released (like if an electron moves from energy level 6 to energy level 1), a light color on the latter half of the spectrum will be shown, like purple or blue. But, if a photon with little energy is released (like if an electron moves from energy level 2 to energy level 1), a light color of red or orange will be shown.

COLORS! !!!!

Since the different atoms in the atmosphere have different electron configurations, they will release different amounts of energy when excited.

Different colors:

1. Oxygen: Green and brownish-red colored lights.

2. Nitrogen: Blue and red colored lights.

3. Other Gasses: Helium and hydrogen emit purple and blue colored lights. There are also other gasses that get excited and emit light in the atmosphere. However, their wavelengths may not fall in the visible electromagnetic spectrum.

Other planets have different auroras This is because they have different atmospheres.
Jupiter’s aurora is blue, and Saturn’s is purple and red.
Auroras are possible on any planet or moon where energetic particles are present in the atmosphere.

Segment 3: Personal Connections

Crazily enough the northern lights are almost always present, day and night. 24 hours a day, seven days a week, 365 days a year. These lights are beautiful natural phenomena and give us a sense for how vast and interconnected our galaxy is. The interaction between the atmosphere and the small particles that make it create something so huge that we as puny humans can see it from Earth’s surface with the naked eye.

I would love to see the Northern Lights in my lifetime. They seem so peaceful, yet energetic. Do I believe in any of the old myths about the aurora? No. Do I still think the aurora has an interesting connection to the world we live in? Yes, completely. Although for the past 5 or so minutes we’ve broken down the Northern Lights to only a couple, microscopic reactions, the combination of those reactions give us an amazing sight to be seen. Who wouldn’t want to see the Northern Lights?

Thank you for listening to this episode of Chemistry Connections. For more student-ran podcasts and digital content, make sure that you visit www.hvspn.com.