Weather forecasters this week have put their listeners on notice there is a possibility for residents in the northern tier of states to be able to view the phenomenon known as the Aurora Borealis. This sight is more common to people living in places like Iceland, Siberia and Alaska, but it can occasionally be seen from lower latitudes as well. The National Oceanic and Atmospheric Administration (NOAA) in the United States provides a forecasting tool which predicts where the Aurora Borealis is most likely to be seen.
This light effect cannot be seen year-round, and is only visible under ideal conditions. Numbers of tourists venture to the north just for a chance to see this display. The lights produced vary in shades of green, red, yellow and purple. What is even more fascinating is the lights are not stationary in the sky but appear to shimmer and dance across the horizon. In some instances, observers are even able to hear the Aurora. What few observers realize is how this phenomenon tells us something about the fine-tuning of the universe.
To the best of our understanding, the light is produced by the interaction between the earth’s atmosphere and the solar wind from the sun. The interior of the sun, at temperatures in the millions of degrees, contains fast moving atomic particles which are colliding with one another. Some of the electrically charged particles (protons and electrons) end up being ejected from the sun in all different directions at high rates of speed. This is solar wind.
Solar wind has severe consequences for biological entities. These high velocity particles would shred your DNA, and also strip away a planet’s atmosphere. We are protected from this devastation, however, by the presence of earth’s magnetic field. Not every planet is fortunate enough to be equipped with such a protective mechanism – the future residents of Mars, for instance, will need to take special precautions.
The earth’s magnetic field envelopes the planet like a donut-shaped bubble with the donut’s holes positioned at the poles. The magnetic field deflects the solar wind away from most of the planet, but these “donut holes” permit solar wind to interact with the upper layers of our atmosphere at both poles.
The high velocity (high energy) electrons and protons from the solar wind follow the edges of the magnetic field down into the holes at the poles. They strike oxygen and nitrogen atoms in the upper atmosphere and transfer some of their energy to these atoms. The excited oxygen and nitrogen atoms will eventually calm back down again, and release their excess energy in the form of photons – the wave-particles of light.
Having a magnetic field around our planet is central in making the Auroras possible. So, what makes the magnetic field possible? As we understand it, the magnetic field is generated by activity at the core of our planet. The solid inner core is composed largely of iron, and the movement of material around the core is what we think is generating the magnetic field. To move material around in the center of the earth, though, requires a heat source. This heat is generated by the decay of radioactive elements.
It must be recognized that having the conditions mentioned above is more easily said than done:
- It cannot be taken for granted that our planet in fact has an iron core which is substantive enough for this effect – all planets don’t have iron cores.
- The materials moving around the core have to be of the right composition and the right consistency owing to ideal pressure and temperature.
- The pressures at the core are related to the gravitational effects due to the overall size of the planet.
- The temperatures at the core are influenced by the decay of radioactive material which must be of a certain proportion in the core in order to produce the precise amount of heat.
- If the magnetic field were too strong, the dynamics of our atmosphere would suffer (e.g. no cloud formation).
- If the magnetic field was not strong enough, we would suffer the effects of solar wind.
When we realize that our solar system likely resulted from the coalescing of atoms ejected from a super nova – an exploding star – the probability that all the right amounts and proportions of elements coming together in a way which would generate a magnetic field – and the Aurora borealis – is astronomically small. By and large, our universe is a very hostile environment when it comes to the existence of life. Unless conditions are just right, no life can exist.
So, if you ever have the chance to witness the Aurora Borealis in person, remember that what underlies this phenomenon is what appears to be a purposeful arrangement of matter essential for the existence of life. I would suggest such a purposeful arrangement is so unlikely to result from the random collision of atoms in space that these conditions can best be explained by intelligent agency.
There are many more finely-tuned conditions which must be met to make life possible on this planet than the several mentioned here. Suggestions for further reading:
The Privileged Planet by Guillermo Gonzalez and Jay W. Richards (Regnery, 2004)
Improbable Planet: How Earth Became Humanity’s Home by Hugh Ross (Baker, 2016)