Faith & Science
Intelligent Design
In Aurora Borealis, Scientific and Aesthetic Design Arguments Meet
This weekend the strongest geomagnetic storm in 20 years brought the aurora borealis to Seattle and elsewhere. My PhD is in geology, but both my PhD and master’s thesis projects were in paleomagnetism — the study of Earth’s ancient magnetic field. For years I’ve hoped to glimpse the northern lights (or southern lights — I lived in Johannesburg for four years!), but to no avail. However, on Friday night around 11 pm my wife and I decided to have a little nightcap on our back deck and she spotted it in the sky. We called our friend and colleague Dr. Brian Miller and he came over. Although all three of us were sick (you may have heard me coming down with a cold during my junk DNA debate with Dr. Dan last week), for about an hour we sat outside and enjoyed a brilliant light show. Just above and below are two photos, with more to follow:
Before the rest of the photos, let’s talk some science.
What Causes the Aurora?
Our sun emits not just electromagnetic radiation (e.g., light) but also “radiation” in the form of electrically charged particles ejected from the sun’s mass. These charged particles of the “solar wind” are composed primarily of hydrogen ions and electrons, but you also get some alpha particles (helium atoms), as well as trace amounts of heavier elements like carbon, nitrogen, oxygen, neon, and even some heavier elements like magnesium and iron. Here’s what Stanford’s Solar Center website says:
The composition of the solar wind is a mixture of materials found in the solar plasma, composed of ionized hydrogen (electrons and protons) with an 8% component of helium (alpha particles) and trace amounts of heavy ions and atomic nuclei: C, N, O, Ne, Mg, Si, S, and Fe ripped apart by heating of the Sun’s outer atmosphere, that is, the corona. SOHO also identified traces of some elements for the first time such as P, Ti, Cr and Ni and an assortment of solar wind isotopes identified for the first time: Fe 54 and 56; Ni 58,60,62. [Internal citations omitted.]
When these charged particles hit our atmosphere, they excite electrons in oxygen or nitrogen molecules of our atmosphere causing them to emit light. From what I’ve been reading, green and blue emissions dominate because oxygen tends to emit green color and nitrogen blue at lower altitudes of the atmosphere, whereas red colors tend to be emitted by oxygen or nitrogen at higher altitudes. Wikipedia says there’s still a lot we don’t understand:
A full understanding of the physical processes which lead to different types of auroras is still incomplete, but the basic cause involves the interaction of the solar wind with Earth’s magnetosphere. … auroral arcs and other bright forms are due to electrons that have been accelerated during the final few 10,000 km or so of their plunge into the atmosphere.
Now because these particles are electrically charged, they follow along magnetic field lines. Earth has a strong magnetic field which under normal solar wind conditions, serves as a deflector shield, preventing these charged particles from stripping off our atmosphere or reaching most of Earth’s atmosphere or surface where they might cause harmful mutations in living organisms. This deflector shield protection against the solar wind is visualized in the image below:
The image above gives a rough idea of the shape of Earth’s magnetosphere. Under normal conditions, when charged particles from the solar wind hit the Earth’s magnetic field, they are either completely deflected around the planet, or channeled along magnetic field lines to hit the Earth at its poles. Because the polar areas are extremely cold or lacking in land mass, very little life is there, so the radiation that is channeled to those areas does very little damage to life.
So why are these particles normally channeled to the poles? As you can see in the schematic image below, the magnetic field of the Earth roughly approximates a dipolar bar magnet aligned with Earth’s spin axis. Under such a magnetic field, “field lines” of Earth’s magnetic field intersect with the surface of the Earth at a far greater density at higher latitudes (further from the equator) than lower latitudes (like the equatorial region, where field lines are generally parallel to Earth’s surface):
This just has to do with the shape of dipolar magnetic fields — something you can easily visualize yourself by putting iron filings on a sheet of white paper while holding a magnet beneath.
Because the charged particles of the solar wind follow magnetic field lines, they generally will not reach the atmosphere (or surface) of our planet at lower latitudes because there are so few field lines that intersect with the planet in those regions. Thus, normally they get channeled only to higher latitudes near the poles and so you usually only see the aurora effect at very high latitudes. Damage is averted.
Nonetheless, there are geomagnetic field lines that intersect with the surface virtually everywhere on Earth, just at varying densities. So when you get LARGE ejections of solar material during a major geomagnetic storm, you will get more charged particles interacting with Earth’s magnetosphere, and enough charged particles will find their way to field lines at the lower latitudes to cause the aurora effect far from the poles.
Because we were in the middle of a geomagnetic storm caused by a major solar eruption which spewed solar mass out towards Earth, we enjoyed a beautiful aurora borealis here in Seattle at about 47.6° N latitude. I’m even getting photos from friends in South Africa who saw the southern lights (aurora australis) in Cape Town at about 33.9° S latitude!
A Privileged Planet
Earth’s strong magnetic field is actually a necessary habitability parameter of the Earth. And Earth is unique in our solar system in that it is the only rocky planet that has a strong magnetic field. Earth’s unique properties are seen in the plot below which I made years ago:
What you can see in the diagram above is that Earth is the only planet with a small diameter (i.e., a rocky planet) that also has a strong magnetic field. True, there are other planets in the solar system with strong magnetic fields — but they are all gas giants that lack stable surfaces where life could find nice habitable platforms on which to live. So Earth is unique in that it’s the only rocky planet with a magnetic field capable of providing strong protection against the solar wind and other radiation coming from space. Earth is the only planet in our solar system that fulfills these habitability requirements — scientific evidence of our planet’s design!
Aesthetic Arguments for Design
But not all design arguments need to be scientific — as Ann Gauger has explained, design arguments can also be aesthetic.
Discovery Institute is not a religious organization, but as a Christian I’d like to give my personal take on these aesthetic arguments:
I believe that the beauty of the aurora borealis (or more generally, the “aurora”) is another way of appreciating that our planet was designed by a Mind who not only is brilliant but also loves us. I can hardly take credit for the beauty of the shots below — 99.99 percent of the credit goes to the God who made the sun, the Earth, and the laws of electromagnetism (and perhaps 0.01 percent goes to Apple which made my iPhone that made taking a bad photo virtually impossible).
Here are a shot looking out towards the horizon, followed by one from my colleague Dr. Emily Sandico:
Here are some shots looking straight up where I could see streaks coming down from what looked like a vortex of magnetic particles streaming down from space. These red, green, and purple streams of particles would then turn into the green sheets you saw in the photos above:
Final Reflections
Again, these are not scientific arguments for design — but they flow naturally from the deeply moving experience of what we saw Friday night. No matter who you are or what you believe, you appreciate the beauty of this natural display. Why is that?
The Judeo-Christian worldview teaches that God made the universe and that every human being is made in the image of God. Whether or not you believe in God and worship Him, you were made in that image. It’s an intrinsic property of who you are, regardless of whether or not you believe it or acknowledge it.
Being made in the image of God means, in part, that you were made to appreciate some of the kinds of things that God appreciates — things like beauty, elegance, sophistication, and complexity. And beauty, elegance, sophistication, and complexity were all on stunning display in the aurora witnessed by much of the world on Friday night.
Indeed, I’m not sure how a materialist would explain the profound response people feel upon seeing the aurora. An evolutionary psychologist might say it results from some ancient vestigial neural module which made your ancestors seek colored fruit on trees or deep blue/green water for hunting fish. I’m sorry but an explanation like that falls very short of explaining the moving emotional experience you have upon seeing the aurora.
Indeed, according to evolutionary biology, your presumed evolutionary ancestors lived in Africa — a continent at low latitudes where they probably rarely if ever saw phenomena like the aurora. If your evolutionary ancestors did ever see the aurora, it was far too rare to have any selective effect upon your behavior. Yet you can’t help but be in deep and profound awe of it.
You appreciate the aurora borealis or aurora australis because you were not created by strictly material evolutionary processes. If you think evolutionary psychology or some other just-so story explains your profound reaction to such natural beauty, I can only respond with the words of President Joe Biden: “C’mon man.”