Are We the Ultraviolet Light of the World? Or the X-Rays?

An astronomer ponders one of Jesus' most memorable sayings.
Are We the Ultraviolet Light of the World? Or the X-Rays?
Image: NASA, ESA, CXC / Flickr

When Jesus defined himself as “the light of the world,” listeners probably associated those words with common objects well known to them: the hot sun of Judea, the stars twinkling in the sky, the moon shining during the night, torches they carried on the roads, small oil lamps used in their houses, or bonfires lit when camping on a long trip.

In our current age, we associate the light with many other things: the screen of a smartphone, a laptop we use for work, the traffic lights on the streets, fireworks on New Year’s Eve, a television, a laser pointer, car lights, or a child’s toy.

As an astronomer, the majority of my work is based on light. I study astronomical observations of celestial bodies, obtained through telescopes, in order to understand the physical processes behind them. From astronomy, I know there are many kinds of light, so I wondered how that can teach me more about the expression “the light of the world.”

To start with, what is light? Light is electromagnetic radiation that can manifest itself in different ways depending on the range of energy in which we observe it. For example, we have visible light, x-rays, radio waves, ultraviolet light, or microwaves, to name a few. The interesting thing is that, although they manifest themselves in different ways, all these types of light are part of the same physical phenomena. Another fascinating property of the light is that, although they have different energies, all electromagnetic radiation travels at the same speed: 300,000 km/s, a universal constant called the speed of light.

The fact that light manifests itself in different ways is very useful in astronomical research because by observing a celestial object through different energy ranges, we can obtain much more information about its properties and characteristics than using one “type of light” alone. Let’s take, for example, a single galaxy.

By observing the galaxy with an optical telescope (that is, in the range of visible light), we can see the stars within it. However, if we observe the same galaxy with an infrared telescope, we will not observe the stars but the cold gas and dust between the stars, a matter known as the interstellar medium. Ultraviolet observations, on the other hand, will show the very hot stars. Finally, if we observe the same galaxy with an x-ray observatory, we will see the hot gas and other high-energy objects. In this way, and thanks to our access to the entire energy spectrum of the light, we can obtain information that would otherwise be inaccessible to us.

In no case can we say that one way of observing such galaxy is more important than another. On the contrary, they are all complementary ways that allow us to have a more complete and detailed picture. In fact, the arrival of new observatories that allow access to other energy ranges has always meant a considerable step forward in the astronomical research.

Jesus defined himself as the “light of the world. Whoever follows me will never walk in darkness, but will have the light of life” (John 8:12). If we do the analogy with the light as described above, we can think that in the same way that light manifests itself through different energies, Jesus has revealed himself to this world in many ways, showing, in Peter’s words, “God’s grace in its various forms” (1 Pet. 4:10).

Each one of us has had a unique experience with Jesus, but it is through the sum of these multiple personal experiences that we see a bigger picture of who he is. As light, Jesus is one, even when he reveals himself in different ways. For this reason, we must share our testimony, telling others in what way we have known Jesus and what kind of his “light” illuminated our life. But at the same time, we must learn to value the testimony of others. We must ask ourselves: How has Jesus revealed himself to the people around me? What kind of “light” have they seen? We should not think that the way Jesus has manifested himself to one person is more important or better than another. Nor should we think that what we have known about him is all there is to know, limiting the revelation of Jesus to what only I can see. The knowledge of God is much deeper.

Jesus not only described himself as the light of the world, but he also said about us, his disciples, that “You are the light of the world. A town built on a hill cannot be hidden. Neither do people light a lamp and put it under a bowl. Instead they put it on its stand, and it gives light to everyone in the house” (Matt. 5:14–15).

The disciples of Jesus are very different from each other. We have different physical appearances. We have different cultures. We have different talents, gifts, and abilities given by God. We have different personalities. We have different areas of influence. However, just as light has multiple energies but all travel together at the same speed, each one of us shines in different ways and places but we are united through Christ. Although the light of God manifests itself in different ways through his disciples, we are one.

That is why we must value the “light” that is in others recognizing that each one fulfills its own function, complementary to ours. Although this light shines in different ways, we all have the same goal: to glorify God. Only when we recognize how much we need each other can we put aside all those things, such as envy and jealousy, that take us away from the fulfillment of the Great Commission.

How many times have I believed that one type of light is more important than another? How many times have I believed that my light is insignificant compared to another? How many times have I wanted to shine differently than the way God has called me?

We are the light of the world and, as such, we shine and the darkness flees away.

Efrain Gatuzz is an astronomer from Venezuela currently working in Munich, Germany.

April
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