Matter is converted to light in stars like the Sun. Four hydrogen atoms fuse to make one helium atom. The mass of the four hydrogen atoms is greater than the mass of the helium atom and the lost mass turns into energy according to Einstein’s equation, E = mc2. E is the energy released, m is the mass lost, and c is the speed of light. This is an excellent example of the far-reaching influence of the speed of light.

Every second, stars convert millions of tonnes of hydrogen into helium and energy. How does this energy escape from stars? Only as light. Countless photons stream out from every star into space at 300 000km/sec until they strike something or they go on forever. If a photon is not absorbed, it is immortal. Almost all life on Earth is fuelled by starlight. Light is the elixir of life that plants need for photosynthesis.

Even at 300 000km/sec, Sunlight takes eight minutes to reach the Earth. Light from the nearest star, Proxima Centauri, takes four years to reach us. There is an amazing range of stars: white and brown dwarfs, yellow stars like our Sun, red and blue giants. Our Sun is just right for us, shining down nearly 1400 watts per square metre of energy onto Earth’s surface. This lights, warms and feeds every living thing. Imagine how hot it would be if we revolved around Rigel (the bright star at the foot of Orion); it’s 50 000 times brighter than our Sun and another star, e-Carinae, is over a million times our Sun’s power.

Most astronomers insist that stars and starlight come from the “big bang”. A recent comment concluded that the Hubble telescope’s deep space images show an “early universe that defies our current understanding of cosmic evolution”. It doesn’t make sense – to them. The obvious but unacceptable answer is that their current theories are wrong! God is light and we stand in awe of His greatest creation – LIGHT.

Consider some more things light can do – and be amazed.

Mixing coloured light

Every colour can be created by mixing various amounts of red, green and blue light. See Figure 3.

red + green – yellow

red + blue – magenta

green + blue – cyan

red + blue + green – white

Rainbows

When you see a rainbow in a sun-shower, you only see the bow if you look the same way that the sunlight is shining. We must follow the light and see where it leads us. When white sunlight strikes a raindrop, some light is reflected but most is refracted (bent) as it enters the drop. Different colours are bent different amounts (red least, violet most, see Figure 4).

The light is internally reflected at the back of the raindrop and bent further as it exits the raindrop. If you measure the total deviation of the light, the angle between the entering ray and the exit ray is greatest for red and least for violet. Thus, as you look at the falling raindrops, you see the red rays from high raindrops and violet light from lower raindrops. The rainbow is a complete spectrum, from top to bottom, red–orange–yellow–green– blue–indigo–violet. Sometimes the rain cloud is high enough for a double rainbow to form. The colours are reversed in the top rainbow. Yahweh shows us that violet (the royal king-priest) encloses the red (in the middle) showing that Jesus Christ (purple) conquers sin (red).

Rene Descartes (the French philosopher scientist) traced the path of over 3000 rays in different positions in raindrops. His startling discovery was that raindrops concentrate the different colours so that the beams of red through to violet are brighter than you would expect (Figure 5).

Yahweh’s “everlasting covenant” (Gen 9:12– 16), which Paul applies to Christ’s victory over sin (Heb 13:20), was first seen in the rainbow that signalled the end of the Flood (Figure 6). The rainbow promises us Christ’s peace and is a feature of the mighty angel whose judgments lead us to the Kingdom (Rev 10:1).

How is light produced?

Atoms emit light when they are excited. This happens in a fluorescent tube, a neon light or the yellow sodium vapour lamps used as street lights. Here’s how it works. Atoms have a positively charged nucleus and negatively charged electrons orbiting the nucleus. The negative electrons are strongly attracted to the positive nucleus. So, when an atom absorbs energy – from electricity or intense heat such as a flame – an electron moves away from the atom’s nucleus (Figure 7). An excited electron can suddenly fall back to its normal state and emits the absorbed energy as a photon. Sodium vapour lamps emit yellow photons, neon tubes orange photons and fluorescent tubes UV light. In fluorescent tubes, the white powder inside the tube changes the UV light to visible white light. For those who want to know, this is called a line emission spectrum because the light is all one colour (monochromatic).

Every element absorbs and emits light in different amounts so that the colour of the photons they emit are unique to that element. This is how scientists identify tiny amounts of elements in mixtures – they all have different light signatures. Helium was discovered in the Sun by its light signature years before it was found on Earth. The light emitted from stars tells us their exact chemical composition.

Lasers

The most important discovery in the last 50 years is the laser. Laser light is special because it is made up of photons or waves that are perfectly in step with each other. The photons are exactly the same colour, they are in phase and they never interfere with other waves in the beam. Photons that are ‘in step’ are called coherent light. Listen to what one physicist says:

“Coherent light is produced by a laser (acronym for light amplification by stimulated emission of radiation). Within a laser, a light wave (photon) emitted from one excited atom stimulates the emission of light from a neighbouring atom so that the crests of each wave coincide. The waves stimulate the emission of others in a cascade fashion and a beam of coherent light is produced. This is very different from the random emission of light from atoms in common light sources.

“The laser … is a converter of energy that takes advantage of stimulated emission to concentrate … the input energy.” (Hewitt, p.494).

Figure 8 shows why laser light is so powerful. It is easy to rewrite this story with Scriptural characters:

The first wave (photon) emitted is Christ. The wave-photons that immediately followed him were the Apostles. The laser beam built its strength as “in-step” wave-photons were added – at Pentecost and afterwards in Acts.

Every photon is in phase, the same colour and they never deviate from their straight path. A laser beam fired at a reflector on the moon will be much the same width on its return. No other light beam can do this.

We are called to be ‘laser lights’ because “a city that is built on a hill cannot be hid” (Matt 5:14). We should be lighthouses on a stormy sea (Phil 2:15).

Light and darkness

As we have seen, science needs two incompatible models to explain light – waves or photons (bundles of energy). Light cannot be real waves because waves can only pass through material substances (air, water, earth, etc.) but light happily speeds through empty space. Particles like photons can pass through space and this is one reason for describing light as photons. But light fills every space in which it shines like waves spreading on a pond. How can particles of light fill a space? You’d expect there to be dark spaces between photons. But that doesn’t happen!

Yahweh created light; light that does things we cannot understand or describe. Light always conquers darkness because darkness is the absence of light. Once there is some light in a space, it fills the space, however dimly, and darkness disappears. Particles cannot do this, waves can but waves cannot pass through space. Only God knows what light really is. Let us heed Christ’s warning, “If therefore the light that is in thee be darkness, how great is that darkness” (Matt 6:23).

How can light be darkness? To us, this is impossible but Jesus is warning us that light belongs to God and unless we recognise His genius, we are in a darkness that can extinguish the gospel of Jesus Christ.