The Speed of Light

Light travels at 186 thousand miles per second. That means it travels about six trillion miles in a year, so that’s the distance in a light year.

The sun is “only” about 0.000016 of a light year (93 million miles) from Earth; its light reaches us in about eight minutes twenty seconds. After the sun, the next nearest star to Earth is Proxima Centauri, which is about four light years away, so its light takes about four years to reach us.

Light from Polaris (the North Star) travels 680 years before reaching Earth.

That’s about how many years passed between the times in which Isaiah and Jesus preached. Isaiah lived in a time when the darkness of empire—the Assyrian empire, in the case of eighth-century Judah—was creeping into the land. He looked forward to a time when the Lord’s light would drive the darkness away.

Isaiah said,

In the former time he brought into contempt the land of Zebulun and the land of Naphtali, but in the latter time he will make glorious the way of the sea, the land beyond the Jordan, Galilee of the nations. The people who walked in darkness have seen a great light; those who lived in a land of deep darkness on them light has shined (9:1b-2).

Matthew says about Jesus,

He left Nazareth and made his home in Capernaum by the sea, in the territory of Zebulun and Naphtali, so that what had been spoken through the prophet Isaiah might be fulfilled: "Land of Zebulun, land of Naphtali, on the road by the sea, across the Jordan, Galilee of the Gentiles the people who sat in darkness have seen a great light, and for those who sat in the region and shadow of death light has dawned." From that time Jesus began to proclaim, "Repent, for the kingdom of heaven has come near" (4:14-17).

Isaiah’s hopes for the coming light were fulfilled in other ways through the years—the people returning from Babylonian exile in the late sixth century no doubt saw that event as a fulfillment of Isaiah’s words, for example—but for Matthew and the early church, Jesus’ ministry was their most complete fulfillment. In Jesus, the light for which Isaiah looked had come.

Some stars that are visible to the naked eye are as far as two thousand light years away, so it’s taken two thousand years for their light to get to us. Here we are, living two thousand years after Jesus. Do you ever wonder how much of Jesus’ light has made it to us? How can we let our lives be more open to the light of Jesus’ love and grace so it will drive away the darkness of pride and power that sows dissension and disunity?

It didn’t take two thousand years for such issues to develop. Jesus’ original disciples dealt with the darkness that accompanies the quest for power with its accompanying pride and jealousy. And it was only about twenty years after Jesus lived that Paul was imploring the church at Corinth to overcome its divisions (1 Cor 1:10-18). So it’s not surprising that we still have trouble letting the light drive away our darkness.

But light is stubborn. It keeps going. It keeps coming.

Today’s powerful telescopes can detect the light from objects as far as 10-15 billion light years away. When scientists see the light from those objects, they see light that has been traveling for ten to fifteen billion years.

If humans still exist somewhere ten to fifteen billion years from now (it’ll have to be somewhere other than Earth, since our sun will die in around five billion years), God’s light of love and grace, which is most fully revealed in Jesus, will still be trying to reach us ...

This post first appeared in a slightly different form on Coracle, the blog of NextSunday Resources.