I have long known that to look up into the night sky is to look far into the past. Looking up at the star Sirius, I am seeing 9 years into the past. Looking over at the star Antares, I am seeing 250 years into the past. And when I look the star Rigel, I am seeing 600 years into the past. Looking further still at the Andromeda galaxy, I am seeing one million years into the past. That is how long it takes the light of these stars and galaxies to reach us! We are not seeing them as they are now, but as they were then. The past, even the distant past, is very present to us.
The light of the sun takes 8.25 minutes to reach us. Thus we see the surface of the sun not as it is now, but as it was more than 8 minutes ago.
But I learned yesterday that the light of the sun is even older than I had thought. A little research on my part revealed this astonishing fact: the photons of light that reach the surface of the sun (and then reach us 8+ minutes later) were actually generated 100,000 years ago in the sun’s core.
Emerging from the sun’s core as the result of nuclear fusion, a photon of light enters the radiative zone (see diagram above). The plasma in that radiative zone is quite a maze for the photon to get through, such a maze that it takes the better part of 100,000 years to make the journey to the convective zone and the photosphere where it finally begins a rapid journey out into the vacuum of space.
Why does it take this long? Imagine being in a large room filled with people, trying to get to the door on the other side the room. But as you try to make your way across the room, person after person strikes up a conversation with you, delaying your progress. It won’t take you 100,000 years to get to the door, but you get the idea.
The diagram above shows the meandering, zigzag motion of a photon as it makes it way through a maze of plasma that detains the photon for up to 100,000 years!
Thus, the sunlight we currently bask in is much more than 8 minutes old; it’s 100,000 years old! The light we see today was made in the sun’s core back during the beginning of the last ice age.
The great mystery of time is on display for us at every moment. The past is present in many ways. And our past is on display and still present as well. If anyone on a planet near Rigel were looking back through a telescope at the earth right now, he would not see us as we are today, he might see Joan of Arc and her contemporaries of the 15th century. The light of our “today” will not reach Rigel for 600 years.
What is the present? That is mysterious as the sum total space of the universe and it depends on where you are. God, who is just as present at Rigel as He is here, has the same access to the images of 1415, as he does to those of 2015. Indeed, He is present at Andromeda just as much as here on earth; and a million years ago is just as accessible to Him as is now.
The future is even more mysterious, but that is just as available to God as is the past.
Do not miss the irony of the fact that the light of the sun (and the reflected light of the moon), by which we set our clocks and calendars to measure time and tell what time it is now, is 100,000 years old.
Does anybody really know what time it is? Only God, only God. Time is very mysterious and the more we think we know, it seems the less we really do.
All the days ordained for me were written in your book before one of them came to be. How precious to me are your thoughts, God How vast is the sum of them! Were I to count them, they would outnumber the grains of sand—when I awake, I am still with you (Psalm 139:16-18).