I was meditating on time today, perhaps because it is my 52nd birthday. But also on account of some new mysteries I have learned about the light of the Sun that reaches this earth.
I have long known that to look up in the night sky is to look far into the past. Looking up at the star Sirius I am looking nine years into the past. Looking over to the star Antares I am seeing 250 years into the past. Looking over at the star Rigel I am looking 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.
Even in the daylight, 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 8 minutes ago.
But I learned yesterday that the light of the sun is even older than I ever thought. A little research on my part revealed this astonishing fact. The photons of light that reach the surface of the sun and head out to us in eight minutes were actually generated 100,00 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? Consider an image of you, at one side of a large room filled with people, and you want to get to the door on the other side. But on the way many, many people want your attention and strike up conversations and thus delay your journey across the room.
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 light we currently bask is much more than 8.25 minutes old! It is 100,000 years old! The light we currently enjoy was made in the sun’s core back during the beginning of the last ice age.
There is a great mystery of time on display for us at every moment. The past is present in many ways. And our past is “out there” on display and still present as well. If there is any one on a planet near Rigel and they look back through a telescope to earth, say to France, they do not see us now, they see Joan of Arc and other events of the 14th Century taking place. The light of our “today” will not reach Rigel for 600 years.
What is the present? That is mysterious is the sum total space of the universe and it depends on where you are. God, who is just as present as Rigel as here, has the same access to the images of France in 1450, as he does to 2013. Indeed, being present at Andromeda just as much as here on earth, 1 million years ago is just as present to him as now.
The future is even more mysterious, but that is just as present to God as the past and distant past is.
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 the present, to tell time 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 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
Sites That Link to this Post
- Pastoral Sharings: "Love Your Neighbor" | St. John | July 13, 2013