As I was walking the streets of New York this morning, I had a flash-back into my earlier career, into my particle-physics / cosmology years. There was a new stack of issues of the New York Times lying, nicely tied and fresh from the press, on the pavement. I glanced at the front page and immediately recognized the picture from my “good old days” in academia.

The funny thing is, the picture itself may be news, in that it has been taken recently, but it is a picture of the very oldest thing you will ever (!) see in the Universe. Dig that!

Because of the minor “miracle” that the speed of light is actually finite, what happens is that when you look at a star, you don’t see how it is today, you see how it was when the light that’s hitting your eye now was sent by that star. And that may be years ago (for the very, very, closest stars), thousands of years ago (for most of the stars you see with the naked eye), millions of years ago (for most visible galaxies), or billions of years ago (for quasars, which you still see although they all died over 10 billion years ago, when the Universe was less than 3 billion years old). So yes, you can see the universe how it once was, rather than how it is today. In fact, you can only see how it once was, never how it is today. And the further you look away, the further you look “back in time”. You have no choice in the matter. That’s the only way it works out when light needs time to get to you.

But there is a limit how far you can see what happened in the past. Not because you can’t look further, but because there is nothing to see. The NY Times picture shows you how the Universe was 370,000 years after the Big Bang (if you believe in that sort of thing, which I do). Before that time, light in the sense that we know it didn’t really exist. Electromagnetic waves and photons were around for sure, but they were constantly being messed with by all the free electrons and protons fluffing about, and it was all a big mess with nothing to see, and light not really travelling on a straight line. This killed (at least) two essential features photons and waves need to be understood as “light”: The weren’t really travelling on straight lines, and their “color” (frequency or energy) kept changing all the time too. Even if there had been “things” to look at, and if there had been an observer to look at them, that observer would have seen nothing but random noise. At 370,000 years, the Universe became cool enough for electrons and protons to find each other, form atoms, and actually stay together. That means the other particles stopped messing with the light, and light, rather suddenly, started to travel along straight lines and keeping it’s color, which — thankfully — it’s pretty much done ever since. What we see in this picture is actually the moment when, if anyone has/had said “let there be light”, the Universe obliged. That is why you will never get a clear picture of what was going on before then. Never ever. Because even if you had been around at the time before then, you wouldn’t have see a thing even then. Looking at things would have been pointless. Light was just a mess at best, and for all I know we would have called it something completely different, maybe “snowstorm”, who knows?

So what you see on that NY Times image is the oldest news you will see photographic evidence of, ever. And “we”, the humans, just managed to make a very good picture of it (there were plenty of good ones before, but not quite so good. In fact the first one was so confusing to the discoverers, they thought that bird droppings must have messed with their apparatus. They eventually worked it out and got a Nobel Prize for their discovery). Old news it may be, but it’s pretty cool news too!

An important aside, if you are a creationist and don’t believe in the Big Bang, you would still agree that these photons come from the moment the Universe “let light be”. Because if you can agree that these lightrays don’t come from any particular concrete object, it follows they must have been travelling towards your eyes (or towards the camera or radio-telescope) ever since day there was light. These light-rays are then the oldest things you will ever see in this Universe.

What does it have to do with sustainability? Not a lot perhaps, except that what you see here actually happened 9 billion years before the Earth even existed, which is most probably longer than the Earth will continue to exist from now. Think about that, and perhaps there is a small reminder in there that whatever we manage here on Spaceship Earth, even including time, is a finite resource.