In my previous blog post I posed a number of questions about the “oldest” software programs. There’s still time to enter the contest and offer your nominations in the comments. However, I’d like to offer my answer — answers, actually — to contest question #1: what’s the “oldest program of any kind in any medium that’s still running today?”

Biology offers some possible answers. There are thousands of individual organisms that are still living more than 2,000 years after they were born — still running the same DNA-coded programs. Rachel Sussman documents many in The Oldest Living Things in the World. The oldest by this standard is probably one of the few endangered ancient eucalyptus trees in Australia at about 13,000 years old.

However, that’s not a truly satisfactory answer. That’s actually the answer to a different question: what is the oldest software still executing its first run? A program running for 13,000 years without interruption is certainly a long-running program! If we consider DNA-coded programs that are still running today (in new invocations) that were first written long ago, we would turn to the so-called living fossils. Stromatolites, for example, are sedimentary structures composed of blue-green bacteria that have been operating on Planet Earth pretty much the same way for about 3.5 billion years.

Even that’s not quite the right answer, though. Our bodies probably contain fragments of genetic code first written at least 3.5 billion years ago, and some of that code is still invoked to fashion proteins and otherwise support our bodies’ fundamental biological processes. It’s hard to say which such program in which organism is the very oldest, but it’d be one of them (or a small group of them). Thank goodness: you simply wouldn’t exist without those ancient genetic programs supporting your development, birth, and biological operations.

Then there’s a more radical hypothesis, that our entire universe is nothing more or less than a spectacularly grand — to us, anyway — simulation. If that’s true, within the simulation the age of this gigantic program appears to be about 13.8 billion years old, the time since the Big Bang, with the big assumption that the simulation began with the Big Bang. (Maybe not.) However, the “true age” of the simulation is hard to define because time itself is a construction within the simulation.

To net it out, the “oldest” software in any medium is as old as life itself and maybe, just maybe, older than the universe. Either way this old software is really, really valuable, and thank goodness we can enjoy it.