Tuesday, 23 August 2011

Are we first?

Are we alone in the universe? It's a big question. Actually it's the biggest question. Far too for anyone to pretend they have the answer, however it is entirely possible to answer a slightly different but almost equally fascinating question. Are we first? By which I mean is it likely, given the incredibly young age of the universe, that we are the first intelligent species to arise? Again it's impossible to be definite but there is some interesting number crunching to be done on the subject.

I wish I had a blackboard.

The human body, and indeed the bodies of all complicated life on earth, are made up of a handful of basic elements. Oxygen is the most common representing a massive 65% of your mass, next is Carbon clocking in at 18%. Hydrogen, the most common element in the universe, makes up 10%, most of it combined with Oxygen in the form of water. Nitrogen then contributes 3%. Calcium a key component of your skeletal structure only adds up to 1.5% of who you are. Phosphorus, the key to the amino acids that make up your DNA, only represent 1%. Potassium comes in at 0.35% and then Sulphur comes in at 0.25%. Now it is worth noting at this point that of the eight elements I've just mentioned only, Carbon, Oxygen, Sulphur, Hydrogen, Nitrogen and Phosphorus are actually required for basic life to form. That's 99.1% of your body right there. The remaining 0.8% is made up of Sodium, Magnesium, Copper, Zinc, Selenium, Molybdenum, Fluorine, Chlorine, Iodine, Manganese, Cobalt, Iron, Lithium, Strontium, Aluminium, Silicon, Lead, Vanadium, Arsenic, Bromine. All in all 28 elements are required to create a human being. Now we're not trying to make a human being but I suppose we can assume that any other intelligent beings we might one-day meet will be at least as complicated. Now they may not use the same elements as us but they'll definitely need the six basics to get of the ground so lets start with those.

Hydrogen: There's a reason this reactive little bugger is the biggest game in town, and it all comes down to simplicity. Hydrogen consists of just one proton and one electron. Now the basic building blocks of atoms are called baryons and they came into existence within 3 minutes of the creation of the universe. Now it did admittedly take about 300,000 years for the universe to settle down enough for electrons to get added to the party. So Hydrogen's been floating around since shortly after floating and around were invented.

Carbon, Oxygen and Nitrogen: Now these elements are created as a result of fusion which takes place at the hearts of stars. Specifically in the hearts of Red Giant Stars however the elements are only released when the star transforms into a White Dwarf Star. Stars first started to form around 300 million years after the Big Bang.

Phosphorus and Sulphur: These are among the heavier and more complex elements that the universe can create, requiring as a birth place the heart of a super-giant, basically a star that had a large enough mass to survive past the white dwarf stage, about 8 times the size of our sun. The production of these elements happens after the Carbon fusing stage.

The first stars that formed in our universe were formed in the middle of a vast sea of hydrogen. The second they gained critical mass would have led to massive growth. Stars can have lifespan ranging from a few million years to a over a trillion years. While it's impossible to know the what exactly the happened to those first stars it is safe to assume some were of the burned bright and quickly. So all the elements needed to create life were around within roughly 300 million years of the Big Bang.

Life needs a home though, so we need to work out the availability of planets. Now I'm not going to waste time in this article with the Goldilocks Zone theory, because the earliest planets were either in it or the weren't and I'm talking about the possible rather than the possibly not. Studies of the red-shifts of incredibly distant stars have revealed that the same first generation of stars that gave us the elements for life, also created the conditions for the first solar abundances, the stuff planets form out of. It's estimated that planets could've shown up as early as the first billion years of the universes existence.

So lets template our own planet on to the top of one of these early ones shall we the earth is roughly 4.5 billion years old and life, in it's most basic form arose here around 4 billion years ago. So basic life could've been up and running on a distant rock around a billion years after the Big Bang or 12.7 billion years ago. Now it then took another 8 billion years for us to arise. So lets say that based on that timetable of evolution there could be life of an equal intelligence to our own 8.7 billion years ago. Would they have by now traversed the cosmos, ascended to new heights or plotted a course towards destruction? I don't know but there has been time for them to utterly dwarf us in every possible way.
I'm well aware that the chances of life evolving are slim, we've struggled through multiple extinction level events on Earth and there's no way of knowing if we are lucky or unlucky, but it does throw open the possibility that the universe out there is teeming with life, and that's a very beautiful possibility indeed.
"Two possibilities exist: Either we are alone in the Universe or we are not. Both are equally terrifying."
- Arthur C Clarke

Eddie <never enjoyed research so much in my life>

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