Quite Interesting – Water. Where does it come from?
This is probably my favourite section every month. You may think that you know everything that you could possibly want to know about water (as you did with the tomato last month) but I’m confident that you will learn something new with this and you’ll be utterly enthralled in the process!
How much water?
Firstly, and this won’t come as a surprise, we have a lot of water on our planet. Around 326,000,000,000,000,000,000 gallons or 332,519,000 cubic miles depending on what system you wish to use. Of which, around 30% falls from the sky over Swansea every day. Not true.
97% of this water can be found in our seas and oceans. The ocean makes up 71% of planet earth and its average depth is 3,688 meters. That level of water is utterly incomprehensible!
The remaining 3% is found in rivers, lakes, underground, ice caps and in living things – just like you.
As you know, sea levels rise and fall over time. During the last ice age around 20,000 years ago, the sea level was over 120 meters lower than we see today. That sounds a lot and it is, however it only transferred around 3% of today’s ocean water into ice.
Water cannot be destroyed, and we lose no water from planet earth, it merely changes state.
There is no life without water.
Absolutely every single living thing that we have ever found requires water to survive. From the tiniest organism to the largest of mammals (which is kind of obvious because it lives in water).
Not only that but all living things are predominantly made of water. Fish are 80% water, plants are between 80% and 90% water. Not only that but living things seem to appear wherever water is – more on this later.
Quick chemistry
Chemistry can be incredibly complicated and therefor very boring. This is very simple, and although it won’t be the most exciting think that you have ever read in your life, it is slightly interesting and relevant so bear with me.
Atoms like stability. Atoms are made up of lots of tiny little things but for this we just need to concentrate on the electron. Electrons are the coolest thing on the planet, and they behave differently when they are being watched!! (genuine, look into the slit experiment) and everything, absolutely everything depends on them. Without them nothing works but none of this is relevant.
Atoms are made up of rings around the nucleus, which is where the electrons live, and every atom has the same pattern to the number of electrons it can fit in each ring. To be stable, an atom needs to fill their outer ring of electrons so that there are no gaps. The first ring of electrons has space for two electrons and the second ring has space for 8. You with me? (there are further rings for heavier atoms, but we don’t need to go there).
Each chemical element (different types of atoms) has a different number of electrons – this is where they get their atomic number from. So, hydrogen (Atomic number 1) has 1 electron, helium has 2 etc.
Oxygen has 8. With two electrons filling the first ring (of two) and the remaining 6 electrons whizzing around the second ring. This leaves a space for two other electrons – remembering that the second ring has 8 spaces, and they really like to fill them all up!!
So, in deep space, when oxygen atoms meet up with hydrogen atoms, they invite a couple of hydrogen atoms to fill their remaining two gaps in their outer ring where we have (a compound) H2O – water. (2 hydrogen atoms consisting of one electron each and one oxygen atom with 8 electrons)
Early earth
I hope you have got this far, and I take personal pride in this article if you have. Water has never been created in a laboratory. It is technically possible, but it has never been done. Water may not, have also ever been created on earth naturally. The water that we drink, what makes us, that makes up the insane numbers within the ocean, was probably all created in space.
On some levels, this isn’t a surprise. Afterall, every atom on this planet has come from space (or created by god if you wish). Iron created in a star, gold in a supernova, so water coming here from space is not overly shocking.
Except that, water cannot have been here when the earth was created!
A while back I said that ‘we lose no water from planet earth’ and that is true today. Our atmosphere, our gravity and our temperature mean that water, ice, or water vapour cannot escape our beautiful planet. However, 4.5 billion years ago, it wouldn’t have lasted a minute!
Imagine the earth being created (without the god bit). Huge collisions as masses of rocks collide to create a larger and larger planet. Impact after impact, one being so great that it broke off a large section that orbited around us for ever more (something we like to call the moon).
At this time, it is thought that the top-of-the-atmosphere temperatures were upward of 3,600 degree Fahrenheit. Magma would have flown on the surface like our oceans do today. Water could not have remained here. Once cooled and calmed, we had a dry planet.
So how did water get here?
If it can’t be easily created and it wasn’t here when the earth was in its very early days, then how do we have so much water on our planet now?
It’s a question that no scientist can answer with any certainty. There isn’t yet a proven theory that has no flaws. What is commonly accepted though, is that the bombardment of objects from outer space on our planet didn’t stop then.
One type of object that hits our planet that we know contains water are Comets. Could they have brought the vast oceans to us?
It was a theory that was so convincing that the European Space Agency (ECA) sent a rocket (Rosetta) to track a passing comet in space. Not only that, but the ECA successfully landed a robot (Philae) onto the comet to analyse further.
Water was extracted from the ancient space object with the aim of finding out whether this could be the answer to our dilemma. It seems fitting to put a Wallace (and Gromit) voice on here and say that it was the ‘wrong water Gromit!’.
The mission was a success in as much as it came back with a result – however the result was that ‘at most, 10% of Earth’s water could have originated on a comet’. The ratio of normal water to heavy water (which is water made from deuterium – that is like hydrogen but contains a neutron) was different to that on Earth. Comets were not the answer.
The most common thing to hit our planet are meteorites. We are hit with over 40 tons of meteorites every day which is why most scientists think that these meteorites are behind our oceans – especially when some contain as much as 20% water.
It is worth remembering that we know that Mars had water. It is probable that some moons within our solar system do too. It is abundant in the universe. So, the rocks and comets smashing into everything around us are the obvious vessels of water.
However, even with the huge volume of meteorites and over 4 billion years of impact, there still doesn’t seem to be enough water to create what we see. There are also issues again with the heavy water to normal water ratio – the question remains unanswered.
Life on mars?
At the very least, it seems inevitable that some of the water that we see, drink and are made of, are from comets and meteorites. It has also been suggested that solar winds could have brought some water along the way too.
In the dictionary the word extra terrestrial means “any object or being beyond (extra-) the planet Earth (terrestrial)”. There is no timescale to the definition. The earth itself is created beyond planet earth. You are made of star-stuff.
So, let’s date the definition. I’d assume that most would agree that the true meaning would imply ‘from when Earth was created’. Yet, even if we use this then it leaves a very blurry line. When the earth was created, heavy metals (like gold) sank to the core. The gold that we use is almost all from asteroid impacts long after earths creation and therefore is extra-terrestrial.
Then we have you. You are 60% water. We don’t know for certain how much of that water was here when the earth formed but we know for certain that some is extra-terrestrial.
Then we get to the big question. If, a large quantity (or maybe even all) the water that we have on earth is extra-terrestrial and that water is the gift of life, then why do we assume that the life we have on this planet began on this planet?
If comets and asteroids are spreading water all over the universe, then could they not also contain the origins of life on these vessels? Some scientists argue that it’s not only possible but probable. This being the case, then not only is it inevitable that life is abundant in the universe wherever there is water (which is a lot of places). But also, that those beings are related to us.
All living things on this planet share certain DNA that suggests that all life that we know has evolved from one organism. If that organism wasn’t created here, then the ‘aliens’ on other planets are no more alien than you.
