Romantic verse and werewolves aside, the Moon is, in fact, far more interesting than you would imagine! We are all very guilty in that we take it for granted as it’s just there, hanging in the sky all the time. We appreciate its beauty and how handy it is as a nightlight. However much lovers, lycanthropes, and poets may rely on its silvery light, you have to wonder what life would be like if it was not there. Would there even be any life? Particularly, life as we understand it. As always, we need to take a journey into the past.
The formation of our Solar system was by no means a sedate or gradual process, it was quite violent! There were many, many collisions the evidence of which we can still see today. Craters are commonplace, but far bigger impacts were also common: Venus is rotating very slowly in the wrong direction with evidence of global volcanism. Uranus shows us its backside; as its axial tilt is just over 90 degrees, it rotates on its side. Both of these odd properties are presumed to have been due to impacts when planetary embryos regularly reinvented themselves, including the formation of our Moon.
The prevailing theory is one known as ‘The Big Splat‘, essentially, another planetary body approximately the size of Mars cannoned into the baby Earth causing most of its mass to merge with the Earth, including its iron core (explaining the Moon’s low iron content). The bits left over eventually coalesced into the Moon. There is, naturally much speculation over what exactly happened.
At this time, about 4.6 billion years ago the Moon was much much closer to the Earth than it is now. This means that the tidal forces due to the its influence would have been much stronger. Earth had oceans very early in its lifecycle, so the tides will have been immense. These extreme tidal forces may have even triggered plate tectonics which recycles the Earth’s crust and keeps our temperature in equilibrium. It is an intruiging possibility that the original impact may have been responsibile for this. This tidal friction as we call it would have also slowed down the Earth’s rotation. Back then, our planet would have been whizzing around with a 5 hour day/night cycle rather than the 24 hour cycle we are accustomed to. Another major consideration would be Earth’s axial tilt, which has held steady at 23 degrees, unlike Mars which wobbles chaotically. This tilt is also responsible for our seasons. The original impact may have also enriched the Earth’s liquid iron outer core to help produce the strong magnetic field that helps defend us from highly charged particles that could strip away our atmosphere.
If we had no Moon? What would happen then? Well, it would be darker at night, but astronomers would have a great view of the skies. Would we still have tides? Yes, the gravitational effects of the Sun also produce tides, but they would be around 40% weaker. We would have much shorter days and nights without the cumulative effect of tidal friction. This quick rotation would cause violent winds and storm systems. If our axial tilt was as chaotic as as Mars’ we could have ice at the equator quickly followed by desert. Chaotic seasons would cause extreme climate fluctuations over a relatively short period of time.
Our next question is of course, how would the lack of our Moon affect the emergence of life on Earth? If, as we currently believe, life began around deep ocean vents, a moon isn’t strictly neccessary. However, if you think about Earth’s fast rotation and the huge tides way back when, this would throw up chemicals that could concentrate eventually into protonucleic acids. These acids would then be swept back into the oceans and eventually assemble into RNA and other building blocks of life. Would the Sun’s tides be strong enough to have the same effect? It is not impossible, though the process would occur more slowly. As for axial tilt, there are ways for it to remain stable without the Moon’s influence, although it undeniably helps. All in all, life, and even humans, could still have evolved. There is little doubt that the process would be quite different and possibly the outcome. If the Moon disappeared tomorrow, it would not be a total disaster, we would adapt. If nothing else, we would be free of the threat of werewolves.
It has been theorized by some that that our Moon’s serendipitous characteristics, its unusual size, formation time, formation method, and stabilizing effect, must make us important. Does this mean that having a big, fat moon is an essential requirement for life to form? It would neatly solve the Fermi paradox, which states life should be everywhere and why the Drake equation must be wrong or amended in a way that drastically reduces the possibility of life emerging elsewhere. That we are in some way ‘special’, or that its all far too coincindental. On the other hand, Europa is a moon, does not seem to require one of its own, has more water than Earth, and appears to be the likeliest place to find life elsewhere. Complex life though, is more problematic and there are far more questions than answers at this point in time.
It is nice to have the Moon, it has also certainly helped science immensely to study our closest celestial neighbour. We have only just started on our journey to explore what is out there, I think it would be foolish not to have an open mind about the surprises we will doubtlessly find.
This article originally appeared on TheMittani.com, written by Feiryred.