Date: October 18, 2011

Title: The Vital Importance of the Moon for Life on Earth

Podcaster: Damian Lima

Organization: Ciencia Limada

Link: http://www.ciencialimada.com.ar/

Description: In this podcast we are going to analyze the different reasons why the moon could be of vital importance for life as we know it on Earth, analyzing the formation of the first life forms, the influence of the moon in our climate and the favorable conditions for life on our planet.

Bio: Damian Lima is a passionate amateur astronomer and writer from Buenos Aires, Argentina. He works as Technical Engineer at a major Computer Software company. He also writes a blog on science, critical thinking and skepticism called “Ciencia Limada”.

Sponsors:This episode of “365 Days of Astronomy” has been sponsored by the Physics Department at Eastern Illinois University: “Caring faculty guiding students through teaching and research” at www.eiu.edu/~physics/

This episode of “365 Days of Astronomy” has also been sponsored by the Lake County Astronomical Society in northeast Illinois.

Transcript:

The Vital Importance of the Moon for Life on Earth

Hi everyone! My name is Damian, I’m an amateur astronomer and also an amateur writer from Buenos Aires, Argentina. I am going to talk about the great importance of our moon for life as we all know it on Earth.

From all the celestial bodies that we can observe from our planet, without any doubt our Moon is the one that most has captured the attention and imagination of all humans through history. In first place, for being the largest object in the night sky and the one that can be seen with greater level of detail with naked eye. But maybe there is a more important reason for which we should feel a deeper fascination to the moon: our own life.

Although it has not been proven whether or not life on Earth would have existed without the presence of the Moon, and most of the information we have is based on scientific speculation, if such life would have existed we rest assure that it would be very different from the life we all know. We are going to analyze the different reasons why the moon could be of vital importance for life as we know it on Earth.

The moon produces a physical effect over planet Earth, and it is the cause of the rise and fall of the tides. The moon’s gravitational pull exerted over the Earth produces a deformation on our planet, stretching it in those places where the pull is stronger, phenomenon known as “gravity gradient”. Since the Earth’s ground is solid, this pull affects more significantly the oceanic waters, generating a slight movement towards the moon, and also producing a less evident movement in the opposite direction; this is why the ocean’s level rise and fall twice a day.

Another important fact to keep in mind is that the Moon is gradually moving away from Earth, exactly at a rate of 3.8 centimeters, or one inch and a half, per year. This can be scientifically proven today thanks to the Laser Ranging Retro-Reflectors that Apollo mission’s astronauts left on the lunar surface, just firing a laser beam towards these reflectors and precisely measuring the distance. The importance of this fact is that if we go backwards in time, the moon would be more and more close to the Earth, reaching a point when, billions of years ago, the Moon must have been really close to our planet; so close that it could have been appreciated in the sky with enough level of detail to count even the smaller craters (so bad that in those times there was no humans on Earth to appreciate that spectacular show).

So, if we consider that the actual gravitational pull of the moon create the tides, even with the moon being so far away from Earth, then billions of years ago, when the Moon was so close to our planet, the tides produced in the interaction between this two bodies must have been really huge. Incredibly large waves of water would have covered hundreds of miles of the surface. If the tides of our times reach up to tens of meters high, in those early days that height would have been of tens of kilometers. The colossal waves of the early Earth would swept large areas of the ground, dragging in the process high amounts of minerals and chemicals into the ocean depths. This diversity of chemicals and minerals, agitated by the extreme tides, exposed to very high amounts of radiation and energy received from the sun, after millions of years of reactions and interactions, would have form a primordial soup of organic molecules. Once this molecules gain complexity, this would lead to the formation of amino acids, which are the main functional block of proteins, and these occupy a place of utmost importance among the constituent molecules of living organisms and play a key role in life.

In addition to the tides, there is another gravitational effect produced by the moon upon which the life on Earth depends: the Moon is responsible for maintaining stable the climate of our planet. The moon’s gravitational effect maintains constant the inclination degree of the rotational axis of the Earth, and this inclination is what keeps stable the season’s cycle as the Earth orbits the Sun. It can be demonstrated mathematically that if the moon hadn’t existed or had been much smaller, the slope of our poles would be very different and the inclination angle would be changed about 90 degrees. The actual inclination angle of the Earth is 23.5 degrees, and it remains unchanged over time. But without the gravitational force exerted by the moon it would vary chaotically, which could have devastating consequences to the climate and to the life on our planet. Our natural satellite has been, and still continues to be of crucial importance for the stability of the rotational axis of our planet, and consequently our climate.

Another important fact is that, as we all know, our planet rotates completely on its own axis once every 24 hours. But without the presence of the moon and its gravitational effect, the Earth would complete a rotation every 8 hours instead of 24, so one year on Earth would consist of 1095 days of 8 hours each. With a rotational speed as high as this, the winds would be much more powerful and violent than we know today, the atmosphere would have much more oxygen and the planet’s magnetic field would be three times more intense. Under these so different conditions, it is reasonable to assume that if plant and animal life would have developed, it would have evolved completely differently than it actually has. The 24-hour days in the rotation of our planet greatly favors the life forms that inhabit it, since the temperature variations are not too abrupt in the transition from day to night, as they would be in days of only 8 hours.

As we can see, there are a lot of conditions and events that must be met for advanced life forms like humans to develop on a planet. We have analyzed several reasons why the Moon, our traveling partner around the Sun, can be of vital importance for life on Earth. And these are only a tiny fraction of the huge number of conditions and factors that had to occur in a certain way so that today each of us can live their lives in this planet.

So next time you look up to the sky and see the moon majestically shining, keep in mind that the strong gravitational interaction that occurred in earlier times between the Earth and our spectacular natural satellite, might be one of the causes by which the inert matter present in our planet performed the necessary chemical process to become organic. And that the adequate stability of the gravitational force over billions of years provided our planet with the necessary stable conditions for that organic matter to organize itself, reproduce, evolve and get more and more complex so that, at the present times, the same organic matter may wonder about the multiple conditions and factors that had to be met for it to exist.

Thank you very much for listening this 365 days of astronomy podcast. Have a really great day and keep shining under the moon.

End of podcast:

365 Days of Astronomy
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