Taken for granted -- Take 1: Earth's exact mass

Fish in the ocean are probably unaware of the miracle of the waters surrounding them. Do we as humans take the miracles of life and the creation surrounding us for granted?

My purpose in this series of posts is to identify several of the many miracles we take for granted, without which we would cease to exist. Is this by chance, or by design? You be the judge.

There are at least 150 requirements for life to exist on the earth. As you add the requirements for life to exist on this planet, the probability of life occurring randomly decreases dramatically as you multiply those probabilities together. How dramatically, we will see, and even if life is possible considering the earth’s age of 4.5 billion years.

Let us explore the first miracle…

The earth’s mass is 5.972 x 1024 kg; otherwise, life on earth ceases to exist!

The atmospheric gases of methane (atomic mass 16 or amu 16), ammonia (atomic mass 17 or amu 17) and water vapor (atomic mass 18 or amu 18) are as close to each other in weight as you can get and are all transparent gases in our atmosphere.

If the earth were slightly heavier, the poisonous gases of methane and ammonia would remain nearer the surface of the earth and kill human and animal life. Since the earth mass is precise, these gases harmlessly rise into the atmosphere to where they cannot be inhaled in toxic concentrations.

If the earth were slightly smaller, water vapor would escape into the atmosphere like methane and ammonia do. Water (amu 18) at normal temperatures and lower pressures would cause the oceans to boil and evaporate into the atmosphere like ammonia (amu 17) and life without liquid water would prove challenging..

Because the earth mass is 5.972 x 1024 kg, poisonous gases like methane and ammonia rise safely into the atmosphere away from animal and human life, fertilizers from the nitrogen cycle provide food for plant life, and the Hydrologic Cycle provides clean water so that plant, human, and animal life can exist on earth. If the earth’s mass were different, plant, human, and animal life would not be able to survive.

What are the chances that the earth’s mass is what it is?

In 2013, a team of scientists at Berkley estimated there to be 50 billion planets of similar size to the earth and 400 billion stars in the Milky Way galaxy. Size does not mean the same mass as density could differ – some could be gases. In our solar system, four out of eight planets are considered gas giants: Jupiter, Saturn, Uranus, and Neptune, and the densities of the planets vary significantly. Earth is the only planet with density of 5.51 g/cm3. Using this small sample of our solar system and extrapolating to the Berkley study, only 6.25 billion planets (1/8*50) would have the same mass as earth’s in a galaxy of 400 billion stars, or 6.25/400 probability of occurrence.

This is very optimistic since if planet formation is random, the differing masses of the orbiting planets could be infinite and corresponding probability of being equal to the earth’s mass significantly less than a 1 in a million. However, let's use the optimistic number of 6.25/400 for our calculations for the Base Case solution. Lets assume a 1 in a million chance, or 0.0001%, for a more realistic probability. We will see in a future post in this series what happens to this probability as we add requirements for life to exist on earth …

In conclusion: The chances of the earth's mass being equal to 5.972 x 1024 are very small, less than 1 in a million to high of 1.6%. Let’s not take the earth’s mass for granted and feel grateful today that the earth’s creation is exact and enjoy this with a few deep breaths of clean air.

The Scientific detail for those interested…

atomic mass unit (amu) = 1.66 x 10-27 kg

Consider Newton’s law of universal gravitation below:

F = G*m1*m2/r2

Where:

F = gravitational force

G = gravitational constant

m1 = mass of object 1, in this case mass of the earth 5.972 x 1024 kg

m2 = mass of object 2, in this case the molecular weight of the gas

r2 = distance between the centers of the objects

Methane CH4 = 1*12 + 4*1 = 16 amu

Major natural sources of methane include emissions from wetlands and oceans, and from the digestive processes of termites. Sources related to human activities include rice production, landfills, raising cattle and other ruminant animals (cow burps!), and energy generation.

Ammonia NH3 = 1*14 + 1*3 = 17 amu

Ammonia is a colorless, poisonous gas with a familiar noxious odor. It occurs in nature, primarily produced by anaerobic decay of plant and animal matter. Ammonia is a product of the nitrogen cycle, by which nitrogen in the atmosphere is converted into ammonia and then fertilizer which the plants can absorb for food. Without this process of nitrogen fixation, plants could not exist on earth, and hence humans and animals without food would die.

Water H2O = 2*1 + 1*16 = 18 amu

Water vapor can be produced from the evaporation or boiling of liquid water or from the sublimation of ice. Water vapor is transparent, like most constituents of the atmosphere. Under typical atmospheric conditions, water vapor is continuously generated by evaporation and removed by condensation. This Hydrologic Cycle of evaporation and condensation is critical to life on earth as it in the only way nature can purify salt water in the oceans for mammals and plant life to exist.