The Delicate Balance Needed for Life on Earth
1. The Right Distance from the Sun
Did you know we are just the right distance from the sun? If we received 1% more heat energy from the sun it would be too hot. Just 1% less and it would be too cold.
Earth's 93 million-mile-average distance from the Sun (typically referred to as one astronomical unit or 1 A.U.) allows our planet to have an ideal surface temperature of 58 degrees Fahrenheit and an average ocean-water temperature of 45 degrees Fahrenheit. In fact, in terms of insolation (i.e., incoming solar radiation), this orbital radius positions our world at the optimum location for life in the entire solar system.
2. The Size of the Moon and our Distance from It
If the moon was significantly closer or bigger, we would have devastating tidal waves. If it was significantly smaller or farther away, the oceans would stagnate along the coastlines.
3. The Thickness of the Earth’s Crust
The ultra-thin outer layer of our planet - the crust - is just the perfect thickness for the right amount of gravity to hold our atmosphere, etc.
4. The Earth's Mass
Our mass is just enough to keep a thin layer of gases above us. Any more mass (more gravity) means a heavier, more destructive atmosphere with more deadly gases staying here. If we have less mass (less gravity), we couldn’t hold onto oxygen and other life-support gases.
5. The Earth's Ozone Layer
The thin invisible ozone layer keeps us alive by absorbing nasty radiation from space. If we have less ozone - we roast in UV light from the sun; any more, and we don’t get enough of the sun’s life-giving energy through to the surface.
6. The Amount of Oxygen in Our Atmosphere
Oxygen, a gas that is vital for living beings, helps food to be burned and converted into energy in our bodies. If the oxygen quantity in the atmosphere were greater than 21%, the cells in our body would soon start to suffer great damages. Fire would burn out of control. The vegetation and hydrocarbon molecules needed for life would also be destroyed.
If this quantity were less, then this would cause difficulties in our respiration, and the food we eat would not be converted into energy. Therefore, the 21% oxygen in the atmosphere is the most ideal quantity determined for life.
7. The Amount of Nitrogen in Our Atmosphere
Nitrogen is arranged in the ideal quantity for the needs of living beings and the continuity of life. The amount of nitrogen in the atmosphere has the ideal ratio to balance the harmful and burning effects of oxygen. This ratio represents the most appropriate value required for photosynthesis, which is essential for life's energy supply on the earth.
8. The Amount of Carbon Dioxide in Our Atmosphere
The amount of carbon dioxide has the most appropriate value that is needed to maintain the stability of the surface temperature of the earth and to prevent heat loss especially at night time. This gas, comprising 1% of the atmosphere, covers the earth like a quilt and prevents the loss of heat to space. If this amount were greater, the temperature of the earth would increase excessively, causing climatic instability and posing a serious threat against living beings.
9. The Amount of Vegetation on Earth
The vegetation covering the earth converts carbon dioxide to oxygen, producing 190 billion tons of oxygen every day. The proportion of other gasses is always kept constant on the earth by the help of interconnected complex systems. Life is thus sustained.
10. The Importance of Water
It is necessary for all life forms. 70% of the earth’s surface is water. 60% of the human body is made up of water. Water will dissolve almost anything. Minerals and chemicals must be dissolved before they can be taken in by plants.
11. The Tilt of the Earth's Axis
The axis of the earth is tilted about 23.5 degrees with respect to the plane in which the earth orbits the sun, so we experience a variation of seasons each year. In the northern hemisphere summer, the North Pole is tilted towards the sun, so the sun is higher in the sky and the days are longer than the nights. At the same time the southern hemisphere is experiencing its winter. The reverse is true six months later. When the sun passes through Earth’s equatorial plane, the days and nights are of equal length. This is called equinox and occurs in late March and late September.
The variation of seasons is vital for many forms of life to thrive. The annual cycle of cold to warm seasons regenerates plants and animals and serves to measure the passing of time with variety in the weather conditions around us. The warmth of summer gives way to the glorious colors of autumn, then to the repose of winter followed by the explosion of new life in the spring.
12. The Rotation of the Earth's Axis
If the earth had completed one revolution every 30 hours, such tremendous winds would have ensued that the earth would have become a hurricane-ridden desert for living things. If, on the contrary, the earth had rotated every 20 hours, most plants would have been unable to complete their biological activity and fallen victim to droughts.
The rotation of the earth helps to regulate the temperature around the globe so no one part becomes too hot or too cold. If the earth were tidally locked to the sun, as the moon is to the Earth, one side would be permanently facing the sun, and would be searingly hot, with the other in permanent frozen darkness.
13. The Earth's Ecosystem
Scientific research to date links the chain of life to the balanced interactions between plants, animals and bacteria. The bacteria are charged with transferring nitrogen from animals to plants. Plants produce the oxygen needed by animals and other organisms, and animals supply both carbon dioxide and–through bacteria–nitrogen to plants.
14. The Cleansing of the Ocean Tides
The ebb and flow of Earth's tidal circulation (in response to the lunar gravitational pull) purifies the world ocean and the continental shorelines which serve to enclose its waters.
15. Earth's Orbit
Planet Earth moves in a nearly perfectly circular orbit in what is called the circumstellar habitable zone around the sun. This zone is where liquid water can exist so it is not too hot, to prevent all the water from boiling away, and not too cold, to prevent all the water from freezing solid.
16. Orbital Speed and Duration
With an orbital period of exactly 365.256 days, which the Earth can accomplish by racing through space at an incredible 66,600 mph (over 18 miles/sec !!), our planet's seasonal length is conducive for agriculture.
These are called parameters. Some have estimated there may be as many as 200 of these parameters needed to support life on a planet. Throw them off much at all and we can’t live here.
It appears that for humans and our civilization to even exist requires the planet, the solar system, the galaxy - the universe! - to behave perfectly, and in unison!
