The Origins of Water and Carbon Dioxide on Earth

To ask what 'delivered' water and carbon dioxide to Earth is to assume that Earth existed without these essential components at some point in time. However, there is no evidence to support such an assumption. The presence of these elemental compounds is consistent with the understood geological and atmospheric processes that have shaped our planet over billions of years.

Geological Evidence from Jack Hills

Jack Hills in Australia contains some of the oldest known volcanic formations, dating back to 4.666 billion years ago. These volcanoes release carbon dioxide, and the granites and zircon crystals found there can only form under aqueous conditions. This implies that water was present at the time of these formations. The existence of these ancient formations and geological structures further supports the idea that water and carbon dioxide were not delivered to Earth but were present from the very beginning.

Life and the Earliest Evidence

The concurrent strata at Jack Hills also reveal the presence of stromatolites, which are ancient formations created by living organisms. These stromatolites provide evidence that life existed on Earth from a very early stage. Stromatolites as old as 3.5 billion years have been discovered, indicating that biological processes had started by that time. These early life forms played a crucial role in the cycling of water and carbon dioxide, contributing to the early atmosphere and possibly even aiding in the formation of the first oceans.

The Formation of Earth and Its Elements

Earth is composed of elements that are in the same proportions as those found in meteors, asteroids, and other planets. The planet itself formed from the debris of these other celestial bodies, often referred to as 'meteors.' This accretion process suggests that the basic chemical composition of Earth was set in its early stages, with water and carbon dioxide being part of this composition from the outset.

The Moon and Its Influence

Of note, the Earth’s moon plays a significant role in maintaining conditions that favor life. The moon, being the fifth largest moon in the solar system, influences the Earth’s gravity, leading to various geological and meteorological phenomena. The moon’s gravitational pull helps in the tides, which are crucial for coastal ecosystems, and also contributes to the overall stability of the Earth's axial tilt, keeping the climate relatively stable.

Continuous Cycles of Water and Carbon Dioxide

Water and carbon dioxide have been present in the gas and dust cloud from which the solar system, including Earth, formed. This means that water and carbon dioxide have existed on Earth from its inception and played a crucial role in the development of life. As life evolved, the relative levels of these gases began to change. Plants began to use them to produce sugars, starches, and cellulose, while animals and plants use sugar, starch, and cellulose back into water and carbon dioxide during respiration at night.

Conclusion

The presence of water and carbon dioxide on Earth is a fundamental aspect of its geological and biological history. From the earliest formations to the ongoing processes of life, these elements have been integral to the planet's development and maintenance. Understanding the origins and cycles of these compounds is crucial for comprehending the overall geology and biology of our planet.