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Language:English 英文
【Maintaining Energy Balance - Part 2: Earth and Life 维持能量的平衡下编-地球生命编】
What is the meaning behind the universe's arrangement of all this? Perhaps the continuation of life and civilization is the answer. As human beings, we should take on the role of guardians of Earth's civilization, and protecting the continuation of the millions of lives on Earth is the best way to show gratitude.
The early Earth: an energy contest between molten lava and cooling (4.6–4.0 billion years ago). In the solar system's protoplanetary disk, planetesimals formed the proto-Earth through collisional accretion, converting kinetic energy into thermal energy, with surface temperatures exceeding 1,200°C, creating a global magma ocean. Dense iron and nickel sank toward the center, releasing gravitational potential energy (about 10³¹ joules) and further heating the interior. Lighter silicates rose and gradually cooled to form the primordial crust. Long-half-life elements such as uranium-238, thorium-232, and potassium-40 decayed, providing a long-term heat source (still contributing about 50% of geothermal heat today). Mantle convection transported internal heat to the surface, and volcanic eruptions released excess energy, preventing overheating and complete melting. Earth achieved a dynamic balance between radiative cooling (Stefan–Boltzmann law) and internal heat production (radioactive decay), avoiding becoming a dead, rocky world. Volcanic eruptions released H₂O, CO₂, N₂, CH₄, NH₃, etc., forming a reducing atmosphere. Some water may have been delivered by impacts from water-rich meteorites (such as carbonaceous chondrites). High concentrations of CO₂ and CH₄ maintained surface temperatures, preventing the oceans from freezing (the early Sun's brightness was only 70% of today's), sustaining a greenhouse balance. Seawater dissolved ions from volcanic rocks (e.g., Na⁺, Cl⁻), initiating geochemical cycles.
About 4.5 billion years ago, a Mars-sized body struck Earth at an oblique angle, ejecting material that formed the Moon, and the tilt of Earth's axis triggered seasonal changes. The Theia impact released 10³² joules of energy, reshaping the mantle structure and accelerating core differentiation. After the magma ocean cooled during the Hadean eon, basaltic and granitic crusts gradually differentiated. Local mantle convection initiated early tectonic activity, but not a modern plate tectonic system. Liquid water, the atmosphere, and chemical gradients formed an "energy ladder," providing a reaction medium for subsequent molecular evolution. Volcanic vents and deep-sea hydrothermal systems became arenas for abiogenic synthesis (e.g., iron‑nickel sulfides catalyzing the formation of organic molecules). The early Earth's molten lava and cooling set the stage for the next step — "chemical reactions." In the boiling oceans and an atmosphere crackling with lightning, energy would give rise to ever more complex molecules, ultimately moving toward...
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