Knowledge Point 01: The Earth is Home to Millions of Species and the Only Known Celestial Body with Life
The Earth has nurtured millions of species, including humans, and is currently the only known celestial body in the universe where life exists. Born 4.54 billion years ago, life emerged subsequently and transformed the atmosphere to be suitable for aerobic organisms.
Detailed Explanation:
As a planet, the Earth has nurtured countless life forms throughout the course of cosmic history. From simple microorganisms to complex humans, the Earth boasts an astonishing number of species totaling in the millions.
This fact makes the Earth the only known celestial body in the universe where life exists. The Earth’s history dates back 4.54 billion years, with the emergence of life occurring slightly later. The birth and evolution of life not only changed the Earth’s atmosphere to be suitable for aerobic organisms but also had a profound impact on other environments.
The Earth’s biosphere is a complex and sophisticated system that supports the continuous existence and reproduction of life.
Knowledge Point 02: The Interaction Between the Earth, Sun, and Moon Determines Seasonal Changes and Rotational Speed
The Earth orbits the Sun once every 366.26 times its rotation, known as a sidereal year, and its axial tilt of 23.4° causes seasonal changes. The Moon stabilizes the Earth’s axial tilt and slows its rotation.
Detailed Explanation:
The Earth does not exist in isolation in the universe; it has close interactions with the Sun and Moon. The Earth orbits the Sun once every 366.26 times its rotation, a period known as a sidereal year.
Additionally, the Earth’s axial tilt of 23.4° results in seasonal changes on the planet. As the Earth orbits the Sun, the amount of solar radiation received by different hemispheres varies, leading to the alternation of spring, summer, autumn, and winter.
Meanwhile, the Moon, as the Earth’s only natural satellite, exerts a significant influence on it. The Moon’s stable existence not only maintains the Earth’s axial tilt but also slows the Earth’s rotational speed through tidal effects.
Knowledge Point 03: Earth’s Physical Characteristics and Orbit Determine the Periodic Continuation of Life, with Life Expected to Persist for Another 1.5 Billion Years
The Earth’s physical characteristics, geological history, and orbit collectively determine the periodic continuation of life. It is estimated that the Earth will continue to support life for another 1.5 billion years until the increasing brightness of the Sun leads to the extinction of the biosphere.
Detailed Explanation:
The Earth’s ability to support life and its periodic continuation is attributed to its unique physical characteristics, geological history, and orbit. The Earth’s magnetic field and atmosphere jointly provide protection for life, blocking harmful radiation from the universe.
Moreover, the Earth’s position and orbit in the solar system provide it with appropriate levels of light and temperature. These factors work together to enable life on Earth to reproduce and evolve.
However, scientists predict that within the next 1.5 billion years, as the brightness of the Sun continues to increase, the Earth’s biosphere will face the threat of extinction. This prediction reminds us to cherish and protect the Earth, our only home.
