The main reasons for understanding the ocean from space are:
1. The ocean occupies most of the Earth's surface, making it difficult for humans to directly make comprehensive observations. The spatial perspective gives humans a broad perspective and helps us better understand the ocean as a whole.
2. Various ocean phenomena, such as ocean currents, waves, tides, etc., can be observed and studied more intuitively in space.
3. Space can provide global ocean data, which is of great value for studying marine environmental conditions, climate change and predicting natural disasters. For example, through satellite observations we can understand seawater pollution levels, sea level rise and the melting of polar glaciers.
4. Oceani informationThe data obtained from space can also be used to study the topography of the seabed, the geological conditions and geological processes of the seabed, as well as the distribution and utilization of minerals and biological resources of the seabed, etc. of great importance for the development of the maritime economy.
Therefore, understanding the ocean from space is of great importance for us to understand and protect the marine environment, understand climate change and develop marine resources.
Our story takes place in the Milky Way 4.5 billion years ago. Huge amounts of dust and asteroids orbited the early Sun. These rotating materials range from tiny dust to asteroids several hundred kilometers in diameter. Soon, materials large and small began to collide. Initially, the collision wasIt was slow and gravity combined the broken space materials to form a rocky body, which was the prototype of Earth. As more and more colliding objects gather together, the Earth gradually grows larger and its gravitational field becomes stronger and stronger, causing the surrounding interstellar material to be pulled toward the Earth faster and faster, with greater force. strong impacting the Earth's surface, forming huge craters and. giving off a lot of heat. Under the influence of intense heat, the outer layers of the Earth began to melt, forming a shallow sea of boiling lava. A huge amount of heat is also absorbed by the Earth's interior, buried under tons of growing rock. This process continued for millions of years until Earth reached its current size.
Early in Earth's growth, huge interstellar collisions were occurring rregularly, releasing large amounts of dust into the atmosphere, blocking all sunlight and plunging the Earth into total darkness. Comets, massive amounts of solidified gas and ice, and asteroids strike the Earth, and violent storms rage across the Earth. Large explosions resulting from huge impacts and ongoing volcanic eruptions release water and gases buried in rock into the atmosphere. The atmosphere at that time was in harsh conditions and very dense, composed of carbon dioxide, water vapor, nitrogen and several other gases. Black clouds of dust, steam, and volcanic ash enveloped the sky, violent thunder and lightning pierced the darkness, and a sea of blazing magma boiled and stirred on the ground. The darkness of the early Earth made it impossible to imagine that it would become a blue planet.
How do we know this all happened ages ago?about 4.5 billion years? Scientists have used a new technique to estimate the date of Earth's birth: radioactive dating. Everything on Earth's elements have certain atomic weights due to the different number of neutrons and protons in their nuclei. Some elements, such as uranium, radium, potassium, and carbon, have several different forms of expression due to the different numbers of neutrons in the nucleus of the same element, called isotopes of the element. Although isotopes have different atomic weights, their chemical properties are the same. Some isotopes are unstable and radioactive. Radioactive isotopes decay at a certain rate, called a half-life. The half-life of an element is the time it takes for the element to decay to half its original mass. If geologists know the half-life of an element, they can calculate the age of the rock by measuring the masses of the elements.parent and daughter elements (the products of disintegration). For example, carbon has three isotopes: two are stable (carbon 12 and carbon 13) and one is unstable, which is radioactive (carbon 14). When carbon-14 decays, it releases heat and produces nitrogen-14. The half-life of carbon-14 is 5,570 years, which means it takes 5,570 years for half of the carbon-14 to of a substance is converted to nitrogen-14. Geologists can estimate the age of a rock by measuring the amount of carbon-14 and nitrogen-14 present in the rock. This is called carbon dating.
Scientists believe that meteorites are the same age as Earth. By radioactively dating the meteorites, they concluded that the meteorites are 4.5 billion years old. Scientists now believe that Earth was hit by a huge asteroid early in its formation, causing part of the Earth to break off and form the Luborn. All lunar rocks are just under 4.5 billion years old. Dating of rocks from ancient craters, particularly those on the lunar surface, suggests that around 4.5 billion years ago, when Earth had reached its present size, the frequency of comet impacts and of asteroids began to slow down.
4.4 billion years ago, reduced impacts caused magma ocean activity to weaken and the Earth's surface began to cool. Slowly, the condensed magma formed a thin black crust covering the Earth. Although planetary impacts and volcanic eruptions sometimes tore apart the Earth's crust and released hot magma into the sky, as impacts continued to diminish and cooling continued, an increasingly thick crust formed. on the surface of the Earth. Cooling causes condensation of the water vapor present ins the atmosphere and water droplets fall to the ground as rain. Soon, heavy rains washed the land and formed the first ocean of water. The sea water at this time is acidic and very warm, with a water temperature of around 100°C. Volcanic eruptions and heavy rains bring elements into the ocean, making it slightly saltier. The atmosphere surrounding Earth is still full of carbon dioxide and is dense and corrosive. As condensation forms, sunlight begins to penetrate the dark clouds. At that time, high craters rose around the sea, but the eroding power of the water was enormous. Fierce floods flowed out of deep valleys and eroded mountain peaks. Several recent asteroid impacts have created huge waves in the oceans and tsunamis have swept across Earth. Because the Moon was closer to Earth at that time, tides in the oceans supportedstrong.
Carbon dioxide in the atmosphere begins to dissolve in the ocean, and carbon dioxide in the ocean begins to dissolve in the ocean. The ions combine to form calcium carbonate or limestone. As more limestone was deposited on the ocean floor, carbon dioxide in the atmosphere gradually decreased and the sky became brighter. Calcium carbonate regulates the acidity of the ocean, making the chemical environment of the ocean slightly bitter, acting like antacids taken by people suffering from hyperacidity. Increased solar radiation raises the earth's temperature, evaporates large amounts of ocean water, lowers sea levels, and exposes many land masses. As rain and river weathering carried more minerals from the new lands to the ocean, the salinity of the ocean began to increase.
During this period, Earth's climate changes may have been extremely dramatic, while volcanic eruptions, earthquakes, and tsunamis continued to transform the Earth's surface. Some scientists believe that during this period, catastrophic asteroid collisions still occurred from time to time and oceans continued to evaporate and transform in decades-long cycles.