Islands Islands are usually defined as portions of land surrounded by water, although it is true that continents would fit in this definition as well. However, they differ from these because they appear surrounded by water everywhere and by their dimensions, since they are much smaller.
Category Earth and Moon
The Earth and the Moon The Earth is our planet and, for now, we know that there is only life here. The Moon is the only natural satellite on Earth. If astronomy studies the bodies and phenomena of the Universe, there is no doubt that we have the first "raw material" for this study on our own planet, the Earth and (to a lesser extent) on the Moon.
Magnetism and electricity on Earth The Earth behaves like a huge magnet. The English natural physicist and philosopher William Gilbert was the first to point out this similarity in 1600, although the effects of terrestrial magnetism had been used much earlier in primitive compasses. The magnetism of the Earth is the result of a dynamic, since its iron core of the Earth is not solid.
Precession and nutation The previous page deals with the two most evident movements of the Earth, translation and rotation. This explains two other less noticeable, but equally important: precession and nutation. The spring and autumn equinoxes are not fixed, because the plane of the equator rotates in relation to the plane of the ecliptic.
Origin and evolution of the Earth This chapter summarizes the geological and biological history of the planet Earth in 10 pages, making a simple and educational journey through all the stages that go from its formation to the present. When talking about the origin of the Earth, there is little to say about what happened during the first two thirds of the evolution of the Universe, only that, at some point, a spiral galaxy was formed that we call the Milky Way.
Earth Movements Translation and rotation are the two Earth movements that determine the duration of days and years. Earth is in continuous movement. It travels, with the rest of the planets and bodies of the Solar System, rotating around the center of our galaxy, the Milky Way, which also does not stand still.
Earth maps The human being has always had the need to move from one place to another. Sometimes, in search of food, new territories or more benign climates. Others, to extend their commercial activities or seize territories and cities from other humans. Lately, travel for pleasure, on vacation, sightseeing.
Earth's crust Earth is one of the solid planets or, at least, solid crust, since not all layers are. If we make a cut that crosses the Earth through the center we will find that, under the crust, there are several layers whose structure and composition varies greatly. Above we have the atmosphere, a layer of gases we call air, formed in turn by a series of layers, which functions as a protective shield of the planet, maintains the temperature and allows life.
Earth: hydrosphere and atmosphere Astronauts always speak of Earth as "The Blue Planet", due to its color. And the photos captured from space prove it. Those responsible for having these blue tones are the oceans and the gases of the atmosphere, that is, the two components external to the earth's crust.
The mantle and the core of the Earth The Earth's crust is a very thin layer if we compare it with the mantle and the core of the planet. What is the earth's mantle? The Earth's crust is formed by more or less rigid plates that rest or float on a high temperature viscous material, called a mantle.
Geological history of the Earth From its formation until today, the planet Earth has undergone many changes. This is his story divided into Geological Eras. The first stages, from the beginning of the solidification of the incandescent mass until the appearance of a permanent crust, left no evidence of its passage, since the rocks that were generated, melted again or were simply "swallowed" by A new eruption.
The Paleozoic: Cambrian, Ordovician, Silurian This was ancient, the Paleozoic, lasted about 290 million years. The planet was very different from today. The Paleozoic era or Primary era belongs to the Phanerozoic eon. With the emergence of multicellular organisms, the Precambrian ended and began, about 541 million years ago, the Fanerozoic eon, which ended about 251 million years ago.
Continuous movement What has happened, at least once, can happen again. And it will happen. The movement of the plates that form the earth's crust sliding on a viscous layer, subject to strong tensions, cannot be stopped. Why don't we notice? Well, it's a very slow movement, or our vision very fast.
How was the Earth formed? The Earth we know looks very different from what it had shortly after its birth, about 4,470 million years ago. Then it was a mass of conglomerate rocks whose interior was heated and eventually melted the entire planet. Over time the bark dried and became solid.
Failures of the earth's crust Failures are a type of deformation of the earth's crust that ends in rupture, resulting in a wide variety of geological structures. One of the accidents of the terrain that can be observed more easily are these failures or ruptures of a folding, especially if the terrain is of sedimentary type.
The plates of the earth's crust The earth's surface, the lithosphere, is divided into plates that move at a rate of about 2 to 20 cm per year, driven by convection currents that take place under it, in the asthenosphere. There are seven large main plates in addition to other smaller ones.
The Paleozoic: Devonian, Carboniferous, Permian In the second part of the Paleozoic, the emerged lands are divided into two continents, Laurasia in the north and Gondwana in the south, which are dressed in green with huge forests of plants with seeds. At this time the expansion of life on the continents was consolidated.
Plate tectonics For billions of years there has been a slow but continuous displacement of the plates that form the crust of our planet Earth. This movement originates from the so-called plate tectonics, a theory that complements and explains continental drift. The continents unite with each other or fragment, the oceans open, mountains rise, the climate changes, influencing all this, in a very important way in the evolution and development of living beings.
Minerals and rocks Mineralogy is the science responsible for the identification of minerals and the study of their properties, origin and classification. The minerals appear with a wide variety of colors and structures, including types as diverse as vitreous black obsidian, jewel jasper, light and hard diamonds and soft, whitish talc.
The Mesozoic begins: the Triassic period This intermediate period in the geological history of the Earth lasted about 185 million years. The Mesozoic or Secondary Era is the time of terrible lizards, dinosaurs. The Mesozoic began 251 million years ago and ended 66 million years ago.