Third From the Sun. A Few Words About Our Planet.

April 8, 2024
1:24 pm

Earth - the word is familiar to everyone. Everyone uses the word every day, in different meanings. The term 'Earth' is so universal and understandable that when we talk about the Earth, each of us knows what the other person means. But what is the Earth really? When was it created? How was it created? How old is it? What is our Earth made of? These are important questions to better understand what our planet is. It is home to hundreds of thousands of species of plants, animals and other living organisms - including us humans. It is therefore important for each of us to have a basic knowledge of our planet.

When was the planet Earth formed? Determining the age of planets is relatively difficult and requires a team of qualified experts. There are several methods for determining the age of planets, including the Earth. The first is the so-called radiometric method, which is based on the study of isotopes, i.e. products of the decay of a given element into other elements. In the case of the Earth, lead isotopes formed from the decay of uranium particles are studied. Another method is the analysis of meteorites that fell to Earth in the early stages of the development of our solar system. This method is based on the study of radioactive isotopes contained in meteorites, which makes it possible to estimate the age of the Solar System and thus limit the maximum age of our planet. Another method is dating based on cosmic radiation. In short, this method investigates how long and when rocks that are today hidden deep beneath the Earth formed the surface of the Earth, thus being exposed to cosmic radiation. Based mainly on these methods, scientists were able to determine that the Earth is about 4.54 billion years old. From our point of view - that's a lot. From the point of view of how old the universe is, it's not much.

Now that we know when the Blue Globe was formed, the question must be asked: how? Well, our planet was formed through a process known as accretion. What is accretion? Accretion is the gradual accretion of matter under the influence of strong gravity. In the context of planet formation, accretion occurs in areas of space where there is a large amount of dust and gas surrounding newly formed, young stars. Generally speaking, it involves very small particles of matter, under the influence of some external force (in this case, gravity), gathering at one point and combining to form larger structures.

Another important question: what is planet Earth anyway? It is the third planet in our solar system. Our globe is the only planet known to mankind at this time on which such diverse biological life exists. The planet we live on is in fact one large ecosystem made up of biotopes (habitats inhabited by different groups of organisms) ranging from oceans to forests to deserts. From a geological point of view, our planet is a highly complex system made up of three main layers: starting from the outside, we have: the crust, the mantle and the Earth's core. The Earth's crust is built up by two layers: the lithosphere (solid layer) and the asthenosphere (plastic layer). Both of these layers are quite thin, obviously from a geological point of view. The Earth's mantle is a very thick layer, which consists mainly of magmatic rocks (e.g. granite or basalt). The nucleus, on the other hand, is divided into an outer nucleus (the liquid part) and an inner nucleus (the solid part). Obviously, geological processes are continually taking place on and within our planet, resulting in constant changes in the landscape, both the one that surrounds us and the geological one, which we are not always able to see with the naked eye.

Nor must we forget what remains invisible to us, but without which we would not be able to live on Earth, namely the atmosphere. The Earth's atmosphere is made up of 99% oxygen and nitrogen. The remaining one per cent is made up of other gases (argon, neon, carbon dioxide). The atmosphere is also made up of layers. It can be divided into: troposphere, stratosphere, mesosphere, thermosphere and exosphere. The troposphere contains most of the atmospheric mass and is where weather processes take place. The stratosphere is the area that filters harmful ultraviolet (UV) radiation through the ozonosphere (ozone layer). The mesosphere, on the other hand, is where the atmosphere begins to thin. The thermosphere, on the other hand, is the area that intensely absorbs energy reaching us from the sun, resulting in an increase in temperature. The exosphere, on the other hand, is the layer that borders space. The atmosphere is very important because it protects life on Earth by absorbing and scattering solar radiation, maintaining the right temperature and filtering out harmful radiation arriving from different corners of space. Atmospheric gases are also responsible for regulating biogeochemical cycles and influence weather conditions.

Although we have already explored many aspects of our planet, it still holds some secrets. We still haven't fully explored the ocean environment, we are still discovering new species of previously unknown living organisms, archaeologists periodically come across new finds and settlements left by man centuries ago. Planet Earth is in fact the largest history book known to man and also the most accurate. It is estimated that the knowledge we have about our planet is roughly 5-20% of what we could know. So as much as about 80-95% of what is happening on our planet in all possible areas remains unknown. This shows how much we still have to learn and understand about our planet.

Let us now ask ourselves another important question: will the Earth exist forever? Well, probably not, unfortunately, because it is likely that even the universe will end one day. So what will the end of our planet look like? Scientists do not yet know one definite answer to this question. Several different scenarios are envisaged: the destruction of the Earth could be brought about by a collision with some cosmic object, climatic catastrophes, supernovae or any kind of geological catastrophe. There are also theories that say that with the end of the life of the Sun, life on our planet will also end. Another theory is that, before the Sun dies, it will grow to such an extent that the planet Earth will be engulfed by it and thus literally melt. And it is not at all impossible that all the scenarios described above will coexist. Unfortunately, for the time being we do not have the knowledge to identify the actual and, more importantly, the real cause of our planet's death.

Here we will give ourselves some interesting facts about our home planet Earth:

Earth is the only planet in the solar system where life exists in significant numbers.
At the centre of the Earth is a very hot iron core, which generates a magnetic field that protects our planet from cosmic radiation.
The still ocean is the largest ocean on Earth and occupies 46% of the surface of all oceans.
The first life appeared on Earth about 3.5 billion years ago.
The Earth orbits the Sun at an average speed of 108000 km/h.
We know about 400000 species of plants that grow on our planet.
Water occupies about 71% of our planet's surface, 97% of which is salty sea and ocean water.
There are 8000 lightning discharges on Earth in one day.
The longest cave system on Earth is located in the USA, is called Mammoth Cave and is 643 km long.
About 70% of the Earth's oxygen comes from marine phytoplankton, which live mainly in the oceans.
The highest human-recorded temperature on Earth was 56.7 degrees Celsius and was recorded in 1913 in Death Valley, California, USA.
The lowest human-recorded temperature on Earth was -89.2 degrees Celsius and was recorded in 1983 at the Vostok research station in Antarctica.
The noisiest natural place on Earth is the Halema'uma'u crater of the Kilauea volcano in Hawaii, where noise levels exceed 100 decibels.
The quietest natural place on Earth is the Basin of Silence in Hoh Rainforest National Park in Washington State, USA. The noise level there is well below 20 decibels.
The Earth is not a perfect sphere: it is shaped like an oblate ellipsoid, which means that it is slightly flattened at the poles and slightly elongated at the equator.
If the Earth were to suddenly turn into a black hole, the black hole would be the size of a pin head.