rocky planets, also known as telluric, terrestrial or solid, are stars of Solar system that do not have their own light and orbit around the Sun, the main star of this system. They are called "rocky" because they are mainly formed by rocksand metals.
The rocky planets are:
Mercury
Venus
Earth
Mars
Lookalso:Gaseous Planets - Discover this other group of planets
Origin
The rocky planets formed about 4.6 billion years. There is still no entirely satisfactory theory to explain this formation, as well as that of the entire Solar System. Currently, the most accepted theory is the solar nebula theory, also known as the early solar nebula theory. This theory was first proposed in 1644, by Rene Descartes, and reformulated in 1796, by Pierre-Simon de Laplace.
The solar nebula would be a a cloudinterstellar which, when rotating at high speed, would have contracted and entered into collapse. Gravity caused the concentration of matter in the cloud, after the collapse, to give rise to the Sun.
At particlesremnants of the collapse of the cloud that were more external to the central part gave rise to the planetsgaseous. already the particles that stayed more near the central part formed the planetsrocky. This was because lower density materials tend to move away from the Sun, while heavier materials are concentrated closer to the star. Planets are therefore considered “by-products” of the formation of the Sun.
Read too:Main harmful effects of the sun
Characteristics of rocky planets
See below the main characteristics of the rocky planets:
→ Mercury
Among the planets in the Solar System, Mercury is the closer to the Sun. The star is approximately 57,910,000 km from the star (Neptune, the last planet in the Solar System, is 4,504,300,000 km from the Sun). O core of Mercury consists of iron. Your atmosphere is composed mostly of helium. The planet has no satellites.
→ Venus
Venus is located approximately 108,200,000 km from the Sun. It is one of the brightest stars in the sky, being also known as Dalva star. The planet has significant similarities to Earth, including its mass. THE temperature of the planet can reach 400°C, making the existence of water in the liquid state impossible.
THE atmosphere of Venus is made up of over 96% of dioxideof carbon and about 4% per nitrogen. Carbon dioxide has the ability to absorb the sun's rays, preventing all the heat that reaches the surface from returning to space. Therefore, carbon dioxide ends up trapping heat in the atmosphere, configuring what we know as greenhouse effect. Thus, the large amount of this gas causes the greenhouse effect on the planet to be aggravated, thus being one of the factors that cause high temperatures. The planet has no satellites.
See more:Sputnik, Earth's first artificial satellite
→ Earth
THE Earth, the planet we inhabit, presents conditions favorable to the existence of life, such as Water present in its three physical states (liquid, gas and solid), as well as the presence of dioxideincarbon (about 0.035%), which contributes to the It is madestove happen, keeping the temperatureaverage of the Earth around 14°C and avoiding a huge thermal amplitude (difference between the maximum temperature and the minimum temperature).
THE planet atmosphere is composed not only of carbon dioxide, but also of nitrogen,oxygen and steamof water. The Earth has a satelliteNatural, The Moon, whose rotation is synchronized with that of the planet. THE Earth's internal structure it is divided into three layers: earth's crust, mantle and core.
Read more:Earth atmosphere - know its importance and characteristics
→ Mars
Known as PlanetRed due to its coloration, given by the presence of a soil rich in iron and silicon, Mars is the third planet in relation to the Sun, being approximately 227,940,000 km away from this star.
THE mars atmosphere it consists of gases such as nitrogen, carbon dioxide, traces of oxygen and carbon monoxide and water vapor. Throughout the day, the temperature on the planet varies between -76°C and -10°C, and may increase to a maximum of 5°C due to the presence of gases such as carbon dioxide. There are signs of the existence of Watercold underground. Mars has two natural satellites.
Also know: What are the planets in the Solar System?
Fun facts about rocky planets
1) What is the biggest rocky planet?
The largest rocky planet in the Solar System is the planet we inhabit, Earth. The planet's mass was estimated by British scientist Henry Cavendish. The scientist concluded through studies that the Earth has a mass of approximately six million billion kilograms.
2) What is the smallest rocky planet?
Mercury is the smallest planet in the Solar System, with a mass of approximately 3.303x1023kg.
3) How big is the sun?
The Sun has a diameter of approximately 1.39 million kilometers (109 times larger than the Earth's) and its mass is about 332,900 times that of our planet.
4) Is there a rocky planet outside the Solar System?
In 2014, astronomers at the University of Geneva discovered the existence of a planet made up of rocks whose mass is 17 times that of Earth. This planet is outside the Solar System and was called Kepler-10c. This newly discovered planet is approximately 568 light-years away from Earth.
Differences between rocky planets and gaseous planets
rocky planets |
gas planets |
Mercury, Venus, Earth and Mars |
Jupiter, Saturn, Uranus, Neptune |
Mass: small |
Mass: large |
Density: large. |
Density: small. |
Formed by rocks and heavy metals such as silicates and iron. |
Formed by gases such as hydrogen, helium and carbon dioxide. |
Number of satellites: few or none. |
Number of satellites: several. |
Solar system
The Solar System corresponds to the set of stars that are located in the Milky Way. Formed not only by the Sun and the planets, the Solar System also has other celestial bodies, such as comets, asteroids, meteoroids, dwarf planets, among others.
O Sun is the main starl of this system and, around it, the planets orbit. This star has a diameter of approximately 1.39 million kilometers and is formed, mostly, by hydrogen and helium. In order of distance from the Sun, the planets are organized as follows:
Sun → Mercury → Venus → Earth → Mars → Jupiter → Saturn → Uranus → Neptune |
In 2006, the International Astronomical Union (WOW), which regulates classifications, nomenclatures and definitions in Astronomy, announced that Pluto (until then considered a planet in the Solar System) is no longer a planet, being "downgraded" to the category of dwarf planet. This change occurred due to discoveries made in recent years that found the existence of celestial bodies with characteristics similar to those of Pluto.
This situation created a problem: either it will be necessary for each discovery to increase the number of planets in the Solar System or to create a new nomenclature for the discovered celestial bodies. And so did the UAI. In addition to Pluto, the Solar System also has other dwarf planets: Ceres, Eris, Haumea and Makemake. To learn more about the subject, read: Solar system.
