Johannes Kepler has established three postulates, popularly known as Kepler's laws, which are linked to the movement made by each planet in its orbit around the sun.
There are three Kepler laws and they pay tribute in their name to a German mathematician and astronomer named Johannes Kepler . He, many years ago (between 1609 and 1619), was in charge of formulating the statements that allow us to establish the movements that the planets make in their orbits around the sun.
These contents are valuable because, for example, they help to anticipate how a celestial body may behave orbiting larger bodies. In addition, they were very useful to Isaac Newton when developing the law of universal gravitation .
It should be noted that the surname of the aforementioned scientist (who had the opportunity to grow professionally and deepen his research thanks to the fact that his colleague of Danish origin Tycho Brahe had him as an assistant and disciple) was also immortalized in a star . As documented, in 1604 Johannes offered a detailed report on the observation of SN 1604 , a supernova that appeared in the Milky Way and, for more than a year, could be seen with the naked eye. Kepler , a famous, admired and respected reference in Astronomy who accumulated data on Saturn , Venus , Mars , Jupiter , Mercury and Earth , even designed a refracting telescope.
What are Kepler's laws?
In order to understand the significance of Kepler's so-called laws, we must begin to approach these guidelines by learning about what they are and what they are like.
Thus, it is appropriate to point out that the first of these laws emphasizes the elliptical orbit drawn by each planet that moves around the sun, which is located at a focus of the ellipse .
Kepler's law , ranked second, says that the areas traveled by the radius vector that, in equal times, connect a planet and the sun are identical. It is interesting to note that the area postulate is equivalent to constancy linked to angular momentum . And in this context it is important to know that aphelion is identified as the point that is furthest from the orbit of a certain planet around the sun), while the perihelion is that which is closest to the orbit drawn by a celestial body in the surroundings of the sun.
The last of Kepler's laws , known as the law of periods , states that the square corresponding to the orbital period of any planet analyzed maintains a direct proportionality with the cube of the length of the semimajor axis of the elliptical orbit it traces.
Perihelion is identified as the point in the orbit of a certain celestial body that is closest to the sun, while aphelion is the point that is furthest from the orbit of each planet around the sun.
Applications and implications
Kepler's laws do not lose validity and have multiple scopes and applications. With them, for example, it is possible to establish the trajectory , as well as the period and orbital speed, of comets, natural satellites (such as the moon), planets and asteroids.
With Johannes ' legacy as inspiration, the Kepler mission was given impetus in 2009 . The operation, which involved the launch of a space observatory orbiting the sun, was part of a NASA program called Discovery . From the data that could be obtained thanks to the Kepler space telescope , it was established that in our galaxy there is a greater abundance of planets than stars and revolutionary findings were achieved regarding the variety of existing exoplanets . It is also interesting to note that there are several extrasolar planets that honor the German scientist from their name, such as Kepler-186b , Kepler-186c , Kepler-186d , Kepler-186e and Kepler-186f .
Kepler, who used astronomical observations carried out by Tycho Brahe for his studies, focused his attention on planetary movement based on the idea that the sun, in a certain way, was the true heart or center of the solar system.
Allusions to Kepler's laws
Since they came to light, Kepler's laws have been cited in a large number of scientific texts, research papers, journalistic articles, etc.
But it was Johannes himself who contributed to making them popular from the first moment by transforming them into part of the content of "Astronomia nova" , a book that, in 1609 , was launched in Prague . In this ancient work that is structured in five parts, the author alludes to Kepler's first two laws , focuses on the apparent movement of the planet Mars and raises a discussion that involves both the geocentric model and the heliocentric model , for example.
Nor can we fail to remember that, in 1619 , this same scientist included the initial formulation of the third law associated with planetary motion in a publication entitled "Harmonices mundi" . In the latter case, Kepler made an attempt to explain each planetary movement, finding as a useful and original resource a geometric model based on proportions between different polyhedra, which he related to musical scales. In this scenario, the expert tried positioning the orbits of different planets within Platonic solids or perfect polyhedra. Furthermore, he was encouraged to postulate that each of the planets could produce, throughout their movement around the sun, a certain musical tone, the frequency of which could vary depending on the angular velocity of these planets calculated in comparison to the sun.