Starting with the fact of the Second Law of Kepler, and using the result of the Orbital Angular Momentum as a constant value in terms so the reduced mass and the eccentricity of the ellipse, the Third Law of Kepler can be shown. The square of the period of a planet is directly proportional toContinue reading “Lesson 10”

# Category Archives: LECTURE

## Lesson 9

Velocities at perihelium and aphelion Using the deduced equation for the position vector in terms of the orbital angular momentum, we may develop equations to calculate the velocities in the perihelium and in the aphelion. errata: a correction must be made in the word “aphelium” and substitute it for the proper expression aphelion. Watch theContinue reading “Lesson 9”

## Lesson 8

Kepler’s Second Law In this 13 minutes video, you will be introduced to the Second of the three laws of Johannes Kepler. This mathematical treatment of the law, makes clear about the changes in velocities at different places in the elliptical trajectory, and explains why the planets are faster at perihelium. Watch the video, byContinue reading “Lesson 8”

## Lesson 7

In this video you will follow up with the Orbital angular momentum-continuation from last lecture. The presentation is made in Spanish. I was taping the presentation in Spanish, and after I realized it was already advanced that I decided to finished it in Spanish language. So, but an English speaking person can follow it also.Continue reading “Lesson 7”

## Lesson 6

The Orbital Angular Momentum The orbital angular momentum is a very important concept that has physical consequences for a body revolving around another, like planets around the stars, or moons around the planets. In this lesson, we are exploring what the orbital angular momentum is, and developing an expression for the one problem body problemContinue reading “Lesson 6”

## Lesson 5

In the literature we find that, to calculate the distance in parsecs (pc) to a particular star, we need to know the parallax angle in seconds of an arc, and determine the reciprocal of it. The question I would like to explore in this lesson is, the why do we do this. Look at theContinue reading “Lesson 5”

## Lesson 4

In Lesson 1 you can follow the definition of the Astronomical Unit based on a “test” particle, that takes to revolve around a major body, exactly one year. We saw, that based on this definition, the Earth’s distance from the Sun is slightly smaller, compare with the test particle’s distance around the Sun. The resultContinue reading “Lesson 4”

## Lesson 3

This lecture can be used as for college level students. To continue with the understanding of Kepler’s laws, the presentation is a build up of the Physical-Mathematical concepts of the 2-Body problem and reduced mass. It culminated with the deduction of the total energy for the reduced mass system. The results will be used inContinue reading “Lesson 3”

## Lesson for Today- Lesson 02

How do Planets, or other objects move around a star? The observations of the German astronomer, Johannes Kepler (27 December 1571 – 15 November 1630), deduced the three laws that are being used today to answer that question. I will describe the three laws in three different lessons, starting today with the first one below.Continue reading “Lesson for Today- Lesson 02”

## Lesson for Today – Lesson 01

The Astronomical Unit – Definition The distance from a particle (or a planet) to the Sun, is measured in terms of the semimajor axis of the ellipse traced by that body around the Sun. According to Kepler’ law, the square of the period (time that the body takes to go once around de Sun inContinue reading “Lesson for Today – Lesson 01”