Related papers: Build your own analemma
The Earth itself is not stationary but keeps revolving, and its motion further satisfies the law of equal area according to the heliocentric doctrine. That satisfaction can be used to construct the mathematical relationships between the…
The study of the global structure of the large-scale magnetic field of the Sun is extremely important for creating a theoretical model of the dynamics of the Sun and predictions of the real situation in the helio- and geomagnetosphere. The…
A surprisingly large amount of information on our solar system can be gained from simple measurements of the apparent angular diameters of the sun and the moon. This information includes the average density of the sun, the distance between…
The parallel globe is an old, very simple and ingenious device that, when systematically employed in astronomy classes, becomes a teaching tool with great potential. Properly oriented according to the local meridian, this instrument allows…
Earth rotation is one of astronomical phenomena without which it is impossible to think of human life. That is why the investigation on the Earth rotation is very important and it has a long history of study. Invention of quartz clocks in…
The classical method for measure the Earth-Sun distance is due to Aristarchus and it is based upon the measure of the angle Moon-Earth-Sun when the Moon is exactly in quadrature. Such an angle is only 9 arcminutes smaller than 90 degrees,…
The Atacama Large Millimeter/submillimeter Array (ALMA) is a new powerful tool for observing the Sun at high spatial, temporal, and spectral resolution. These capabilities can address a broad range of fundamental scientific questions in…
Solar astrometry deals with the accurate measumerent of the solar diameter, and in general with the measurement of the shape of the Sun. During the last decades several techniques have been developed to monitor the radius and the irradiance…
In this paper we describe a simple conceptual problem, regarding the actual position of the Sun at sunset or sunrise. Although this problem can be easily explained in terms of rotating frames of references and standard Coriolis Effect, it…
Variations of the azimuthal magnetic fields of the Sun in the 23-25 activity cycles of the activity cycles are considered. To identify azimuthal magnetic fields, the analysis of daily observations of LOS magnetic fields from the regions…
The attraction of the Moon on objects at the surface of the Earth gives rise to a so-called tidal force which is of the order of 1/10,000,000 times the gravitational force of the Earth. For instance, when the Moon is located between the…
Recent overwhelming evidences show that the sun strongly influences the Earth's climate and environment. Moreover existence of life on this Earth mainly depends upon the sun's energy. Hence, understanding of physics of the sun, especially…
The physical origin of the leap second is discussed in terms of the new gravity model. The calculated time shift of the earth rotation around the sun for one year amounts to $\displaystyle{\Delta T \simeq 0.621 s/ year}$. According to the…
In these notes, we do the computation of the formula giving the expression of solar energy received by an horizontal section of 1 square meter, relatively to the latitude, obliquity and current day (the quantity is also proportional to the…
The Sun's internal structure and dynamics can be studied with helioseismology, which uses the Sun's natural acoustic oscillations to build up a profile of the solar interior. We discuss how solar acoustic oscillations are affected by the…
The equation of time is fundamental for calculating the rising and setting times of the Sun. The concepts of sidereal and solar day and locak noon, we show how the length of the day depends on solar declination and Earth's orbit position,…
The six-degree obliquity of the sun suggests that either an asymmetry was present in the solar system's formation environment, or an external torque has misaligned the angular momentum vectors of the sun and the planets. However, the exact…
ALMA will open a new chapter in the study of the Sun by providing a leap in spatial resolution and sensitivity compared to currently available mm wave- length observations. In preparation of ALMA, we have carried out a large number of…
ALMA provides the necessary spatial, temporal and spectral resolution to explore central questions in contemporary solar physics with potentially far-reaching implications for stellar atmospheres and plasma physics. It can uniquely…
The paper is based on lectures on the internal structure and evolution of the Sun. It contains an outline of observational and theoretical elements of the Standard Solar Model, emphasizing also recent research results on solar rotation,…