Related papers: L'Equazione del Tempo
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…
Solar oscillations frequencies show a distinct change with solar activity. The changes in frequencies can be used to study the time variation of solar structure. We discuss constraints on the changes in solar structure with time as obtained…
The Sun provides the energy required to sustain life on Earth and drive our planet's atmospheric circulation. However, establishing a solid physical connection between solar and tropospheric variability has posed a considerable challenge…
We analyze the long-term tidal evolution of a single-planet system through the use of numerical simulations and averaged equations giving the variations of semi-major axis and eccentricity of the relative orbit. For different types of…
The chemical composition of the Sun is among the most important quantities in astrophysics. Solar abundances are needed for modelling stellar atmospheres, stellar structure and evolution, population synthesis, and galaxies as a whole. The…
Variation in total solar irradiance is thought to have little effect on the Earth's surface temperature because of the thermal time constant--the characteristic response time of the Earth's global surface temperature to changes in forcing.…
Confusion and disagreement around the notion of time is due to the fact that we often fail to recognize that we call 'time' a variety of distinct notions, only partially related to one another. Many apparently obvious properties of time are…
Basic for the definition of 'time' are clocks operating under stationary conditions. The periods of two clocks can be compared with each other via two return experiments. The central clock mediates between the rotating and the inertial…
Time plays a fundamental role in our ability to make sense of the physical laws in the world around us. The nature of time has puzzled people -- from the ancient Greeks to the present day -- resulting in a long running debate between…
This paper describes some of the astronomical effects that could be important for understanding the ice ages, historic climate changes and the recent temperature increase. These include changes in the sun's luminosity, periodic changes in…
Luminosity, which is the total amount of radiant energy emitted by an object, is one of the most critical quantities in astrophysics for characterizing stars. Equally important is the temporal evolution of a star's luminosity because of its…
The dynamic activity of the Sun -- sustained by a magnetohydrodynamic dynamo mechanism working in its interior -- modulates the electromagnetic, particulate and radiative environment in space. While solar activity variations on short…
Regular spaceborne measurements have revealed that solar brightness varies on multiple timescales, variations on timescales greater than a day being attributed to surface magnetic field. Independently, ground-based and spaceborne…
A method to measure the seeing from video made during drift-scan solar transits is proposed. The limb of the Sun is projected over a regular grid evenly spaced. The temporal dispersion of the time intervals among the contacts between solar…
Solar neutrino physics is an exciting and difficult field of research for physicists, where astrophysics, elementary particle and nuclear physics meet. \ The Sun produces the energy that life has been using on Earth for many years, about…
In this monograph (written in 1973-1974) the author uses the theory of mechanics of the inertless mass to investigate the structure of heavenly bodies of the solar system. The structure of the Sun and planets is the sole reason of the…
The solar luminosity in the visible changes at the 10-3 level, following an 11 years period. In X-rays, which should not be there, the amplitude varies 100000 times stronger, making their mysterious origin since the discovery in 1938 even…
A fundamental description of time can be consistent not only with the usual monotonic behavior but also with a periodic physical clock variable, coupled to the degrees of freedom of a system evolving in time. Generically, one would in fact…
A careful study is made of the operational meaning of the time symbols appearing in the space-time Lorentz transformation. Four distinct symbols, with different physical meanings, are needed to describe reciprocal measurements involving…
We present a simple, free, fast and accurate C/C++ and Python routine called SolTrack, which can compute the position of the Sun at any instant and any location on Earth. The code allows tracking of the Sun using a low-specs embedded…