Related papers: Whither Does the Sun Rove?
Second part of a didactic sequence of activities on some topics of Astronomy, related mainly with the real shape of the Earth, the gravitational interactions between our planet and other celestial bodies, and the resulting movement of the…
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…
Context. The relation between solar surface rotation and sunspot activity still remains open. Sunspot activity has dramatically reduced in solar cycle 24 and several solar activity indices and flux measurements experienced unprecedentedly…
Tilt angles of close to 30,600 sunspots are determined using Mount Wilson daily averaged magnetograms taken from 1974 to 2012, and MDI/SoHO magnetograms taken from 1996 to 2010. Within a cycle, more than 90% of sunspots have a normal…
Using the convolution of seeing and diffraction, the relation between seeing and aperture in the visibility of sunspots is explored. It is shown that even telescopes with apertures smaller than 5 centimetres are significantly affected by…
We study the visibility of sunspots and its influence on observed values of sunspot region parameters. We use Virtual Observatory tools provided by AstroGrid to analyse a sample of 6862 sunspot regions. By studying the distributions of…
What do we mean by neutrino astronomy? Which information is it able to provide us and which is its potential? To address these questions, we discuss three among the most relevant sources of neutrinos: the Sun; the core collapse supernovae;…
Why does the Sun have a radius around 696000~km? We will see in this article that dimensional arguments can be used to understand the size of the Sun and of a few other things along the way. These arguments are not new and can be found…
The gravitational field of the sun will focus light from a distant source to a focal point at a minimal distance of 550 Astronomical Units from the sun. A proposed mission to this gravitational focus could use the sun as a very large lens,…
Early observations of sunspot were realised by the naked eye. Possible utilization of these records for studying the long-term change in the Sun is discussed here. Other historical sunspot observations with camera obscuras are also…
The solar neutrino anomaly, measurements discrepant from predictions of the Standard Solar Model, has existed for over 30 years. Multiple experiments measuring fluxes from several reactions in the hydrogen fusion chain have added to the…
The Sun shrinks during solar maximum and regrows during solar minimum by a few kilometers. Here, we observe, for the first time, that the solar radius variation shows planetary relationship. This suggests that some remote planetary links…
Solar activity is controlled by the magnetic field, which also causes the variability of the solar irradiance that in turn is thought to influence the climate on Earth. The magnetic field manifests itself in the form of structures of…
At every points of a static equilibrium system, the net force is zero. If one of the composite forces of this system is disappeared, it is no more in equilibrium and this effect of absence spreads through the system with a finite velocity.…
Attitude sensors determine the spacecraft attitude through the sensing of an astronomical object, field or other phenomena. The Sun and fixed stars are the two primary astronomical sensing objects. Attitude sensors are critical components…
Ejections from the Sun can be observed with a higher resolution than in any other astrophysical object: can we build up on solar results and apply them to astrophysical objects? Aim of this work is to establish whether there is any analogy…
The rotation of sunspots of 2 yr in two different solar cycles is studied with the data from the Helioseismic and Magnetic Imager on board the \it Solar Dynamics Observatory \rm and the Michelson Doppler Imager instrument on board the \it…
Bipolar active regions in both hemispheres tend to be tilted with respect to the East West equator of the Sun in accordance with Joys law that describes the average tilt angle as a function of latitude. Mt. Wilson observatory data from 1917…
Assuming that MSW neutrino oscillations occur and ignoring all solar physics except for the constraint that nuclear fusion produces the solar luminosity, we show that new solar neutrino experiments are required to rule out empirically the…
Helioseismology shows that the regions occupied by convection and differential rotation inside the sun almost coincide. This supports the leading theoretical concept for the origin of differential rotation as a result of interaction between…