Related papers: Testing the link between terrestrial climate chang…
We use the most up to date Milky Way model and solar orbit data in order to test the hypothesis that the Sun's galactic spiral arm crossings cause mass extinction events on Earth. To do this, we created a new model of the Milky Way's spiral…
We present a calculation of the Sun's motion through the Milky Way Galaxy over the last 500 million years. The integration is based upon estimates of the Sun's current position and speed from measurements with Hipparcos and upon a realistic…
The short term variability of the Galactic cosmic ray flux (CRF) reaching Earth has been previously associated with variations in the global low altitude cloud cover. This CRF variability arises from changes in the solar wind strength.…
Numerous studies over the past 30 years have suggested there is a causal connection between the motion of the Sun through the Galaxy and terrestrial mass extinctions or climate change. Proposed mechanisms include comet impacts (via…
Variations in the flux of Galactic Cosmic Rays (GCR) at Earth during the last 4.6 billion years are constructed from information about the Star Formation Rate (SFR) in the Milky Way and the evolution of solar activity. The variations of GCR…
Recent knowledge of Galactic dynamics suggests that stars radially move on the disk when they encounter transient spiral arms that are naturally generated during the process of disk formation. We argue that a large movement of the solar…
A brief review is given of different methods used to determine the pattern speeds of the Galactic bar and spiral arms. The Galactic bar rotates rapidly, with corotation about halfway between the Galactic center and the Sun, and outer…
A striking coincidence of revolution periods of S-stars orbiting a supermassive black hole at the Galactic Center of the Milky Way and oscillation periods of such solar and terrestrial observables as the sunspot number, the geomagnetic…
Reconstructions of the paleoclimate indicate that ancient climatic fluctuations on Earth are often correlated with variations in its orbital elements. However, the chaos inherent in the solar system's orbital evolution prevents numerical…
We construct a Galactic cosmic ray (CR) diffusion model while considering that CR sources reside predominantly in the Galactic spiral arms. We find that the CR flux (CRF) reaching the solar system should periodically increase each crossing…
We compare the observed radial velocity of different arm tracers, taken near the tangent to a spiral arm. A slight difference is predicted by the density wave theory, given the shock predicted at the entrance to the inner spiral arm. In…
The Sun's outer atmosphere is heated to temperatures of millions of degrees, and solar plasma flows out into interplanetary space at supersonic speeds. This paper reviews our current understanding of these interrelated problems: coronal…
Spiral density wave theory attempts to describe the spiral pattern in spiral galaxies in terms of a long-lived wave structure with a constant pattern speed in order to avoid the winding dilemma. The pattern is consequently a rigidly…
We revisit the question of whether the observed periodicity of comet impacts on Earth is consistent with Solar oscillation about the Galactic midplane and spiral arm crossings, here in the context of dissipative dark matter models. Consider…
The astronomical theory of Milankovitch relates the changes of Earth' past climate to variations in insolation caused by oscillations of the orbital parameters. However, this theory has problems to account for some major observed phenomena…
Most transiting planets orbit very close to their parent star, causing strong tidal forces between the two bodies. Tidal interaction can modify the dynamics of the system through orbital alignment, circularisation, synchronisation, and…
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…
This thesis assesses the influence of astronomical phenomena on the Earth's biosphere and climate. I examine in particular the relevance of both the path of the Sun through the Galaxy and the evolution of the Earth's orbital parameters in…
The Galactic cosmic ray (GCR) intensity has been postulated by others to vary cyclically with a peak to valley ratio of ~3:1, as the Solar System moves from the Spiral Arm to the Inter-Arm regions of the Galaxy. These intensities have been…
The recent detections of temperate terrestrial planets orbiting nearby stars and the promise of characterizing their atmospheres motivates a need to understand how the diversity of possible planetary parameters affects the climate of…