The Sun's motion perpendicular to the galactic plane

  title={The Sun's motion perpendicular to the galactic plane},
  author={John N. Bahcall and Safi R. Bahcall},
The period and amplitude of the Sun's motion perpendicular to the galactic plane are important parameters in some explanations of the terrestrial mass extinctions and cratering records1–5. Here we have calculated the range of periods and vertical excursions that are consistent with the distributions of tracer stars in the Galaxy and have also evaluated the probable phase jitter in the solar period. We find acceptable half-periods for the vertical oscillation that range from 26 to 37 Myr… 
Terrestrial record of the Solar System's oscillation about the galactic plane
Impact cratering on the Earth over the past 600 Myr has been partly sporadic, partly episodic. The episodic component is suspected to have been cyclical, with a mean period of ∼32 Myr (refs 1, 2).
Quasi-regular staying of solar system in supernova remnants and natural earth history
Abstract The Solar system, oscillating relative the Galaxy midplane during its revolution around the Galactic center, can occasionally fall inside the gas-dust interstellar clouds, which include
NEOs and Impacts: The Galactic Connection
The orbit of the solar system within the Galaxy is subject both to adiabatic tidal forces and to irregular buffeting caused by encounters with molecular clouds and spiral arms, while the long-period
Galactic tidal perturbations of long-period comets and the distribution of the inclinations
Perturbation of the perihelion distance q of long-period comets by the galactic tidal force is calculated using Cowell's method. It is shown that the maximum perturbation is suffered by those with i
Galactic tides affect the Oort cloud: an observational confirmation
There are 152 known original orbits of comets with a period larger than ten thousand years. Their aphelia are shown here to avoid three zones of the celestial sphere, namely the two galactic polar
Disc dark matter in the Galaxy and potential cycles of extraterrestrial impacts, mass extinctions and geological events
A cycle in the range of 26–30Myr has been reported in mass extinctions, and terrestrial impact cratering may exhibit a similar cycle of 31 ± 5Myr. These cycles have been attributed to the Sun’s
Long-term Variations in the Galactic Environment of the Sun
We review the long-term variations in the galactic environment in the vicinity of the solar system. These include changes in the cosmic ray flux, in the pressure of the different interstellar
Is the Solar System's Galactic Motion Imprinted in the Phanerozoic Climate?
It is proposed that the galactic motion left an imprint on the terrestrial climate record because of the effective average galactic density encountered by the solar system, which suggests the presence of a disk dark matter component.
Rocky planetesimals as the origin of metals in DZ stars
Based on this result, pollution by the interstellar medium cannot simultaneously account for both the polluted and non-polluted subpopulations, and it is probable that these white dwarfs are contaminated by circumstellar matter; the rocky remains of terrestrial planetary systems.
The near-parabolic flux and the origin of short-period comets
The origin of short-period comets, usually believed to arise by planetary perturbations acting on nearly parabolic orbits, has been unclear for many years1. Given the observed near-parabolic flux,


Terrestrial mass extinctions, cometary impacts and the Sun's motion perpendicular to the galactic plane
Episodes of mass extinctions on the Earth are now strongly suspected to be cyclical1. We report here that our analysis of the data of Raup and Sepkoski1 suggests that the dominant cyclicity in major
Cometary impacts, molecular clouds, and the motion of the Sun perpendicular to the galactic plane
Raup and Sepkoski1 have presented evidence from marine fossils for a 26-Myr periodicity in the occurrence of mass extinctions. Using the same data Rampino and Stothers2 obtained a different period,
Periodic mass extinctions and the Sun's oscillation about the galactic plane
Raup and Sepkoski1 have recently reported evidence fora 26-Myr periodicity in the occurrence of mass extinctions based on a study of marine fossils. The data baseline of 250 Myr suggests events of
Self-consistent determinations of the total amount of matter near the sun.
The combined Poisson-Boltzmann equation for the gravitational potential is solved numerically for detailed Galaxy models whose mass components have been determined previously by a variety of
Evidence from crater ages for periodic impacts on the Earth
Recent evidence has indicated that the impact of a comet or asteroid may have been responsible for mass extinction at the ends of both the Cretaceous1 and the Eocene2–4. Quantitative analysis by Raup
The interaction of the spiral density wave and the Sun's galactic orbit
The galactocentric radial motion of the Sun introduces another periodicity to the encounters between the Sun and the spiral density wave. We describe a model simulation of the effect and present the
Models for the Galaxy and the Predicted Star Counts
A detailed model is constructed for the disk and spheroid components of the Galaxy from which the distribution of visible stars and mass in the Galaxy is calculated. The application of star counts to
Periodicity of extinctions in the geologic past.
  • D. Raup, J. Sepkoski
  • Medicine, Biology
    Proceedings of the National Academy of Sciences of the United States of America
  • 1984
The temporal distribution of the major extinctions over the past 250 million years has been investigated statistically using various forms of time series analysis and contains 12 extinction events that show a statistically significant periodicity.