Terrestrial mass extinctions, cometary impacts and the Sun's motion perpendicular to the galactic plane

  title={Terrestrial mass extinctions, cometary impacts and the Sun's motion perpendicular to the galactic plane},
  author={Michael R. Rampino and Richard B. Stothers},
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 marine mass extinctions during at least the past 250 Myr is 30 ± 1 Myr, with the standard deviation of an individual episode being ±9 Myr. We find this terrestrial cycle to be strongly correlated with the time needed for the Solar System to oscillate vertically about the plane of the Galaxy, which… 

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,

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).

The Galactic Theory of Mass Extinctions: an Update

Astronomical and geological evidence is consistent with the hypothesis that mass extinctions of life on Earth are related to impacts of comets whose flux is partly modulated by the dynamics of the

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

Orbital stability of the unseen solar companion linked to periodic extinction events

Recent suggestions of astronomical causes for the closely periodic extinction events in the geological record1 and the possible periodicities in the cratering record2 have involved two basic ideas.

How stable is an astronomical clock that can trigger mass extinctions on Earth?

  • P. Hut
  • Physics, Geology
  • 1984
The periodicity in mass extinctions observed in the fossil record1,2 may be driven by an astronomical clock consisting of a companion star to the Sun3,4. Each perihelion passage of the companion star

The Sun's motion perpendicular to the galactic plane

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

Cosmic-ray volleys from the galactic center and their recent impact on the earth environment

It is proposed that outbursts of cosmic ray electrons from the Galactic Center penetrate the Galaxy relatively undamped and are able to have a major impact on the Solar System through their ability


. The hypothesis relating mass extinctions of life on Earth to impacts of comets whose flux is partly modulated by the dynamics of the Milky Way Galaxy contains a number of postulates that can be

Cometary Impacts on the Biosphere

There is now a wealth of evidence to link impacts by comets and asteroids with catastrophic disruptions of the biosphere and mass extinctions. Such evidence includes impact craters formed close to



Consequences of a past encounter of the earth with an interstellar cloud

In its motion through the galaxy the sun may have suffered a number of encounters with dense interstellar clouds for which the number density of molecular hydrogen H2 is > 10³ cm−3. Several authors

Frequency of nearby supernovae and climatic and biological catastrophes

MCCREA1,2 has proposed that the encounter of the Solar System with a dense cloud of interstellar material during its passage through a spiral arm of the Galaxy may produce such climatic catastrophes

The effect of interstellar matter on climatic variation

The effect of interstellar matter on the sun's radiation is considered with a view to explaining changes in terrestrial climate. It appears that a star in passing through a nebulous cloud will

Extraterrestrial Cause for the Cretaceous-Tertiary Extinction

A hypothesis is suggested which accounts for the extinctions and the iridium observations, and the chemical composition of the boundary clay, which is thought to come from the stratospheric dust, is markedly different from that of clay mixed with the Cretaceous and Tertiary limestones, which are chemically similar to each other.

Is the solar system entering a nearby interstellar cloud

A model, based on different observations of the local interstellar medium, indicates the presence of a very close interstellar cloud in front of the Scorpius-Ophiuchus association (almost in the

Comet showers and the steady-state infall of comets from the Oort cloud

The appearance of an inner edge to the Oort comet cloud at a semimajor axis of a = (1--2) x 10/sup 4/ AU is an observational artifact. Stellar perturbations are frequent enough and strong enough to


OLIN J. EGGEN Mount Stromlo and Siding Spring Observatories Received July 8, 1969 The extensive hotometric and nsdial velocity material for A-type stars near the NGP, collecte by Peri , is discnssed

Climatic effects during passage of the Solar System through interstellar clouds

IT seems likely that the Solar System passes through regions where there are a large number of dense interstellar clouds as the compression zone of the galactic spiral density wave passes the Sun.

Review Lecture - Long time-scale fluctuations in the evolution of the Earth

  • W. Mccrea
  • Physics, Geology
    Proceedings of the Royal Society of London. A. Mathematical and Physical Sciences
  • 1981
This lecture is an attempt to review current knowledge about certain terrestrial phenomena with the twofold purpose: (a) to discover the extent to which the behaviour of the Earth may be influenced