The extinction 65 million years ago is indicated with the little dinosaur icon. The peak near 11 Ma is real, but exaggerated by the requirement that the plot go to zero at the present.
Arrows are plotted every 26 million years. Note that many of these are close to the peaks in the extinction rate. This is the apparent 26 million year periodicity discovered by Raup and Sepkoski.
There have been many statistical studies of these data. Although several studies indicate the periodicity is significant, not everyone agrees. I suggest that you decide for yourself. If you decide that the extinctions are not statistically significant, then there is no need for the Nemesis theory. Additional work by Sepkoski shows that the periodicity is also present for fossil genera. His results were published in the Journal of the Geological Society of London, vol , pp Figure 2 from this paper is shown below.http://st-bernhard-wol.de/modules/2019-06-15/2112-blauer-haken-whatsapp.php
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Please note that the time axis has been reversed compared to that of the previous figure. The upper time series labeled Total is for Sepkoski's entire data set of 17, genera, whereas the lower "filtered" time series is for a subset of 11, from which genera confined to single stratigraphic intervals have been excluded.
The vertical lines are plotted at 26 Myr intervals. The Nemesis theory was devised to account for this regularity in the timing of the mass extinctions reported by Raup and Sepkoski.
According to this model, a companion star orbiting the Sun perturbs the Oort comet cloud every 26 Myr causing comet showers in the inner solar system. One or more of these comets strike the Earth causing a mass extinction. The Nemesis theory was originally published in Nature by Davis, Hut, and Muller vol , pp , You can read Chapter 1 Cosmic Terrorist. This book is out of print, but I have some extra copies.
There is a great deal of confusion among astronomers about the stability of the Nemesis orbit. Even many theorists who should know better believe that the orbit is unstable, and that the original Nemesis paper was in error. However detailed calculations by Piet Hut at the Institute for Advanced Study in Princeton show that the original estimate about the orbit were correct.
Hut's results were published in Nature, vol , pp.
In our original paper we had stated that the orbit presently has a stability time constant of approximately one billion years. Many people naively assumed that this was incompatible with the 4. But unlike the lifetime of a radioactive element, the lifetime of the Nemesis orbit is not predicted to be constant with time.
He bade Venus Aphrodite , in the form of an eagle, pursue him; he, changed to a swan as if in flight from the eagle, took refuge with Nemesis and lighted in her lap. Nemesis did not thrust him away, but holding him in her arms, fell into a deep sleep. While she slept, Jupiter [Zeus] embraced her and then flew away. Because he was seen by men flying high in the sky, they said he was put in the stars. To make this really true, Jupiter put the swan flying and the eagle pursuing in the sky.
Definition of 'nemesis'
But Nemesis, as if wedded to the tribe of birds, when her months were ended, bore an egg. Mercurius Mercury Hermes took it away and carried it to Sparta and threw it in Leda's lap. From it sprang Helen, who excelled all other girls in beauty. One source of the myth says that Nemesis was the mother of the Telchines , whom others say were children of Pontus and Gaea or Thalassa.
Although a respected goddess, Nemesis brought much sorrow to mortals such as Echo and Narcissus. Narcissus was a very beautiful and arrogant hunter from the territory of Thespiae in Boeotia , who disdained the ones who loved him. Nemesis lured him to a pool where he saw his own reflection in the water and fell in love with it, not realizing it was only an image. He was unable to leave the beauty of his reflection and he eventually died. A festival called Nemeseia by some identified with the Genesia was held at Athens. Its object was to avert the nemesis of the dead, who were supposed to have the power of punishing the living, if their cult had been in any way neglected Sophocles , Electra , ; E.
Nemesis () - IMDb
Rohde , Psyche, , i. At Smyrna there were two manifestations of Nemesis, more akin to Aphrodite than to Artemis. The reason for this duality is hard to explain. It is suggested that they represent two aspects of the goddess, the kindly and the implacable, or the goddesses of the old city and the new city refounded by Alexander.
The martyrology Acts of Pionius , set in the " Decian persecution " of AD —51, mentions a lapsed Smyrnan Christian who was attending to the sacrifices at the altar of the temple of these Nemeses. Nemesis was one of several tutelary deities of the drill-ground as Nemesis campestris. Modern scholarship offers little support for the once-prevalent notion that arena personnel such as gladiators , venatores and bestiarii were personally or professionally dedicated to her cult.
Rather, she seems to have represented a kind of "Imperial Fortuna " who dispensed Imperial retribution on the one hand, and Imperially subsidized gifts on the other; both were functions of the popular gladiatorial Ludi held in Roman arenas. In the third century AD, there is evidence of the belief in an all-powerful Nemesis-Fortuna.
She was worshipped by a society called Hadrian's freedmen. Ammianus Marcellinus includes her in a digression on Justice following his description of the death of Gallus Caesar. From Wikipedia, the free encyclopedia. Goddess of retribution in Greek mythology. For other uses, see Nemesis disambiguation.
Nemesis , by Alfred Rethel Beekes , Etymological Dictionary of Greek , Brill, , pp. This is the ancient morality of the gift, which has become a principle of justice". Hornum observed in Nemesis, the Roman State and the Games , Scott Smith, Stephen Trzaskoma, and Hyginus. Indianapolis: Hackett Pub. Retrieved 21 January Ancient Greek deities by affiliation.
Eos Helios Selene. Asteria Leto Lelantos. Astraeus Pallas Perses. Atlas Epimetheus Menoetius Prometheus. Aoide Arche Melete Mneme. Dike Eirene Eunomia.