A evidência a favor e contra impactos astronômicos sobre a mudança climática e extinções em massa

quarta-feira, junho 24, 2009

The evidence for and against astronomical impacts on climate change and mass extinctions: A review

Authors: C.A.L. Bailer-Jones (Max Planck Institute for Astronomy, Heidelberg)
(Submitted on 24 May 2009 (v1), last revised 23 Jun 2009 (this version, v2))


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 perturbation of the Oort cloud), cosmic rays and supernovae, the effects of which are modulated by the passage of the Sun through the Galactic midplane or spiral arms. Supposed periodicities in the fossil record, impact cratering dates or climate proxies over the Phanerozoic (past 545 Myr) are frequently cited as evidence in support of these hypotheses. This remains a controversial subject, with many refutations and replies having been published. Here I review both the mechanisms and the evidence for and against the relevance of astronomical phenomena to climate change and evolution. This necessarily includes a critical assessment of time series analysis techniques and hypothesis testing. Some of the studies have suffered from flaws in methodology, in particular drawing incorrect conclusions based on ruling out a null hypothesis. I conclude that there is little evidence for intrinsic periodicities in biodiversity, impact cratering or climate on timescales of tens to hundreds of Myr. Furthermore, Galactic midplane and spiral arm crossings seem to have little or no impact on biological or climate variation above background level. (truncated)

Comments: 51 pages, 7 figures, 140 references. To appear in the International Journal of Astrobiology. For hyperref version with full resolution figures see this http URL

Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Galaxy Astrophysics (astro-ph.GA); Populations and Evolution (q-bio.PE)

Cite as: arXiv:0905.3919v2 [astro-ph.EP]

Submission history

From: Coryn Bailer-Jones [view email]
[v1] Sun, 24 May 2009 20:21:24 GMT (404kb,D)
[v2] Tue, 23 Jun 2009 11:54:46 GMT (405kb,D)


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