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Question
Why is iridium more common in space objects than on earth?
Hello,
Actually, the *conjecture* that iridium (Ir) is more common in space objects (e.g. asteroids) was proposed as part of a *hypothesis* advanced to account for the extinction of the dinosaurs, in the KT-event of 65 million years ago.
That KT event was identified by Alvarez and co-workers from a thin stratum of Ir-rich clay between the Cretaceous and Tertiary eras of geologic time. Though their hypothesis has wide support in the astronomical community, there have since been other (geological) hypotheses advanced that do not depend on an anomalous abundance of Ir in cosmic objects.
For example, geologist Dewey M. McClean and others argue that the iridium in the clay layer could equally have been of volcanic origin, from here on Earth - since the Earth's core is actually rich in Ir.
Thus, it is an incorrect assumption to think or believe iridium is only peculiar to or vastly more abundant in space objects.
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Answers by Expert:
Philip Stahl
Expertise
I have forty years of experience in Astronomy, specifically solar and space physics. My specialties include the physics of solar flares, sunspots, including their effects on Earth and statistics as applied to astronomical investigations.
Experience
Astronomy: more than forty years experience starting with construction of my own simple telescopes. Worked at university observatory in college, doing astrographic measurements. M.Phil. degree in Physics/Solar Physics and more than ten years as researcher.
Organizations
American Astronomical Society (Solar Physics and Dynamical Astronomy divisions), American Mathematical Society, American Geophysical Union
Publications
Solar Physics (journal), The Journal of the Royal Astronomical Society of Canada, The Proceedings of the Meudon Solar Flare Workshop (1986), The Proceedings of the Caribbean Physics Conference (1985). Books: 'Selected Analyses in Solar Flare Plasma Dynamics', 'Physics Notes for Advanced Level'.
Education/Credentials
B.A. Astronomy, M. Phil. Physics
Awards and Honors
American Astronomical Society Studentship Award (1984), Barbados Government Award for Solar Research
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