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Worlds in Collision

12 October 2013

A new explanation for the current rotational state of the planet Mercury has been offered – see http://phys.org/print300689491.html. The rotation is two thirds of the orbital one. It has an elongated orbit around the Sun. The study suggests the 3.2 spin orbit resonance is likely to occur in exoplanetary systems which use tighter formations than our solar system.

At http://phys.org/print300698685.html … it is reasoned that planet Mars is host to the remains of an ancient collision they created many of its asteroids. An astronomer at Armagh Observatory was involved – Apostolous Christou. The asteroids are in resonant orbit with Mars. They trail the planet at its L5 Lagrange point (see figure 1 and 2) and all but one of six of them group up with Eureka, discovered in 1990 (the most ell known of the asteroids, which were found later). Christou suggests the Trojan asteroids were a much bigger space rock at one time. The paper is published in Icarus (May, 2013) but a series of collisions kept breaking them up into smaller fragments. The largest of them, Eureka, is the result of the latest collision – which is why the smaller asteroids are still in tow.

Christou is also dubious about Bruce Willis style asteroid deflections as an explosion might tear them apart into what he calls a cluster bomb of asteroid fragments – which might still target the earth.

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