For more than 4 billion years, the Earth has been impacted by small asteroidal and cometary bodies. These objects are often thought of as debris from solar system formation and their effect on the Earth, the Moon and other planets has been significant. We only need to look at the surface of the Moon to appreciate the influence that impacts have made on its landscape. While very large impacts are now so infrequent that they can be ignored, even small objects can pose a threat. The hypothesis for the extinction of the non-avian dinosaurs as a result of an asteroidal impact remains plausible although disputed. Even more recent impact sites can be found on Earth – Nordlinger Ries Crater in southern Germany and Barringer Crater in Arizona are the two best known examples.
For the first time in history, however, we are close to having the technology and capability of defending ourselves against future asteroidal or cometary impactors. In this quarter’s Observer you can read about the DART mission which successfully impacted a small asteroidal object in an attempt to deflect its path. For the future, the recently adopted Comet Interceptor mission will park and wait for an, as yet unknown, comet, steer towards it, and complete a fly-by – a possible pre-cursor mission to a similar demonstration of deflection.
While the space defence aspects of these missions is strongly emphasized, the scientific knowledge acquired of the targets is also hugely valuable in determining their importance and roles in the evolution of our solar system. Science can be found in everything we do.
With my best regards,
Nicolas ThomasCategories: External Newsletter
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