Physics Talk

https://commons.wikimedia.org/wiki/File:Impact_event.jpg In Part 1 ( phys-talk.blogspot.com/2020/03/planetary-defence-part-1-introduction.html ), I looked at the impacts of asteroids and comets and how to distinguish between them. The first step to protecting our planet from potentially dangerous asteroid and comet attacks is detection. This allows scientists to predict whether an object poses a threat to the Earth through orbit determination. If a hazardous near-earth object is found, the next step is the ‘implementation of measures to deflect or disrupt’ it. [1]   Detection The main method of detecting near-earth objects is through telescope observations. For instance, NASA currently supports ‘several ground-based observatories that scan the skies for asteroids’ (e.g. the Catalina Sky Survey in Arizona) [2] as part of its ‘Near-Earth Observation Program.’ At these observatories, the sky is scanned and images are taken where an asteroid, which reflects...

E. Kolmhofer, H. Raab; Johannes-Kepler-Observatory, Linz, Austria (http://www.sternwarte.at) / CC BY-SA (https://creativecommons.org/licenses/by-sa/3.0) The Chicxulub Crater in Mexico, spanning over 110 miles in width, marks the spot where, 66 million years ago, 'an asteroid the size of a mountain' [1] struck the Earth. The asteroid travelled at a speed of around 40,000 miles per hour [1] before pummelling the planet with an 'explosive yield estimated at 100 trillion tons of TNT.' [1] This is 'two million times stronger than the most powerful man-made bomb’ [2] . The immense impact of the asteroid is believed to have caused mass extinction including that of the dinosaurs.  Although they are rare occurrences, scientists have tried to find ways to protect the planet from asteroid and comet attacks which could potentially have devastating consequences as shown by the dinosaur-ending event 66 million years ago.   Asteroids vs Comets Asteroids are ...

Picture credits: X-ray: NASA/CXC/Naval Research Lab/Giacintucci, S.; XMM:ESA/XMM; Radio: NCRA/TIFR/GMRTN; Infrared: 2MASS/UMass/IPAC-Caltech/NASA/NSF Astronomers have detected the 'biggest explosion since the big bang' using high power telescopes: NASA's Chandra X-ray Observatory, the ESA's XMM-Newton, the Giant Metrewave Radio Telescope in India and the Murchison Widefield Array in Australia. This explosion has easily surpassed the previous record held by an eruption from a cluster named MS 0735.6+7421 in which 'a mass of about 300 million Suns was swallowed'. This latest outburst is said to be 'five times bigger than any other known explosion'. Calculations suggest that approximately 5 x 10 54  Joules of energy would be required to cause an explosion of this magnitude. The calculated amount of energy involved is around 9 x 10 33  times more than annual global energy consumption (5.8 x 10 20  Joules). The explosion was ...