Meteoroid that strikes earth11/14/2022 ![]() The pioneering 18th-century concept of uniformitarianism as a central tenet of geology, in which change occurs gradually, has given way to the idea that periodic cataclysmic impact events have greatly affected the origin and geological evolution of Earth, its climate, and the habitability of our planet. Meteorite impacts as a planetary processĭuring the latter part of the 20th century, the realisation that asteroids and comets have struck, and continue to strike, the Earth throughout time has revolutionised our understanding of how the Earth and other solar system objects formed and evolved over the past 4.5 billion years. These objects are not slowed down by the Earth’s atmosphere and instead deposit a huge amount of energy at a single point in the Earth’s crust to form hypervelocity impact craters. When one of these objects approaches the Earth, they do so at staggering velocities: with averages of 15 – 20 km/sec for an asteroid and over 70 km/sec for comets. This is not the case for objects greater than a few 10s of metres in diameter! There are literally thousands of asteroids and comets larger than 50 m and up to 100s of kilometres in size scattered throughout our Solar System. Most meteorites cause very little damage, with only the occasional broken window or roof typically being reported. For anybody lucky enough to find these space rocks, we refer to them as meteorites. As the size of a particle increases – up to 10s of centimetres to perhaps a metre or two – there is a high likelihood that all or part of it will remain more-or-less intact and survive passage through the atmosphere, being slowed down and landing on the Earth’s surface at low velocity. Technically known as meteors, shooting stars are bright streaks across the night sky formed when pieces of dust and small millimetre to centimetre-size particles from space burn up harmlessly in Earth’s atmosphere. One of the most magical moments on a clear, dark night, is to witness a shooting star. Osinski, Professor at Western University, explores the positive and negative impacts meteorites have on Earth Impact Earth ![]()
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