Meteorites are fragments of rock and iron that originate from outer space and have survived entry through our protective atmosphere to land on Earth’s surface. Our planet is bombarded daily with material from outer space with estimates ranging from 20,000 to 60,000 tonnes falling on Earths surface each year! Most of this falls as tiny dust sized particles but some are larger, from pea size through to multi kilogram individuals. Much larger multi tonne meteorites even have the potential to bring death and destruction to our planet. Numerous large crater forming meteorites have changed the course of evolution, wiping out certain animal groups such as the dinosaurs and helping create new conditions to facilitate the progress of others. However meteorites may also be responsible for sowing the seeds of life on Earth, possibly bringing water and organic compounds that could have kicked off the chain of evolution of life on Earth!
Meteorites can fall at any time and can land anywhere. Given that three quarters of the Earth’s surface area is covered in water and meteorites fall pretty much anywhere then a large proportion of them fall unwitnessed and unrecovereable in the sea. Also a lot fall in remote areas where they are not witnessed, so it’s not surprising that actually very few new meteorites are recovered each year.
Meteorites mostly originate from asteroids although some come from the Moon and Mars. Some possibly even originate from other planets and comets. When asteroids collide, either with another asteroid or with a larger planetary body then debris from both is ejected into space. These ejected fragments can then get caught in the gravitational pull from other large asteroids, planets or moons. They are then sent in new less stable orbits which means that they can collide with other planetary bodies, including Earth.
Throughout history meteorites have captured our imagination and they have been seen as portentous omens, both good and bad. ‘Iron from the sky’ was used by ancient peoples all over the world from the Arctic to the Sahara with evidence found of meteorites being used to make tools and weapons. They have been found in tombs and burial chambers, with obvious reverence given to them by the people who placed them there. Falling from the sky, shrouded by myth and superstition, many believed them to be sacred objects and they were often venerated and worshipped as such.
Some meteorites are actually the oldest rock that is known to us and contain inclusions that predate the formation of Earth and our solar system. Meteorites are a window into the past and their study today has helped to unlock some of the secrets of the formation of our solar system, the universe and even the origins of life on Earth.
Meteorites are collected today not only as important objects scientifically but also as beautiful and fascinating specimens in their own right. To be able to hold in your hand a mysterious rock that is older than the Earth itself evokes a huge feeling of wonder and gives you great perspective on the huge scale of the Universe both spatially and in its immense age. To put it very simply, meteorites are amazing! If you want to see all that I have written above shown much more eloquently in a visual format then please take 4 minutes to view the below video, very aptly titled ‘The wonder of meteorites’. Thanks very much to Jeff Kuyken from Meteorites Australia for producing this video in the first place and then for allowing me to post it here. Also for more in depth information please see the links at the top of this page.