By Savithri Rodrigo
Melbourne, Australia (Commonwealth Union)_A rock weighing a whopping 17 kilograms was found recently to be a 4.6 billion year old meteorite, now named the Maryborough meteorite after the town near Melbourne, Australia, in which it was discovered. This is the 17 meteorite found in the state of Victoria where thousands of gold nuggets have been found but are considered much rarer than gold and therefore more valuable to science. It is the second largest chondritic mass, the largest being a 55 kilogram meteorite found in 2003.
However, the story of the rock goes back to 2015 when a prospective gold digger found a very heavy rock with a reddish hue surrounded by yellow clay. Gold explorers work in and around the Goldfields region, which gained popularity during the gold rush of the 19th century. They arm themselves with metal detectors to prompt the presence of gold while on their quest.
David Hole was the man who found this unusual rock, which when his metal detector beeped picked it up and thanked his good fortune. However, fortune didn’t come easy. The piece he held in his hand was literally as hard as rock.
He used a rock saw, angle grinder, a drill, a sledgehammer and even doused the rock in acid to no avail. The rock did not crack. In exasperation, he took it to the Melbourne Museum. What was revealed was that this piece of rock he found was no gold nugget, but rather a rare meteorite.
Melbourne Museum’s Geologist Dermot Henry explains that meteorites are formed when they travel through the atmosphere and as they melt on the outside the atmosphere sculpts them. However, meteorites are not as common as thought because Henry stated that in his 37 years of work examining thousands of rocks, only two had turned out to be meteorites and this was one.
Normally a rock this size won’t be that heavy and hence that was the first clue on what it could have been. A diamond saw had to be used to cut off a small slice to discover its composition which had a high percentage of iron, making it a H5 Ordinary Chondrite. The tiny crystallised droplets of metallic minerals found within are called chondrules.
Meteorites are the cheapest form of space exploration as they have clues on age, formation and chemistry of the solar system. Some even allow a glimpse of the interior of planet earth, while in others there is stardust even older than our solar system, shedding light on how stars form and evolve. There are also rare meteorites that contain organic molecules like amino acids that are the building blocks of life.
