Meteorites - Hot Rocks From Space
Meteorites are natural fragments of rock or metal which fall to Earth from space. Thousands of tonnes of extraterrestrial material falls to Earth every year. Most falls in the form of cosmic dust, but a surprising number of larger meteorites do reach the Earth's surface. Captured in Earth's gravitational field they are pulled down at incredible speed, burning up in a fireball in the atmosphere before crashing into the ground.
Looking at our nearest neighbour the Moon on a clear night gives you some idea of how planets are constantly bombarded by meteorites. Because the surface of the Moon barely changes, hundreds of craters from millions of years of impacts are still visible, whereas the constantly changing surface of our Earth has hidden most of the craters which are evidence of our own history of impacts.
A Bit Of Space In Yorkshire
Meteorites fall randomly over the Earth, the vast majority fall into the oceans and desert areas which cover so much of our planet. Very few meteorites are recovered and recorded, and fewer still are actually witnessed as they fall. Several meteorites have fallen in the UK, including right here in Yorkshire. One of the most famous was the 'Wold Cottage Meteorite' which fell in Wold Newton in the Yorkshire Wolds on December 13th, 1795. It is one of the largest meteorites ever recorded to have fallen in Britain, and what made this meteorite even more important is that the fall and impact was witnessed by several people stood only metres from the impact site. They reported sparks of fire coming from the meteorite as it flew through the atmosphere, before burying itself into the ground and showering the onlookers with earth. They retrieved the meteorite from its crater, still warm from its entry through the atmosphere. The Wold Cottage Meteorite is known as a Stony Meteorite, like this one
here in our collection.
A Glimpse At The Very Beginning
Most meteorites are fragments broken from asteroids when they collide in space, whilst some are thought to come from our Moon and the planet Mars. Asteroids are the material left over from when the planets were forming at the birth of our Solar System, nearly 4.6 billion years ago, and so meteorites are fragments of this primitive material. There are thousands of asteroids in our Solar System, most orbiting the Sun in the Asteroid Belt between Mars and Jupiter. The larger asteroids have layered interiors much like the Earth, with an iron-rich central core made of metal, a mantle and a rocky crust. Each of these layers yields the three main types of meteorite: Iron meteorites from the core, Stony-Iron meteorites from the mantle around the core and Stony meteorites from the rocky crust.
Meteorites are very important to our understanding of the history of the Earth and our Solar System. They contain clues about what it might have been like in those swirling clouds of dust and gas when the Solar System was born nearly 4.6 billion years ago, and some contain particles thought to be even older than our Solar System. The Iron meteorites like this one here in our collection provide the only material we have for directly studying what the core of our own planet might be like, which otherwise is inaccessable to us.