A meteorite has hit the Earth at Winchcombe, England, leaving an 18-foot-wide crater. An initial examination of the rock found a high water concentration, meaning it could have come from outer space. It bolsters theories that Earth’s water could have come from asteroids and comets breaking up in the atmosphere, not just from ice sheets and rainwater.
The Winchcombe meteorite, first discovered in 1819, is thought to be from the asteroid Ceres and weighs about 1.4 tons. It fell on February 15, 1819, when the Earth was moving through space at about 28,000 miles per hour.
The rock hit at Winchcombe in Gloucestershire at about 6:00 am and broke into three pieces for 50 yards of a half-mile deep crater measuring 18×3 feet (5×1 meters). A long section of this crater is filled in by sediment and clay at the bottom.
Scientists found evidence of water inside the rock, apparently confirming their theory that comets and asteroids provided Earth with its water. The study confirmed the presence of carbonates, clay minerals, which can only form in water, and high iron content. The high iron content also suggests that the meteorite could have come from an asteroid rather than a comet because comets tend to be made of ice and are, therefore, low in iron. Professor Hetherington leads the research: “This supports the idea that much of the Earth’s oceans may have come from impacts by comets and asteroids with our planet.”
Scientists think a meteorite similar to the one found could have collided with Earth around 4.5 billion years ago. It would have left enough water to fill the oceans and provide all of Earth’s water, so there would be no need for comets or asteroids to provide Earth with water. However, some may say that such an impact could not have occurred because there is no evidence. Still, Professor Hetherington disagrees: “We do not find any evidence of cratering before 3.8 billion years ago, which is when we think life first appeared on our planet. But some people believe there was a major bombardment in the second half of the heavy bombardment period – more than 3.8 billion years ago. It is where we got the moon and Mars, and Venus. It could have brought comets like iron’s 26-kilometer object, which is likely a type of asteroid, and rocks similar to those in the Winchcombe meteorite.”
Researchers are still looking into exactly how much water was in the meteorite. But they expect it to be more than 15 percent of its weight.
The rock fell in Winchcombe, England, on February 29 last year. A farmer called Bob Heslewood spotted it while driving past his land. He alerted the police, and they sent the meteorite to a laboratory at the University of Oxford, where the study was led. A scientist who helped examine the rock said: “I was stunned when I opened the rock up and saw its size. It’s incredible that it had weathered so well, being buried for almost a hundred million years and yet still retained so much of its original material – this made this rock very special.”
The meteorite may also help scientists study the web of life on Earth. The white circles inside the meteorite are a mineral called carbonates, which are forms of limestone and would not have formed on Earth. The Winchcombe rock is one of 22 meteorites thrown out of the asteroid belt around 4 billion years ago and hit Earth. It is a similar distance to Jupiter and Saturn but much closer to the sun. The rock is likely to be very similar to rocks in the asteroid belt, which scientists are keen to study as they think they could hold clues as to where life on Earth began.