Posted by KeighleyAstro on Dec 18, 2023 in Main |

The topic of discussion at the December meeting of Keighley Astronomical society was the discovery of a meteorite that fell to Earth at 3.35pm on 14th March 1881. The guest presenter was Mr Martin Lunn FRAS. Mr Lunn introduced himself to the members and explained that he had been employed as the curator of astronomy at the York Museum before his retirement. One the ‘star’ objects in the Yorkshire Museum’s collections was a literal shooting star.

Mr Lunn explained what a meteorite is and in simplest terms, it is a rock that falls to Earth from space. Meteorites are rocks, but they are not like Earth rocks. Most are far older, and they provide some of the only samples we have of other worlds; other planets, asteroids and possibly comets in our solar system.

Mr Lunn explained that all meteorites come from inside our solar system. Meteorites in the immediate area of the Earths transit path around the Sun were cleared by the Earths gravity a long time ago.

Most meteorites are fragments of asteroids that broke apart long ago in the asteroid belt, located between Mars and Jupiter. Such fragments orbit the Sun for some time, often millions of years before colliding with Earth. Other meteorites originate from the ort cloud the lies on the outer edge of the solar system and in the area between the Sun and the orbit of the planet Mercury.

Meteors and meteorites have had in the past a devastating impact of life on Earth. The age of the dinosaurs came to the end with a very large impact, which hit the Yucatán Peninsula in Mexico. The asteroid is thought to have been between 10 and 15 kilometres wide, but the velocity of its collision caused the creation of a much larger crater, 150 kilometres in diameter. It’s the second-largest crater on the planet.

Mr Lunn went on the say that there is evidence of destructive meteors being recorded in the old testament of the bible. The great flood that saw Noah build his famous Ark was caused by a large impact that hit the northern Mediterranean are and caused a devastating tsunami.

An Ancient Middle Eastern City Destroyed by a Meteor May Have Inspired the Bible’s Tale of Sodom and Gomorrah, a New Study Says. Experts have been studying the remains of the city of Tall El-Hammam remains for 15 years.

Archaeologists studying the ruins Tall el-Hamman found what they called the destruction layer: A mix of charcoal, ash, and melted pottery that was five feet thick. The kind of devastation that comes from superheated temperatures of a firestorm, ruling out human warfare and other natural disasters such as a volcano, earthquake, fire, or tornado as its cause.
The team used a tool developed by impact experts, to model scenarios that matched the physical evidence, compared to the effects of known impact events and nuclear detonations. Of the 17 observations, only a meteor matched all the data.

A cosmic airburst sounds like an otherworldly event, but other instances have been documented, such the explosion over Tunguska, Russia, in 1908. Such explosions are rare, with thousands of years between known events. Tall el-Hamman is the second-earliest airburst to be identified, after one in Abu Hureyra, Syria, which experts believe was destroyed by a comet some 12,800 years ago, and may represent the first written record of such a catastrophic event.

The Tall el-Hamman meteor was probably larger than the one that struck Tunguska, but no bigger than 200 to 250 feet across.

Thankfully the meteorite that was found in Middlesbrough on 14th March 1881 was much smaller.

The Middlesbrough meteorite is classified as a ‘chondrite’; it is approximately 4.5 billion years old and was formed at the same time as the Earth and the solar system. It is approximately 6 inches in diameter, weighs 3 pounds 8.75 ounces (approximately 1.5 kg) and has a crust of unusual thickness. It was recovered intact.

A chondrite is a stony non- metallic meteorite that has not been modified by either melting of differentiation. They are formed when various types of dust and small grains in the early Solar System accreted to form primitive asteroids. So they are of great age and are important to science.

The story of this particular meteorite starts with four railway employees working at a location on the rail track owned by the North Eastern railway at Pennyman’s Siding. The present location is the site of the Captain Cook memorial Hospital.

Their work was interrupted by a ‘rushing or roaring sound overhead’, followed by a thud. Confused, they went to try and find the source. What they discovered was a hole about a foot deep in the railway ballast about 15 metres from them.

They reached into the hole and found an object, which they described as “new milk warm”. They assumed it must be a piece of slag ejected from a passing locomotive.

Ten days later Victorian scientists, including the famous astronomer Alexander Herschel, recognised the importance of the meteorite and it was carefully excavated and preserved in a box. He examined it and excitedly declared: ‘the unusual looking stony fragment is really a genuine meteorite of an exceptionally perfect description and appearance.’

Hershel identified it as an ‘aërolite’ (This was an early name given to describe a meteorite) or ‘stony’ meteorite, which meant that it had been formed at the same time as the Earth and the Solar System, thrown out into space as part of the process.

The natural history Museum in London apparently wanted it for its collection. But the North East Railway Company wanted to take possession of it to display in their newly constructed head office. The dispute reached the point where solicitors and lawyers were representing both parties. The legal conclusion was that as the meteorite had been found on the property owned by the railway company; they had rightful ownership of it.

How did the North Eastern railway company deal with this successful acquisition? They deemed the meteorite ‘lost property’, and as per their own standing orders if no person claims the lost item after six months, the railway company have full title to possession.

Therefore they insisted that it stayed in Yorkshire, and the directors of the company decided to present it to the Yorkshire Philosophical Society, the founders of the Yorkshire Museum, on 16th September 1881.

The Yorkshire Museum was the only Museum in Yorkshire and up until 1974; Middlesbrough was in the North Ridding of Yorkshire.

The meteorite has remained at the Yorkshire Museum ever since. Even though the meteorite itself is in the Yorkshire Museum, small samples were taken from it shortly after it fell. These are now in the collections of the Natural History Museum in London, the Natural History Museum of Vienna, the American Museum of Natural History in New York, and the Field Museum of Natural History in Chicago.

Although the Middlesbrough Meteorite is not a very rare type chemically (around 90 per cent of known meteorite finds are stony ‘chondrites’ like this), it is a very special example.

Mr Lunn explained; firstly, meteorites heard to fall are incredibly rare, and only a handful are recovered every year worldwide. This gives us information on the trajectory and nature of the meteorite’s journey. The Yorkshire Museum even holds a cast of the hole that the impact made. Because the meteorite landed in railway ballast next to the track, it made a narrow and deep hole, rather than a crater that most people might expect.
Herschel calculated the speed of impact as about 281 miles per hour! The railway workers must have been pleased that they weren’t any closer to it when it fell.

By experimentation, replicating the conditions of the impact, Herschel determined the speed of the object at the time was 412 feet per second (281 mph). This result was viewed as partial confirmation of a theory of the Italian astronomer Giovanni Schiaparelli that meteorites lost most of their cosmic velocity (the velocity they had before entering the Earth’s atmosphere), due to air resistance at a high altitude in the atmosphere.

Secondly, the shape of the meteorite is very unusual. It is roughly conical and scored with deep grooves. This reflects the fact that it didn’t tumble as it came through the Earth’s atmosphere.

Usually, meteorites form very irregular shapes as they twist and turn and break up on their journey. Instead the dark outer coating on the Middlesbrough Meteorite, known as the fusion crust, reflects how it was melted and moulded in one orientation as it shot through the atmosphere and was heated to thousands of degrees.

The shape of the Middlesbrough Meteorite is so special that the European space agency scanned it into its database in 2010, so that future missions to Mars will be able to recognise similar meteorites on its surface.

Martin Lunn, curator of astronomy at the museum at that time, said: “The scientists are coming to the museum to catalogue it with the latest 3D mapping technology.
“We are delighted that an artefact from the Yorkshire Museum will be helping the Europe and Americas space programme, and it is fascinating to think that when they launch the probe into outer space there will be information from our meteorite on board.”

When the meteorite fell in 1881 it caused a stir as a small piece of the Solar System crashed into the lives of four ordinary men in North Yorkshire !!