Context: On August 17, 2022, a meteorite streaked over India, breaking apart as it descended through the air, to scatter over two villages in Banaskantha, Gujarat. An analysis by a group of scientists at the Physical Research Laboratory (PRL), Ahmedabad has revealed that the meteorite is a “rare, unique specimen” of aubrite.
What is meteorite?
- A meteorite is a solid piece of debris from an object, such as a comet, asteroid, or meteoroid, that originates in outer space and survives its passage through the atmosphere to reach the surface of a planet or moon.
What is the difference between a meteor, a meteorite, a meteoroid and an asteroid?
- An asteroid is a relatively small body, usually rocky or metallic, composed of dirt and ice. Small asteroids are also called meteoroids. When an asteroid or meteoroid enters the atmosphere and streaks through the sky, it then becomes known as a meteor. Anything that survives the impact is a meteorite.
- Meteorites that are recovered after being observed as they transit the atmosphere and impact the Earth are called meteorite falls. All others are known as meteorite finds.
What are the Types of meteorites?
- Meteorites have traditionally been divided into three broad categories :
- Stony meteorites that are rocks, mainly composed of silicate minerals;
- Iron meteorites that are largely composed of ferronickel; and
- Stony-iron meteorites that contain large amounts of both metallic and rocky material.
- Modern classification schemes divide meteorites into groups according to their structure, chemical and isotopic composition and mineralogy.
- “Meteorites” less than ~1 mm in diameter are classified as micrometeorites, however, micrometeorites differ from meteorites in that they typically melt completely in the atmosphere and fall to Earth as quenched droplets.
- Extra-terrestrial meteorites have been found on the Moon and on Mars.
What are the impacts of Meteorites?
- When the original object enters the atmosphere, various factors such as friction, pressure, and chemical interactions with the atmospheric gases cause it to heat up and radiate energy. It then becomes a meteor and forms a fireball, also known as a shooting star. Once it settles on the larger body’s surface, the meteor becomes a meteorite. Meteorites vary greatly in size. For geologists, a bolide is a meteorite large enough to create an impact crater.
What are the importance of meteorites?
- Some meteorites contain grains of dust (“stardust”) that were produced by stars before the formation of our Solar System. Studies of these pre solar grains can increase our understanding of star formation and evolution.
- The elements present in the meteorite gives an idea about the age and bulk chemical composition of the Solar System
- Meteorites may have brought to Earth the components necessary for life – organic compounds such as carboxylic acids, complex amino acids, aliphatic amines, acetic acid and formic acid can be transported great distances inside space rocks. Additionally, large meteorite impacts, like the one ~65 million years ago that killed off the dinosaurs, can lead to major extinctions and influence the course of life on our planet.
What is Aubrite Meteorite?
- Aubrite meteorite is a coarse-grained igneous rock that formed in oxygen-poor conditions, and thus “contain a variety of exotic minerals that are not found on Earth.
- Aubrites are a type of achondritic (or achondrite) stony meteorite, which means they do not contain chondrules, or small spherical grains of mineral that are common in other types of meteorites.
- Worldwide, aubrites have crashed in at least 12 locations since 1836, including three in Africa and six in the U.S.
- Aubrites originate from an extremely reduced differentiated parent body in our solar system. They are named after the Aubres meteorite, which fell in France in 1836 and was the first known example of this type of meteorite.
- Worldwide, aubrites have crashed in at least 12 locations since 1836, including three in Africa and six in the U.S.
India and Aurbite Meteor
- The rare aubrite was uncovered earlier in India only in Bustee fall in 1852 in Gorakhpur, Uttar Pradesh.
- On August 17, 2022, the meteorites fell in Diyodar taluka in Gujarat. They have been named the Diyodar meteorites.
- As per reports, the villagers did not notice any trail but heard a booming sound, which reportedly resembled the noise of a jet plane passing by.
- One big fragment fell in Diyodar, while the other dropped in Ravel village.
- The villagers amassed the large pieces, which weighed around 200 grammes and passed them to scientists from the Physical Research Laboratory.
Key Findings
- Researchers conducted reflectance spectroscopy to examine pieces of the meteor, which was found to have magnesium-rich pyroxene.
- The team polished a few small chips (0.5–1.5 cm) from the larger fragment of the Diyodar meteorite to conduct chemical analysis.
- The examination showed that the meteorite is a unique specimen of aubrite, a rare achondrite batch of meteorites.
- Aubrites contain sulphides of sodium, titanium, manganese, chromium and calcium – all normal lithophiles. Over these, it also has silicon-bearing FeNi metal.
- They share a similar highly reduced nature, unusual mineralogy, and oxygen-isotopic composition with enstatite chondrites.