Meteorites are often heavier than rocks, can attract magnets, and bear characteristic heat marks as they plunge through the atmosphere.
Close-up on Hoba, one of the largest meteorites ever discovered.
Close-up on Hoba, one of the largest meteorites ever discovered. (Photo: Voyage Telly).
Meteor fragments often come from asteroids or comets, crash into the atmosphere, and land on the ground. There are three main types of meteorites: iron, ironstone and stone. Each type can be divided into smaller groups based on mineral content, structure and chemical composition. Some types of meteorites, like chondrites, can be more than 4.5 billion years old and are extremely rare, but more common types, like iron meteorites, appear quite frequently.
So how do you distinguish meteorites from ordinary rocks? One way to check is measure density. Meteorites contain iron and other dense materials, synonymous they will be much heavier than a normal stone of the same size.
Meteors containing a lot of iron are magnetic and therefore often attract magnets. However, this is not an immutable rule because some rare meteorites are not magnetic.
Unlike normal rocks born from Earth, meteorites have many strange shapes after being heated by the atmosphere. They may even have unusual imprints on the surface called regmaglypte, looks a bit like the fingerprints a potter leaves in wet clay. These bumps appear when the outer layer of the meteorite melts as it descends toward the Earth’s surface.
This process can even create a shell covering the surface of the meteorite called melted shell, which looks like a black eggshell. The surface of a new meteorite is often shiny due to the impact of a high-speed run through Earth’s atmosphere. If it falls for longer, the meteorite may turn brown as the iron begins to rust.
Furthermore, flowing streaks – the ultra-fine lines formed by molten meteorites as they enter the atmosphere, which can even be smaller and finer than a human hair – are also an identifying feature of meteorites.
Flow striations on the iron meteorite Taza (NWA 859).
Flow striations on the iron meteorite Taza (NWA 859). (Photo: Geoff Notkin)
Besides work Magnetic testthe person who discovers the suspicious stone can also come forward Check for scratches. After rubbing on an unglazed ceramic surface, the meteorite leaves no traces. Rocks that leave black or red streaks likely contain magnetite or hematite, minerals not typically found in meteorites. However, this method is not absolutely precise because some types of stones do not leave marks.
If resources are sufficient, the person who discovered the stone can drill a hole in the specimen and see if there are any shiny pieces of metal. This could be a sign that this stone comes from space.
People can also use the exclusion method to distinguish meteorites from ordinary rocks. Meteorites do not contain crystals like quartz. Most quartz forms from cold magma, not from space.
Volcanic rock sometimes contain bubbles from this cooling process, but meteorites do not contain bubbles inside. Likewise, meteorites generally do not contain vesicles – tiny voids often found in volcanic rocks such as pumice.
Laboratory testing is one way to get more precise answers about meteorites. Iron is made by man from metallurgical process (called metallurgical slag) sometimes confused with meteorites, but this confusion can be avoided by testing for the presence of nickel. Earthly iron generally does not contain nickel, while meteoric iron from space contains at least small amounts of pure nickel.
Article source: VnExpress
If there is an error with the article How to Tell Meteorites From Normal Rocks, or if the content is incorrect, please contact us so we can correct it.
Keyword:
Meteorites are often heavier than rocks, can attract magnets, and bear characteristic heat marks as they plunge through the atmosphere.
