Earth is struck by thousands of meteorites each year, according to a 2020 survey published in Geology — but they’re small meteorites, not planet-changing asteroids. And with these meteorites come a host of elements that are the key building blocks for life on Earth.
Until now, researchers believed that volatile elements such as zinc and water may have come from asteroids that formed near Earth. However, a a new study published in the journal Science shows that these volatiles may have come from asteroids originating closer to Jupiter, Saturn and Uranus.
Although these small stones have made a long journey through space, they have greatly changed our planet. This is what meteorites bring to Earth.
What is the difference between asteroids, meteors, and meteorites?
If the volatiles come from asteroids, then why do they also arrive on Earth in meteorites? When it comes to space rocks, there can be some confusion between asteroids, meteoroids, meteors, and meteorites—and that’s without including comets.
According to NASA, asteroids are airless rocks smaller than planets but larger than space rocks that normally make their way through Earth’s atmosphere. They are probably the remnants of the formation of our solar system. Asteroids are often found in asteroid belt — a region between Mars and Jupiter — though some are closer to Earth. Some asteroids are large enough to have their own “satellites” or objects in their orbit.
Read more: 4 facts about asteroids you may not have known
Occasionally, two asteroids can collide, breaking off a small piece of rock or dust that floats through our solar system. The broken piece is called a meteoroid.
According to Jet Engine Laboratory from California Institute of Technologymeteoroids can also be debris from planets and comets.
Although meteoroid fragments are small, they can be seen with the naked eye as they turn into meteors this streak across the night sky after entering Earth’s atmosphere. When multiple meteors fall to Earth, they form a meteor shower.
meteorites, however, are the space rocks that fall through the Earth’s atmosphere and actually reach the ground. And while meteor showers seem to produce many meteorites, the opposite is true.
Elements brought to Earth by meteorites
Meteorites can be rich in elements such as metals and silicate crystals. According to Museum of Natural History there are three types of meteorites in London: iron, stony and stony-iron.
Iron meteorites usually contain iron-nickel metal and traces of sulphide and carbide minerals. Experts believe that these meteorites are part of an asteroid core that has melted.
(Credit: MikhailSh/Shutterstock)
Stone meteorites contain mostly silicate minerals and are the most common type of meteorite discovered.
(Credit: IamTK/Shutterstock) Chondrite meteorite
Stone-iron meteorites usually consist of equal parts iron-nickel and silicate minerals — which may include semi-precious items Gems such as olivine.
(Credit: Adwo/Shutterstock) Imilac pallasite meteorites
The right item
As the recent study suggests, meteorites may be responsible for bringing volatile elements like water and zinc to our planet from beyond the asteroid belt. Volatile substances are “elements or compounds that change from a solid or liquid state to a vapor at relatively low temperatures,” according to press release.
“This contribution of material from the outer solar system played a vital role in establishing Earth’s stock of volatile chemicals,” says the study’s senior author Mark Rekemper in a press release. “It appears that without the contribution of material from the outer solar system, Earth would have much less volatile matter than we know it today – making it drier and potentially unable to nurture and support life.”
These meteorites contain six most common elements found in living things: oxygen, carbon, hydrogen, nitrogen, calcium and phosphorus. These six elements, combined with other volatiles such as water and zinc, may have helped establish life as we know it.
Although the elements found in meteorites are also found on Earth, the addition of these elements and compounds from our solar system may have helped make our planet habitable. Space rocks continue to help scientists better understand the origins of our solar system and how planets form. Although these meteorites may not have left large impact craters, they did impact Earth in other ways.
Read more: This is what meteors look like flying towards Earth from space