Meteorites found on Earth typically are sourced to three asteroid families which are all located in the main asteroid belt between Mars and Jupiter. These families are identified as Massalia, Karin and Koronis.

According to ScienceAlert a new set of astronomical studies from three research teams has determined that “more than 90 percent of meteorites” can be sourced from this region. The three teams are from the:

• French National Centre for Scientific Research
• The European Southern Observatory
• Charles University in the Czech Republic

Meteors are typically “made up of small particles called chondrules, caused by the rapid cooling of molten rock.” The set of studies focused on H (high iron) and L (low iron) chondrites which account for approximately 70% of meteorites.

As the study points out, “Massalia saw major collisions 466 million years ago and 40 million years ago, while the Karin and Koronis families experienced collisions about 5.8 and about 7.6 million years ago, respectively.

These collisions lead to the conclusion that “most meteorites that strike Earth today are from fewer asteroid groups than might have been expected.”

The complete research has been published in Nature and Astronomy and Astronomy & Astrophysics.

Read the entire study here:  ScienceAlert.

This got me to wondering about meteors from beyond our own solar system. The meteor Oumuamua is the first confirmed object from another star to appear in our solar system. Its closest approach distance was recorded at 0.16175 AU, or 15,036,000 miles from Earth on 10/14/17. Astronomers calculate it took 600,000 years for Oumuamua to reach our solar system from the star Vega in the constellation Lyra.

But Oumuamua was not the first interstellar meteor. According to “Spy Satellites Confirmed Our Discovery of the First Meteor from beyond the Solar System,” (Space & Physics | Scientific American), on 1/8/14 a meter-sized rock was streaking across “the sky off the coast of Manus Island, Papua New Guinea…and raining debris into the depths of the Pacific Ocean.” Department of Defense and NASA data was classified for years, but finally in March/April, 2022, official confirmation was made by the US Space Force and the Space Operations Command, confirming that the meteor CNEOS 2014-01-08 was, in fact, of interstellar origin. This meteor predates Oumuamua by a few years, 2014 to 2017.

According to Meteors and Meteorites: Facts – NASA Science, 99.8% of meteorites come from asteroids and the remaining 0.2% come from meteorites from Mars or the Moon. “There are 60 known Martian meteorites [that] were blasted off the surface of Mars by meteoroid impacts. All are igneous rocks crystallized from magma.” Another 80 lunar meteorites are “similar in mineralogy and composition to Apollo mission Moon rocks.” “Small pieces of Mercury or Venus could have also reached Earth, but none have been conclusively identified.”

Scientists estimate that ”about 48.5 tons of meteoritic material falls on Earth each day (ibid).

The University of Manchester estimates that 17,000 meteorites fall to Earth each year. However, Live Science estimates there are probably “6,100 meteorite falls per year over the entire Earth.”

According to Britannica, “When a meteoroid enters Earth’s atmosphere, it is traveling at very high velocity – more than 11 km per second (25,000 miles per hour) at minimum, which is many times faster than a bullet leaving a gun barrel. Frictional heating, produced by the meteoroid’s energetic collision with atmospheric atoms and molecules, causes its surface to melt and vaporize and also heats the air around it. The result is the luminous phenomenon recognized as a meteor. Popular synonyms for meteors include shooting stars and falling stars. The vast majority of meteoroids that collide with Earth burn up in the upper atmosphere. If a meteoroid survives its fiery plunge through the atmosphere and lands on Earth’s surface, the object is known as a meteorite.”

Is there any evidence of any meteors arriving here from another galaxy? A search of NASA.gov revealed no articles or references to meteors from other galaxies. Astronomers report that the majority of meteorites come from the Asteroid Belt located between Mars and Jupiter. So far, there is zero evidence of any rocks or debris coming from even our closest galaxy neighbor, Andromeda.

Chris Ebel
10/17/24

Photo credit: @adamci