Sixteen years after it landed on Earth, scientists finally think they have identified the origin of a meteorite that is truly out of this world. Dubbed the Tagish Lake meteorite, named for the region of British Columbia where it landed in 2000, the specimen is quite different from most meteorites documented by science. Now, researchers who have been evaluating the rock’s composition say they have a better idea of where it came from, and the results are a bit surprising.
Most of the meteorites known to man originated from the asteroid belt between Mars and Jupiter, which are close neighbors in the celestial sense. The Tagish Lake meteorite, though, is suspected to have traveled from the Kuiper Belt, the ring of rocks residing past the orbit of Neptune in the outer solar system. The belt is 30 to 50 times Earth’s distance from the sun, or 2.5 to 4.5 billion miles (4.5 to 7.4 billion kilometers). If the theory is correct, this marks the first time in scientific history that a meteorite from the outer solar system has been identified.
Scientists at the Southwest Research Institute in Boulder, Colorado have been studying the meteorite for years to determine its origin. The rock’s composition is similar, but not identical, to those stemming from the Mars-Jupiter asteroid belt. It is comprised mostly of carbon, but has a higher concentration of amino acids (the building blocks of protein) than other cataloged meteorites. Some pieces of the Tagish Lake specimen have 10 to 100 times more amino acids than others, which scientists have known for several years but didn’t quite understand until more recently.
Linking the meteorite to the Kuiper Belt is happening right on time, though, as NASA approved an extension of the New Horizons mission earlier this summer to explore an object in the asteroid belt known as 2014 MU69. It’s really quite a trek, though, and the unmanned spacecraft isn’t expected to reach its destination until January 1, 2019. Perhaps then, we will learn more about the mysterious rock that landed in Canada nearly two decades earlier.
Results of the study were recently published in The Astronomical Journal.