Scientists reexamined halogen levels in ancient meteorite samples. Photo by University of Manchester
Dec. 5 (UPI) -- New analysis confirms the meteorites that formed Earth delivered just the right amount of salt to support life.
Naturally occurring salts called halogens, including chlorine, bromine and iodine, are needed to support life. High concentrations of salts, however, can prohibit life.
Previous analysis of the meteorites that formed Earth revealed high levels of halogens. Until now, scientists couldn't explain the discrepancy between Earth's life-friendly salt concentration and the large halogen amounts found in the earliest meteorite samples.
According to new research by scientists at the universities of Manchester and Oxford, previous halogen estimates were flawed. Analysis of 4.6 billion-year-old chondrite meteorites revealed moderate halogen levels.
"These kinds of meteorites are remnants of the solar nebula, a molecular cloud made up of interstellar dust and hydrogen gas that predates our solar system," Manchester researcher Patricia Clay said in a news release. "Studying them provides important clues for our understanding of the origin and age of the solar system."
Scientists devised a new measurement technique to ensure their meteorite samples weren't contaminated. The results -- detailed in the journal Nature -- proved previous measurements were simply too high.
"No single model of Earth formation using the old meteorite measurements could easily account for the halogens we see today," Clay said. "Some of these models needed catastrophic planetary wide removal of halogens without affecting related elements -- which just didn't make sense."
Scientists were able to create a new model of Earth's early composition. Researchers believe their new and improved model will help scientists study the ways early Earth acquired the volatile elements that made the emergence of life possible.
Researchers were surprised to find the halogen levels among the different types of ancient meteorites were very similar.
"This is an incredibly important picture into the processes that formed the meteorites themselves," Oxford researcher Chris Ballentine said. "But [it] also means that whatever meteorites formed the earth the halogen ingredients for Earth's recipe remains the same."