Asteroid Itokawa continues to captivate researchers with its intriguing secrets. Recent findings by a team at the University of Arizona have unveiled a surprising discovery—common salt crystals. These crystals, resembling the ones found on your table at home, could only have formed in the presence of water. The study’s senior author, Professor Tom Zega, described them as “nice, square crystals” that sparked lively discussions among the research group due to their unexpected nature.
What makes this revelation even more remarkable is that the sample in question comes from an ordinary chondrite—a stony meteorite derived from the peanut-shaped near-Earth asteroid Itokawa. Itokawa is believed to have originated from a larger parent body and stretches about 2,000 feet (610 m) in length. S-type asteroids like Itokawa are typically composed of rock and are not known to contain water-bearing minerals.
According to Zega, “It has long been thought that ordinary chondrites are an unlikely source of water on Earth. Our discovery of sodium chloride tells us this asteroid population could harbor much more water than we thought.” Although sodium chloride has been previously detected in samples sourced from Itokawa, there were concerns about contamination from Earth. However, this particular sample, collected by the Japanese Hayabusa spacecraft and diligently protected from contaminants, confirmed that the salt crystals originated from Itokawa itself.
To ensure the sample’s integrity, rigorous testing ruled out contamination from storage or human sources. Control testing on terrestrial rocks also showed no signs of the sodium chloride present in the tiny 150-micrometer particle from Itokawa. Zega affirmed, “The terrestrial samples did not contain any sodium chloride, so that convinced us the salt in our sample is native to the asteroid Itokawa. We ruled out every possible source of contamination.” The researchers also discovered a vein of plagioclase, a sodium-rich silicate mineral, running through the sample, further indicating the involvement of water in the asteroid’s history.