It decays into the 53Cr isotope in 3.7 million years, so application of the short-lived 53Mn chronometer offers the opportunity to obtain age information of an even finer relative time scale. Meteorites are fragments of solar system bodies that fell to Earth, and the class of primitive meteorites provides a record of processes that formed the solar system 4.5 billion years ago, explained Zinner. One type of meteorite, called carbonaceous chondrite, offers the best example of the chemical composition of the average solar body and, consequently, the most accurate information about the origin of the sun and planets. This process began when the temperature rose on the parent bodies of primitive meteorites and ice crystals melted and reacted with minerals, producing the carbonates studied by Zinner and his colleagues. Studying samples of primitive meteorites indicates when parent bodies formed and what processes shaped them.
Aqueous alteration is one of the most powerful cosmic processes and still is shaping the planets.