A team of scientists from the Lawrence Livermore National Laboratory (LLNL) in California (USA) has concluded, after observing the isotopes in molybdenum found in meteorites, that our solar system formed approximately 4.5 billion years ago, in just a few 200,000 years, a very short period of time at astronomical levels.
Among the molybdenum isotopes present in carbonaceous chondrite meteorites and dated by scientists are also those of the Allende meteorite, which fell to Earth in 1969 in Chihuahua, Mexico (it is the largest carbonaceous chondrite ever found on our planet ). Analysis of moly isotopes determined that they were created between 40,000 and 200,000 years ago (just like different layers of clothing are dated on Earth), meaning that our solar system would have formed during that same time period.
Because they found that the different Molybdenum isotopic compositions of the calcium and aluminum-rich inclusions (CAI) covered the entire range of material that formed in the protoplanetary disk rather than just a small portion, these inclusions must have formed within the time lapse of the collapse of the clouds. Most CAIs were formed 4.567 million years ago, over a period of approximately 40,000 to 200,000 years.
A surprising number
The creation of a whole solar system in less than 200,000 years is something quite remarkable, since before it was thought that it would have taken much longer; some experts even estimated that this phase could have developed between one and two million years. Apparently, nothing could be further from the truth. This period of time is significantly shorter than expected.
“Previously, we didn’t really know the formative period of our solar system,” said LLNL cosmochemist Greg Brennecka, lead author of the paper published in the journal Science. “This work shows that this collapse, which led to the formation of the solar system, happened very quickly, in less than 200,000 years.” If we equate it with the development time of a human pregnancy, it is as if the gestation had lasted only 12 hours instead of nine months. “This was a quick process,” says Brennecka.
Thus, our solar system was formed about 4.5 billion years ago from the collapse of a dense cloud of interstellar gas and dust.
How many new secrets will our solar system hide? It is clear that we still have much to discover … For example, why is the configuration of the planets in our solar system so atypical?
Former LLNL scientist Thomas Kruijer (now at the Museum für Naturkunde in Berlin, Germany) also contributed to this study, as well as researchers from the University of Münster, the California Institute of Technology, and the University of California, Santa Cruz.
The work is funded by the LLNL and NASA Laboratory Driven Research and Development program.
Reference: Gregory A. Brennecka et al. Astronomical context of Solar System formation from molybdenum isotopes in meteorite inclusions, Science (2020). DOI: 10.1126 / science.aaz8482
