The solar system was formed in less than 200,000 years

The artistic conception of the dust and gas surrounding a newly formed planetary system. Image courtesy of NASA.

A long time ago – about 4.5 billion years – our sun and our solar system formed in the short span of 200,000 years. This is the conclusion of a group of scientists at Lawrence Livermore National Laboratory (LLNL) after examining the isotopes of the element molybdenum found on meteorites.

The material that makes up the sun and the rest of the solar system comes from the collapse of a large cloud of gas and dust about 4.5 billion years ago. Observing other star systems that formed similarly to ours, astronomers estimate that it probably takes about 1-2 million years for a cloud to collapse and a star to ignite, but this is the first study capable of provide numbers about our solar system.

“Previously, the formation period was not really known for our solar system,” said LLNL cosmochemist Greg Brennecka, lead author of an article in 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 scale all of this down to human lifespan, the formation of the solar system would be comparable to a pregnancy lasting about 12 hours instead of nine months. This was a quick process. “

The oldest dated solids in the solar system are calcium-aluminum rich inclusions (CAI) and these samples provide a direct record of the solar system’s formation. These micrometer-to-centimeter-sized inclusions in meteorites formed in a high-temperature environment (more than 1,300 Kelvin), likely near the young sun. They were then transported outward to the region where the carbonaceous chondrite meteorites (and their parent bodies) formed, where they are found today. Most of the CAI was formed 4.567 billion years ago, in a period between about 40,000 and 200,000 years.

This is where the LLNL team comes into play. The international team measured the isotopic compositions of molybdenum (Mo) and trace elements of a variety of CAIs taken from carbonaceous chondrite meteorites, including Allende, the largest carbonaceous chondrite found on Earth. Because they found that the distinct Mo isotopic compositions of the CAIs cover the full range of material that formed in the protoplanetary disk instead of a small slice, these inclusions must have formed within the cloud collapse period.

Since the observed time span of stellar accretion (1-2 million years) is much longer than the CAIs formed, the team was able to pinpoint which astronomical phase in the formation of the solar system was recorded. from the formation of the CAI and, finally, rapidly the material that makes up the solar system has accumulated.

Former LLNL scientist Thomas Kruijer (now at the Museum für Naturkunde in Berlin) also contributed to this study, as did researchers from the University of Münster, the California Institute of Technology, and the University of California, Santa Cruz.

The work is funded by the research and development program directed by the LLNL laboratory and by NASA.