An international team of researchers has discovered evidence that suggests Jupiter is the oldest planet in the solar system.
The Early Years Of The Solar System
To determine the age of Jupiter, the researchers examined the chemical elements— tungsten and molybdenum in particular— found in meteorites. They found that the meteorites were made up of two nebular reservoirs that coexisted but were separated sometime between 1 million and 4 million years after the formation of the solar system.
Of course, that leads to the question of when the solar system formed. The answer varies depending on who is counting, but one common starting point is when celestial bodies began to form around the sun. This generally held to have occurred about 4.5 billion years ago.
The research team concluded that the most probable explanation for the separation of these two nebular reservoirs was the formation that prevented the two bodies from exchanging material.
The Oldest Planet In The Solar System
"Jupiter is the oldest planet of the solar system, and its solid core formed well before the solar nebula gas dissipated, consistent with the core accretion model for giant planet formation," said Thomas Kruijer, who served as the lead author on the recently released study published in PNAS regarding Jupiter's origins.
Unlike Mars and the moon, researchers do not have access to any material from Jupiter that could be used to determine the planet's age. Instead, they relied on an analysis of isotope signatures found in asteroids to determine the age of Jupiter.
The team's research found that Jupiter's core formed about 1 million years after the formation of the solar system. From that point, Jupiter ballooned to massive size. Within a million years, it was 20 times larger than the Earth and continued to grow over the course of the next several million years.
Jupiter's rapid growth may also have prevented the formation of a super-Earth, which is an Earth-like planet with much larger mass. Obviously, such planets do not exist within our solar system, but similar planets have been found in other solar systems.
Beyond being the solar system's oldest planet, Jupiter's large size has played an important role in the early years of the solar system, and understanding the origins of Jupiter is an important step toward a better understanding of our solar system as a whole.
Scientists are hopeful that this model can be applied to other planets in our solar system such as Jupiter's fellow gas giant Saturn.