A new study from an international team of astronomers has dated Jupiter for the first time, and their findings suggest that the Gas Giant is the oldest planet in the solar system.
Dating a celestial object isn't too difficult, so long as you have a sample of it. The Earth is about 4.543 billion years old, for instance. Jupiter, meanwhile is about 4.599 billion years old, making it 56 million years older than the Earth.
But no human has ever set foot on Jupiter, nor has any spacecraft. This forced the scientists to think of a different technique for establishing the monster planet's birthday. "We do not have any samples from Jupiter (in contrast to other bodies like the Earth, Mars, the moon and asteroids)," said study lead Thomas Kruijer. "In our study, we use isotope signatures of meteorites (which are derived from asteroids) to infer Jupiter's age.
They discovered two iron meteorites that formed in the early universe, each from different nebular clouds. One formed about 4.599 billion years ago, the other 4.596 billion years ago. "Our measurements show that the growth of Jupiter can be dated using the distinct genetic heritage and formation times of meteorites," Kruijer said.
Assuming that it's accurate, this dating will be a valuable tool in our understanding of how the early solar system formed. For instance, isotope analysis found that Jupiter's solid core formed with the first nebular cloud, only 1 million years after the start of the solar system. The core accreted gas quickly, preventing large amounts of material from slipping into the inner solar system — hence why Mercury, Venus, Earth, and Mars are all small planets and our solar system lacks large, rocky super-Earths.
Source:https://sputniknews.com/science/201706131054602259-jupiter-oldest-planet-solar-system/
Journal article:http://m.pnas.org/content/early/2017/06/06/1704461114
Photo credit: NASA
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