Scientists Determine the Oldest Planet in the Solar System

Jupiter is not only the biggest planet in our solar system, but new research confirms it's also the oldest. How do we know? Researchers found some tell-tale signs in meteorites.

Two Kinds of Meteorites

Study co-author Thomas S. Kruijer says this "is the first time that we can say something about Jupiter based on measurements done in the lab." Until now, similar work was done based on computer models.

Kruijer and his colleagues measured meteorite samples to learn about Jupiter. They found there are two different categories of meteorites. Starting about one million years after the solar system was born, something blocked the two groups from moving back and forth. This obstruction lasted until the solar system was 3-to-4 million years old.

Researchers believe Jupiter is that culprit, since it formed during that time period.

"The team showed through isotope analyses of meteorites that Jupiter's solid core formed within only about 1 million years after the start of the solar system history, making it the oldest planet," according to a Lawrence Livermore National Laboratory press release. Kruijer said the "genetic heritage and formation times of meteorites" were the clues.

They also report that within its first million years, Jupiter grew to 20 times the mass of Earth. Jupiter continued to grow, eventually moving closer to the sun and allowing all those meteorites to get back together.

Today, if you put all of the other planets in the solar system together, Jupiter would still have 2.5 times as much mass, according to Universe Today.

More to Uncover

"Knowing the age of Jupiter... is key for understanding how the Solar System evolved toward its present-day architecture," the researchers wrote.

According to NASA, the solar system as a whole is around 4.6 billion years old. Scientists believe the gas giants, including Jupiter and Saturn, formed first. Then came the ice giants, including Uranus and Neptune, followed by the rocky planets. Those terrestrial planets include Earth, Mercury, Venus and Mars.

How Long Does It Take to Get to Jupiter?

Key Facts In This Video

  1. Jupiter's moons Europa, Callisto, and Ganymede might contain liquid water under their icy shells. 00:30

  2. The first spacecraft to reach Jupiter was NASA's Pioneer 10. It took 640 days to get there. 01:33

  3. The only craft to actually orbit Jupiter was NASA's Galileo spacecraft. Its journey was 2,242 days. 02:41

Written by Haley Otman July 6, 2017

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