NASA's Juno Spacecraft. But Juneau is not just a member of the interplanetary paparazzi, it is a . After making accurate measurements of Jupiter's gravitational field, the spacecraft discovered that the planet's nucleus was not as tight as expected.
Now scientists have suggested an almost apocalyptic reason for this: a "planetary embryo" with 1
A study published Wednesday in the journal Nature describes in detail a number of simulations demonstrating how a planetary embryo can have the uneven distribution of heavy metals seen in Jupiter's gaseous shell today. Jupiter consists mainly of hydrogen and helium gases that move around a dense nucleus. Scientists believed that heavy metals should be confined to a dense core, but the Juno mission revealed that the metals are actually scattered farther from the nucleus, which makes it thinner.
"Jupiter's interior models, based on Juno data, show that Jupiter has a fuzzy nucleus that extends to nearly half of its radius, which no one ever imagined," says Shangfei Liu, lead author of the study and an astronomer at Sun Yatsen University in China.
How can this happen? The simulations of the research team suggest that young Jupiter has had a tremendous impact during its formative years, leading to this strange, unexpected spread.
Although the collision sounds violent, it is almost as if young Jupiter had swallowed a planetary embryo. "A planetary embryo is still a protoplanet, formed mainly by rock and ice from the solar nebula," Liu explains. Simulations show that the core of the protoplanet would have to collide with Jupiter's core in order to throw the heavy elements and mix them throughout the envelope. The models indicate that the impact would lead to an internal structure discovered by NASA's Juneau and through the distribution of heavy elements.
Other simulations show that if a smaller planet just jumps over Jupiter, the collision will not have the power to redistribute heavy metals throughout the gaseous shell (although this would still be bad news for the baby planet).
These models also provide an explanation for some of the phenomena observed in a number of readily detectable exoplanets, planets located outside our solar system. A number of these planets, known as "hot Jupiters", are super dense, arranged with heavy elements and orbit very close to their star. They are also prone to gigantic impacts. Researchers suggest that their model can explain why there are so many heavy metals in these hot Jupiters as they break down from planetary embryos as they form.
Can a series of small events, rather than a huge impact, lead to the Jupiter we see today? Researchers say it needs more study.
The work provides further evidence of the turbulent environment of the early solar system. Previous studies have indicated that massive impacts have shaped our Moon and the Earth itself. New research even suggests that Saturn may have experienced such an impactful event during its formation and another NASA probe, Cassini,.
"There are studies using Cassini's data (especially during his grand finale) to model Saturn's interior," says Liu. "But Juno is designed to measure Jupiter's gravitational field, so the data is much better and the models are more reliable. But Saturn's interior is definitely worth looking into in the future."
As for Juno? Researcher Jovian has been traveling around Jupiter since 2016, and recentlyso we can look forward to more revelations.
Originally posted on Aug 14, 10:15 AM
Updated on August 15 at 3:57 pm: Adds Comments by Shangfei Liu.