Then the shifting gas giants scattered those bodies everywhere. In all the early chaos, a thousand Plutos may have formed in the distant part of the solar system where Neptune orbits today, including a nascent Ceres. Nice Model In the Nice model, all four gas giants do the rearranging.NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute/Lunar and Planetary Institute The two theories aren’t mutually exclusive Sean Raymond, one of the theorists behind the Grand Tack, says it was designed to work with the Nice model. The other, the Nice model, suggests the four gas giants (Jupiter through Neptune) initially had tiny, tight orbits, which eventually spread out slowly to what we see today. One, the Grand Tack hypothesis, suggests that Jupiter and Saturn initially ducked inward to the inner solar system, before gravitational imbalances sent them back to their current orbits far from the sun. Two models, both devised in the 2000s, best fit the orbital data. The early solar system was a chaotic place, and astronomers now suspect many of the planets may have wandered before settling into today’s orbits. In the Grand Tack model, Jupiter’s and Saturn’s migrating orbits pushed Pluto outward and Ceres inward.NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute/Lunar and Planetary Institute Grand Tack ModelTwo early solar system models could explain Ceres’ and Pluto’s current locations. It turns out that might actually be the case, with Ceres originally starting out nearer to Pluto, before getting shoved around by the bigger planets. “If you took a Pluto-like body and put it in the asteroid belt, it would probably look a lot like Ceres,” says astronomer Will Grundy, a co-investigator for New Horizons. It’s thanks to those missions that we have all this new data in the first place. One more commonality: NASA spacecraft visited both worlds in 2015 - New Horizons flew past Pluto and Dawn began orbiting Ceres. Their differing adult features reflect their adopted environments. ![]() In fact, astronomers are beginning to consider them twins, albeit fraternal, born in the same place at the same time but separated almost immediately after birth. ![]() Large depressions mar the surface of each, and both feature icy volcanoes possibly powered by liquid beneath the surface. New traces of ammonia on Ceres hint at a much closer relationship between the pair. ![]() The worlds are so dissimilar that planetary scientist Steve Desch says he is one of only a handful of researchers familiar with both.īut look a little closer, and it turns out the dwarf planets aren’t all that different. A thin, hazy atmosphere hangs over Pluto, while astronomers have seen only faint traces of gas above Ceres. A mixture of rock and water ice dominates Ceres’ landscape, while methane and nitrogen ices cover Pluto. Nestled in the asteroid belt between Mars and Jupiter, Ceres is a tiny loner, while Pluto - in the Kuiper Belt at the edge of the solar system - is nearly three times as big and hosts a handful of moons. Ceres and Pluto don’t seem to have much in common.
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