What’s cool about Pluto? Get a quick peek at the latest science in this daily update from NASA’s New Horizons mission, on track for a flight past Pluto on July 14, 2015.
How does a planet so small and so far from the Sun have an atmosphere? This is Pluto in a Minute.
Pluto’s orbit actually crosses Neptune’s, so for about two decades of every 248 Earth year orbit Pluto makes around the Sun, it’s inside the orbit of Neptune.
It turns out Neptune has a huge effect on Pluto’s orbit, and the two bodies are actually in resonance with one another: for every two orbits Pluto makes around the Sun, Pluto makes three. And scientists think Neptune is actually the reason Pluto is where it is.
One dynamic model of the solar system presented in the 1990s suggested that the planet actually formed closer to the Sun than they are now. It’s possible under this model that Pluto formed at around 30 AU.
In the mid-2000s, another model was presented called the Nice model suggested that Pluto could have formed as close (to the Sun) as 15 AU. With all these huge gas giants orbiting so closely together, their gravity eventually threw this system into chaos. The planets’ orbits were flung further out from the Sun and all the small bodies were also flung further out. At some point, Pluto and Neptune became locked together in this resonance.
So the question is: If Pluto formed closer to the Sun, how close was it? The data from New Horizons will doubtlessly shed some light on this question, but in the meantime if you want to know more about Pluto be sure to check out the New Horizons websites and tweet your questions using the hashtag #PlutoFlyBy. And of course, come back tomorrow for more Pluto in a Minute.
www.nasa.gov/newhorizons
pluto.jhuapl.edu
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