There is a lot One of the interesting things about Uranus. Its season lasts all day, is the second least dense planet, and has a cluster of 27 moons.
But perhaps the most puzzling fact about Uranus is that it’s the only planet on its side — at least relative to its orbital plane.
The most common suggestion as to why the planet is tilted 98 degrees on its axis is that it had a series of large impacts early in the formation of the solar system.
However, new studies from a team at the Sorbonne suggest a possible alternative explanation – Uranus used to have another, larger moon pulling it to its side and then affecting the planet itself.
defects in the model
Recently a wave of research is taking place on the orbital mechanics of gas giants. This wave helped explain a series of flaws in our current model of what happened to Uranus. The most obvious flaw is highlighted by the similarity between Uranus and one of its neighbors – Neptune.
Neptune’s axial tilt is only 30 degrees (still a lot by planetary standards) but not near that of Uranus. However, both planets have similar rotation rates. Impacts large enough to hit an entire planet on its side will also have a huge impact on its rate of rotation.
So it’s not likely that small, random effects could have caused one planet to warm by about 70 degrees than the other without affecting its rotation rates.
Similar rotation rates indicate “smoother” processes that occurred over eons but greatly influenced the properties of the two gas giants.
The real reason for the tilt?
Scientists have already hypothesized the “Great Migration” of the outer planets through the inner Solar System and a cloud of early planets, which is likely the cause of events such as the Late Heavy Bombardment, which is responsible for many of the craters visible on our planet. the moon.
This got the researchers thinking – the axial tilt in gas giants is usually established as early as their formative years. The relatively small axial tilts of Jupiter, Saturn, and Neptune can be explained by phenomena that occurred one time after the planets were fully formed. However, the higher inclination of Uranus is different.
Scientists hypothesize that it may have occurred in two phases. At first, a relatively large moon, about 0.3 percent the size of the planet itself, got stuck in an echo loop with the host planet and slowly pulled the planet onto its side.
Due to the complex orbital mechanics, which are well explained in a recent paper the authors published on the arXiv preprint server, a sufficiently large moon could interact with its parent planet’s gravitational force in a way that would cause it to gravitate toward its side.
However, the second stage is the more interesting of the two, at least from the point of view of the astronomical catastrophe. Currently, Uranus has 27 known satellites, none of which fit the description required to create such orbital resonances. So where did you go? Most likely, it crashed into the planet itself after its orbital repulsion destabilized its orbit.
There are still some issues with this two-stage theory as well – for example, would the current crop of Uranus’ moons have survived a giant moon making its way toward its ultimate destruction?
But based on models run by the Sorbonne team, there appears to be a plausible physical scenario where Uranus ends up tilting at the correct rates of rotation and orbit, and an impact on the planet destroys the companion satellite that caused that tilt.
It’s a great idea that requires further study. Unfortunately, it will likely be a long time before we find any other physical evidence that might indicate whether or not the theory is correct.
But at the very least, it’s interesting to imagine that Uranus is slowly being pulled from one of its moons over billions of years, only to eventually be bumped into by that moon. Such a dramatic date will make the planet more interesting.
This article was originally published the universe today by Andy Thomaswick. Read the original article here.
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