There may be some hidden oceans lurking around Uranus.
New evidence indicates that one or two gas giants 27 known moons It may harbor liquid oceans beneath its crustal outer surface of rock and ice. Possible culprits for seeding space around Uranus with plasma are Miranda and Ariel, one or both of which may explode with ocean plumes.
The data, which came from the Voyager 2 mission that flew past the planet on its way into outer space nearly 40 years ago — the only spacecraft to ever do so — makes an excellent case for sending another probe to Uranus.
“We have demonstrated this case for a few years now that measurements of energetic particles and the electromagnetic field are important not only for understanding the space environment but also for contributing to larger planetary science investigations,” He says Astronomer Ian Cohen of the Johns Hopkins Applied Physics Laboratory.
“It turns out that this can be the case for data older than I am. It just goes to show how important it is to go into a system and explore it first-hand.”
Cohen and his team presented their findings on March 16 in the journal Fifty-fourth Congress of Lunar and Planetary SciencesA paper describing it has been accepted for publication in Geophysical Research Letters.
When Voyager 2 made its flyby of Uranus in 1986, it was Low energy charged particle instrument Pick up something weird: charged particles which appears to be trapped specific areas of the magnetosphere of Uranus. They should have spread out, but they remained confined to the equator, near the orbits of Miranda and Ariel.
on time, Scientists believe That the odd profile was indicative of the injection of energetic electrons from a source such as a Storm in the magnetic field of Uranus. But upon taking a closer look, Cohen and his colleagues found that the electrons did not exhibit the properties expected from sub-injection.
This opened up a huge can of worms, because scientists are now back at square one, trying to understand where the electrons came from. Of particular interest, they said, was the angle of inclination of the electrons: the angle of the velocity vector with respect to the magnetic field.
In order to maintain the pitch angle observed by Voyager 2, a constant source of electrons would be needed, significant enough to overcome the scattering and losses that would occur due to plasma waves in the planets magnetosphere.
Without a source of this kind, in the right place and at the right angle, the team determined through modeling, the pitch-angle distribution of electrons would become uniform in just a matter of hours.
Digging deeper into the Voyager 2 data, the team searched for just such a source. Their modeling showed a clear, undeniable maxima in the space between Miranda and Ariel, suggesting a source of energetic ions in that region.
As for what could generate these ions… Well, in the 37 years since Voyager 2 visited Uranus, scientists have made some progress in that regard. Voyager 2 made a similar discovery in space around Saturn, discovering many years later in Cassini data that icy geysers were being generated on what we now know to be an ocean moon, Enceladus. Another similar discovery led us to Jupiter’s moon Europa.
“It is not uncommon for measurements of energetic particles to be groundbreaking for ocean world discovery,” says Cohen.
As for either of the moons — Miranda, the smallest of Uranus’ five large moons, or Ariel, the brightest — that’s kind of a 50-50 at this point. It could be either. or both. Both moons show signs of a relatively recent geological appearance, which could be consistent with the eruption of liquid material from within.
But, so far, we only have one data set. Planetary scientists have been increasingly calling for a mission dedicated to Uranus, possibly with Neptune. The planet has so many strange quirks that learning more about it can only be a truly exciting and rewarding experience.
The prospect of wet moons is just the icing on the smelly cake.
“The data is consistent with the very exciting potential for an active ocean moon out there,” says Cohen. “We can always do more extensive modeling, but until we get new data, the result will always be limited.”
The search was presented in Fifty-fourth Congress of Lunar and Planetary SciencesAnd it was accepted for publication in Geophysical Research Letters.
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