A strange waltz around a blue ice giant

Strange things happen in the cold twilight of the outer Solar System. In this faraway region, four giant planets beckon observers on Earth with their tantalizing trove of enchanting, shocking, strange, and wildly wonderful mysteries. The beautiful, blue, banded ice giant Neptune is the most distant giant planet from our Sun, as well as the smallest of the quartet of outer gas worlds. But even by the strange standards of the outer Solar System, certain oddities stand out in this crowd of weirdos. One such outstanding oddity is the strange waltz of escape performed by the innermost duo of Neptune’s icy moons. In November 2019, astronomers announced that the tiny Neptunian moons, Naiad and Thalassathey’re in orbits that bring them just 1,150 miles from each other, but the two moons never get close enough to dance.

Orbital dynamics experts refer to this bizarre performance as an “evasion dance.” The two small moons are close to each other, but nevertheless manage to stay far enough away to avoid a close encounter. This is because naiad the orbit is inclined and perfectly synchronized. Every time this little moon passes the slow motion Thalassathe duo is about 2,200 miles apart.

While this strange ballet of the moons is performed, Naiad it revolves around its parent planet every seven hours. Meanwhile, the Thalassa dance on the outer path lasts seven and a half hours. If an earthling stood on Thalassaand looked in amazement at his strange alien sky, it would seem that naiad the orbit creates a weird and wild zigzag pattern, passing twice from above and then twice from below. This rather strange performance occurs over and over again as Naiad acquires four spans over his partner Thalassa.

Although this distant dance may seem strange, it has a definite purpose. It keeps the orbits of the small moons stable.

“We refer to this repeating pattern as a resonance. There are many different types of ‘dances’ that planets, moons and asteroids can follow, but this one has never been seen before,” said Dr. Marina Brozovic in a NASA statement on November 14, 2019. Press release from the Jet Propulsion Laboratory (JPL). Dr. Brozovic is the lead author of the article describing this research, which was published on November 13, 2019, in the journal icarus.

In the distant domain of the giant planets

In the distant domain of the quartet of giant planets, far from the powerful pull of our Star, the planets themselves are the main sources of gravity. Collectively, the gaseous quartet sports a myriad of mostly icy moons, and some of those moons were born at the same time as their parent planet, never far from their birthplace. In contrast, some of the other moons were caught up later in their planet’s history and then locked into orbits controlled by their parent planets. Some of these many moons circle in the opposite direction of their planet’s direction of rotation, while others swap orbits with one another as if to avoid a catastrophic collision.

The four giant planets in the outer Solar System are Jupiter, Saturn, Uranus, and Neptune. Neptune and Uranus are classified as ice giantswhile Jupiter and Saturn are classified as gas giants. Both ice giants they are covered by thick gaseous atmospheres that are, however, much thinner than those possessed by the much larger giant gas duo. Also, Uranus and Neptune contain larger solid nuclei than Jupiter and Saturn, and both are smaller than the huge gas giants.

Galileo Galilei (1564-1642) detected Neptune on December 28, 1612. Galileo used his primitive “catalage,” one of the first telescopes used for astronomical purposes, to make his discovery of the outermost known giant planet in our Solar System. He re-detected Neptune a second time on January 27, 1613. Unfortunately, on both occasions, Galileo mistook this distant world for a fixed star located near the planet Jupiter. Due to this unfortunate case of mistaken scientific identity, Galileo is generally not credited with the discovery of Neptune.

from NASA traveler 2 spaceship whizzed past the blue-green something larger ice Giant, Uranus, in 1989, sending back to Earth some interesting images of Neptune that revealed a beautiful world with sapphire blue bands. Those early images of Neptune also showed spinning, dot-shaped storms that were eerily similar to hurricanes on Earth. Neptune’s stripes and stripes are different shades of blue and formed as a result of atmospheric methane, not oxygen. Some of Neptune’s storms look like swirling white marshmallows.

traveler 2 also managed to be the first spacecraft to detect Neptune’s great dark spot in 1989. The great dark spot it was an anticyclonic storm extending 19,000 X 6,000 kilometers, and astronomers on Earth immediately noted the resemblance between this distant Neptunian storm and the one on Jupiter. great red spot. However, several years later, on November 2, 1994, the Hubble Space Telescope (HST) did not detect the Great Dark Spot–which had apparently disappeared. Instead, HST discovered a new storm, which was very similar to the one great dark spotin the northern hemisphere of Neptune.

Neptune itself is not visible to the unaided human eye, and it is the only planet in our Solar System that has been discovered by mathematical prediction rather than direct observation. Unexpected changes in Uranus’s orbit led French astronomer Alexis Bouvard (1767-1843) to determine mathematically that Uranus’s orbit was being influenced by the gravitational pull of an undiscovered planet. As a result, Neptune was discovered with a telescope on September 23, 1846 by the German astronomer Johann Galle (1812-1911). Galle discovered Neptune within one degree of the position previously predicted by the French mathematician and astronomer Urbain Le Verrier (1811-1877). Not long after Neptune’s discovery, its largest moon, Triton, was discovered. None of the planet’s remaining known moons were detected telescopically until the 20th century.

Neptune’s distance from our planet makes it appear small in Earth’s sky, making it difficult for astronomers to observe with ground-based telescopes. the space telescope HSTtogether with large telescopes on the ground, recently provided a treasure trove of detailed observations from afar using the technique of adaptive optics. adaptive optics is a method that corrects for distortions resulting from temperature, wind, and mechanical stress by deforming a mirror to compensate for this distortion.

Like the other gas giant planets that inhabit the outer Solar System, Neptune has many moons and a web-like ring system. Neptune’s rings are fragmented and very faint, and are known as arches. Tea arches They were first discovered in 1982, and were later confirmed by the traveler 2 spacecraft.

Neptune has 14 known moons. neso It is the furthest Neptunian moon from its parent planet, and its orbit creates a strange elliptical loop that takes it nearly 46 million miles away from Neptune. neso it takes 27 years to complete a single orbit.

A strange heavenly waltz

Naiad and Thalassa they are very small lunar worlds whose shape has been compared to “Tic Tacs”. Both small moons are only about 60 miles long. As two of Neptune’s seven inner moons, Naiad and Thalassa they are members of a densely populated system that is intricately intertwined with faint Neptune bow rings

How did this strange duo end up so close yet so far? Astronomers propose that the original system of moons was disrupted when Neptune’s powerful gravitational pull caught up with its large moon, Triton. As a result, the inner moons and rings were born from the remnants of debris left behind in the wake of this ancient calamity.

Triton goes around Neptune in the wrong direction. This usually indicates a captured object that didn’t spawn at its current position. Triton may be an unhappy wanderer of the Kuiper belt that it traveled too close to Neptune’s gravitational embrace and thus became a moon of one of the major planets in our Solar System. Tea Kuiper belt it is a region beyond Neptune that hosts a population of objects of different sizes and is considered the home of frozen comet nuclei. In the future, Triton’s orbit will likely decay to the point where it plunges into its adoptive parent planet.

“We suspect that Naiad it was propelled into its inclined orbit by an earlier interaction with one of Neptune’s other inner moons. Only later, after its orbital inclination was established, could it Naiad settle into this unusual resonance with Thalassa,” Dr. Brozovic explained on November 14, 2019 JPL press release.

Dr. Brozovic and her team discovered the strange orbital drama by analyzing observations made by HST. His work also provides the first indication of the internal composition of Neptune’s inner moons. The scientists used the observations to calculate their mass and thus determine their densities, which turned out to be similar to those of water ice.

Dr. Mark Showalter, a planetary astronomer at the SETI Institute in Mountain View, California, and a co-author on the paper, told reporters that “Naiad and Thalassa They’ve probably been locked together in this configuration for a long time, because it makes their orbits more stable. They keep the peace by never getting too close.”