Washington: According to research at the Association of Universities for Research in Astronomy (AURA), researchers have developed a single atmospheric model that matches observations of both planets. The model reveals that excess haze on Uranus builds up in the planet's stagnant, sluggish atmosphere and makes it appear a lighter tone than Neptune Using observations from the Gemini North telescope, the NASA Infrared Telescope Facility, and the Hubble Space Telescope. Neptune and Uranus have much in common -- they have similar masses, sizes, and atmospheric compositions -- yet their appearances are notably different. At visible wavelengths, Neptune has a distinctly bluer colour whereas Uranus is a pale shade of cyan. Astronomers now have an explanation for why the two planets are of different colours. New research suggests that a layer of concentrated haze that exists on both planets is thicker on Uranus than a similar layer on Neptune and 'whitens' Uranus's appearance more than Neptune's. If there were no haze in the atmospheres of Neptune and Uranus, both would appear almost equally blue. This conclusion comes from a model that an international team led by Patrick Irwin, Professor of Planetary Physics at Oxford University, developed to describe aerosol layers in the atmospheres of Neptune and Uranus. Previous investigations of these planets' upper atmospheres had focused on the appearance of the atmosphere at only specific wavelengths. However, this new model, consisting of multiple atmospheric layers, matches observations from both planets across a wide range of wavelengths. The new model also includes haze particles within deeper layers that had previously been thought to contain only clouds of methane and hydrogen sulfide ices."This is the first model to simultaneously fit observations of reflected sunlight from ultraviolet to near-infrared wavelengths," explained Irwin, who is the lead author of a paper presenting this result in the Journal of Geophysical Research: Planets. "It's also the first to explain the difference in visible color between Uranus and Neptune." The team's model consists of three layers of aerosols at different heights. The key layer that affects the colors is the middle layer, which is a layer of haze particles (referred to in the paper as the Aerosol-2 layer) that is thicker on Uranus than on Neptune. The team suspects that, on both planets, methane ice condenses onto the particles in this layer, pulling the particles deeper into the atmosphere in a shower of methane snow. Because Neptune has a more active, turbulent atmosphere than Uranus does, the team believes Neptune's atmosphere is more efficient at churning up methane particles into the haze layer and producing this snow. This removes more of the haze and keeps Neptune's haze layer thinner than it is on Uranus, meaning the blue color of Neptune looks stronger. "We hoped that developing this model would help us understand clouds and hazes in the ice giant atmospheres," commented Mike Wong, an astronomer at the University of California, Berkeley, and a member of the team behind this result. "Explaining the difference in color between Uranus and Neptune was an unexpected bonus!"To create this model, Irwin's team analyzed a set of observations of the planets encompassing ultraviolet, visible, and near-infrared wavelengths (from 0.3 to 2.5 micrometres) taken with the Near-Infrared Integral Field Spectrometer (NIFS) on the Gemini North telescope near the summit of Maunakea in Hawai'i -- which is part of the international Gemini Observatory, a Program of NSF's NOIRLab -- as well as archival data from the NASA Infrared Telescope Facility, also located in Hawai'i, and the NASA/ESA Hubble Space Telescope.The NIFS instrument on Gemini North was particularly important to this result as it is able to provide spectra -- measurements of how bright an object is at different wavelengths -- for every point in its field of view. This provided the team with detailed measurements of how reflective both planets' atmospheres are across both the full disk of the planet and across a range of near-infrared wavelengths. "The Gemini observatories continue to deliver new insights into the nature of our planetary neighbors," said Martin Still, Gemini Program Officer at the National Science Foundation. "In this experiment, Gemini North provided a component within a suite of ground- and space-based facilities critical to the detection and characterization of atmospheric hazes."The model also helps explain the dark spots that are occasionally visible on Neptune and less commonly detected on Uranus. While astronomers were already aware of the presence of dark spots in the atmospheres of both planets, they didn't know which aerosol layer was causing these dark spots or why the aerosols at those layers were less reflective. The team's research sheds light on these questions by showing that a darkening of the deepest layer of their model would produce dark spots similar to those seen on Neptune and perhaps Uranus.—ANI

According to research at the Association of Universities for Research in Astronomy (AURA), researchers have developed a single atmospheric model that matches observations of both planets.

Reasons behind different colors of Uranus, Neptune: Research

California: Jupiter should have more impressive, larger rings than Saturn since it is larger. However, according to a recent study from UC Riverside, Jupiter's enormous moons block this vision from illuminating the night sky.The findings of the research were published in the journal 'Planetary Science'."It's long bothered me why Jupiter doesn't have even more amazing rings that would put Saturn's to shame," said UCR astrophysicist Stephen Kane, who led the research."If Jupiter did have them, they'd appear even brighter to us, because the planet is so much closer than Saturn." Kane also had questions about whether Jupiter once had fantastic rings and lost them. It is possible for ring structures to be temporary. To understand the reason Jupiter currently looks the way it does, Kane and his graduate student Zhexing Li ran a dynamic computer simulation accounting for the orbits of Jupiter's four main moons, as well as the orbit of the planet itself, and information about the time it takes for rings to form. Their results are now online, soon to be published in the Planetary Science journal.Saturn's rings are largely made of ice, some of which may have come from comets, which are also largely made of ice. If moons are massive enough, their gravity can toss the ice out of a planet's orbit, or change the orbit of the ice enough so that it collides with the moons. "We found that the Galilean moons of Jupiter, one of which is the largest moon in our solar system, would very quickly destroy any large rings that might form," Kane said. As a result, it is unlikely that Jupiter had large rings at any point in its past. "Massive planets form massive moons, which prevents them from having substantial rings," Kane said. All four giant planets in our solar system -- Saturn, Neptune, Uranus and also Jupiter -- do in fact have rings. However, both Neptune and Jupiter's rings are so flimsy they're difficult to view with traditional stargazing instruments.Coincidentally, some of the recent images from the newly commissioned James Webb Space Telescope included pictures of Jupiter, in which the faint rings are visible."We didn't know these ephemeral rings existed until the Voyager spacecraft went past because we couldn't see them," Kane said.Uranus has rings that aren't as large but are more substantial than Saturn's. Going forward, Kane intends to run simulations of the conditions on Uranus to see what the life of that planet's rings might be. Some astronomers believe Uranus is tipped over on its side as the result of a collision the planet had with another celestial body. Its rings could be the remains of that impact.Beyond their beauty, rings help astronomers understand the history of a planet because they offer evidence of collisions with moons or comets that may have happened in the past. The shape and size of the rings, as well as the composition of the material, offer an indication of the type of event that formed them. "For us astronomers, they are the blood spatter on the walls of a crime scene. When we look at the rings of giant planets, it's evidence something catastrophic happened to put that material there," Kane said.&nbsp;—ANI

Jupiter should have more impressive, larger rings than Saturn since it is larger. However, according to a recent study from UC Riverside, Jupiter's enormous moons block this vision from illuminating the night sky.

Study: Why Jupiter Lacks Ring System Like Saturn

Washington: One or two of Uranus' 27 moons -- Ariel and/or Miranda -- likely have oceans beneath their icy surfaces and are actively spewing material into the space environment, according to a study by NASA.
Previously, Jupiter, Saturn and Neptune were found as hosts to at least one icy moon that's pumping particles into its planetary system.
In the study led by the Johns Hopkins Applied Physics Laboratory (APL) in Maryland, US, researchers reanalysed nearly 40-year-old energetic particle and magnetic field data taken by NASA's Voyager 2 spacecraft -- the only spacecraft so far to have gone to Uranus.
They found a trapped population of energetic particles the spacecraft had observed while departing Uranus -- the turquoise, tilted oddball of the solar system. "What was interesting was that these particles were so extremely confined near Uranus' magnetic equator," said lead author Ian Cohen, a space scientist at APL.
Magnetic waves within the system would normally cause them to spread out in latitude, he explained, but these particles were all cramped near the equator between the moons Ariel and Miranda.
Scientists originally attributed these features to Voyager 2's possibly having flown through a chance stream of plasma being "injected" from the distant tail of the planet's magnetosphere. But that explanation doesn't hold, Cohen said. "An injection would normally have a much broader spread of particles than what was observed."
The team suspects the particles arise from Ariel and/or Miranda through either a vapour plume similar to that seen on Enceladus or through sputtering -- a process where high-energy particles hit a surface, ejecting other particles into space.
Yet scientists have already suspected Uranus' five largest moons -- Ariel and Miranda included -- may have subsurface oceans. Voyager 2 images of both moons show physical signs of geologic resurfacing, including possible eruptions of water that froze on the surface.
"The data are consistent with the very exciting potential of there being an active ocean moon there," Cohen said. "We can always do more comprehensive modelling, but until we have new data, the conclusion will always be limited."
The findings, recently accepted for publication in the journal Geophysical Research Letters, were also presented at the annual Lunar and Planetary Science Conference in the US. —IANS

One or two of Uranus' 27 moons -- Ariel and/or Miranda -- likely have oceans beneath their icy surfaces and are actively spewing material into the space environment, according to a study by NASA.

Two of Uranus' Moons May Have Active Oceans: NASA Study

Washington: National Aeronautics and Space Administration (NASA) has announced that their scientists have evidence of a polar cyclone on Uranus. The announcement was made after examining radio waves emitted from the ice giant. The findings have revealed broad truth about all planets with substantial atmospheres in the solar system. Scientists have long known that Uranus' south pole has a swirling feature. "In a first, NASA scientists have strong evidence of a polar cyclone on Uranus. By examining radio waves emitted from the ice giant, they detected the phenomenon at the planet's north pole. The findings confirm a broad truth about all planets with substantial atmospheres in our solar system: Whether the planets are composed mainly of rock or gas, their atmospheres show signs of a swirling vortex at the poles," NASA said in the press release.  NASA's Voyager 2 imaging of methane cloud tops showed winds at the polar center spinning faster than over the rest of the pole. Voyager's infrared measurements observed no temperature changes. However, the new findings published in Geophysical Research Letters have revealed it. "Using huge radio antenna dishes of the Very Large Array in New Mexico, they peered below the ice giant's clouds, determining that the circulating air at the north pole seems to be warmer and drier - the hallmarks of a strong cyclone. Collected in 2015, 2021, and 2022, the observations went deeper into Uranus' atmosphere than any before," NASA said in the press release. "These observations tell us a lot more about the story of Uranus. It's a much more dynamic world than you might think," lead author Alex Akins of NASA's Jet Propulsion Laboratory in Southern California in a press release said, adding, "It isn't just a plain blue ball of gas. There's a lot happening under the hood." Uranus is showing off more these days due to the planet's position in orbit. It's a long haul around the solar system for Uranus, taking 84 years to complete a full lap and for the past few decades, the poles weren't pointed toward Earth. Since about 2015, scientists have had a better view and have been able to look deeper into the polar atmosphere. (ANI)

 National Aeronautics and Space Administration (NASA) has announced that their scientists have evidence of a polar cyclone on Uranus

NASA scientists make observation of a polar cyclone on Uranus

Washington: While Neptune is fondly known for being a rich blue and Uranus green, a new study revealed that the two ice giants are actually far closer in colour than typically thought. Despite the commonly-held belief that Neptune is a deep azure and Uranus has a pale cyan appearance, the study, published in the Monthly Notices of the Royal Astronomical Society, showed that both worlds are in fact a similar shade of greenish blue. Astronomers have long known that most modern images of the two planets do not accurately reflect their true colours. The misconception arose because images captured of both planets during the 20th century -- including by NASA’s Voyager 2 mission, the only spacecraft to fly past these worlds – recorded images in separate colours. The single-colour images were later recombined to create composite colour images, which were not always accurately balanced to achieve a "true" colour image, and – particularly in the case of Neptune – were often made "too blue". In addition, the early Neptune images from Voyager 2 were strongly contrast enhanced to better reveal the clouds, bands, and winds that shape our modern perspective of Neptune. "Although the familiar Voyager 2 images of Uranus were published in a form closer to ‘true’ colour, those of Neptune were, in fact, stretched and enhanced, and therefore made artificially too blue," said Professor Patrick Irwin from the University of Oxford. "Even though the artificially-saturated colour was known at the time amongst planetary scientists -- and the images were released with captions explaining it -- that distinction had become lost over time. "Applying our model to the original data, we have been able to reconstitute the most accurate representation yet of the colour of both Neptune and Uranus," he said. In the new study, the researchers used data from Hubble Space Telescope’s Space Telescope Imaging Spectrograph (STIS) and the Multi Unit Spectroscopic Explorer (MUSE) on the European Southern Observatory’s Very Large Telescope. In both instruments, each pixel is a continuous spectrum of colours. This means that STIS and MUSE observations can be unambiguously processed to determine the true apparent colour of Uranus and Neptune. The researchers used these data to re-balance the composite colour images recorded by the Voyager 2 camera, and also by the Hubble Space Telescope’s Wide Field Camera 3 (WFC3). This revealed that Uranus and Neptune are actually a rather similar shade of greenish blue. The main difference is that Neptune has a slight hint of additional blue, which the model reveals to be due to a thinner haze layer on that planet. —IANS While Neptune is fondly known for being a rich blue and Uranus green, a new study revealed that the two ice giants are actually far closer in colour than typically thought. Despite the commonly-held belief that Neptune is a deep azure and Uranus has a pale cyan appearance, the study, published in the Monthly Notices of the Royal Astronomical Society, showed that both worlds are in fact a similar shade of greenish blue. Astronomers have long known that most modern images of the two planets do not accurately reflect their true colours. The misconception arose because images captured of both planets during the 20th century -- including by NASA’s Voyager 2 mission, the only spacecraft to fly past these worlds – recorded images in separate colours. The single-colour images were later recombined to create composite colour images, which were not always accurately balanced to achieve a "true" colour image, and – particularly in the case of Neptune – were often made "too blue". In addition, the early Neptune images from Voyager 2 were strongly contrast enhanced to better reveal the clouds, bands, and winds that shape our modern perspective of Neptune. "Although the familiar Voyager 2 images of Uranus were published in a form closer to ‘true’ colour, those of Neptune were, in fact, stretched and enhanced, and therefore made artificially too blue," said Professor Patrick Irwin from the University of Oxford. "Even though the artificially-saturated colour was known at the time amongst planetary scientists -- and the images were released with captions explaining it -- that distinction had become lost over time. "Applying our model to the original data, we have been able to reconstitute the most accurate representation yet of the colour of both Neptune and Uranus," he said. In the new study, the researchers used data from Hubble Space Telescope’s Space Telescope Imaging Spectrograph (STIS) and the Multi Unit Spectroscopic Explorer (MUSE) on the European Southern Observatory’s Very Large Telescope. In both instruments, each pixel is a continuous spectrum of colours. This means that STIS and MUSE observations can be unambiguously processed to determine the true apparent colour of Uranus and Neptune. The researchers used these data to re-balance the composite colour images recorded by the Voyager 2 camera, and also by the Hubble Space Telescope’s Wide Field Camera 3 (WFC3). This revealed that Uranus and Neptune are actually a rather similar shade of greenish blue. The main difference is that Neptune has a slight hint of additional blue, which the model reveals to be due to a thinner haze layer on that planet. —IANS

While Neptune is fondly known for being a rich blue and Uranus green, a new study revealed that the two ice giants are actually far closer

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Reasons behind different colors of Uranus, Neptune: Research

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Reasons behind different colors of Uranus, Neptune: Research

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