FYFD

Tag: Jupiter

  • Jovian Auroras

    Jovian Auroras

    Like Earth, Jupiter is home to polar auroras that light the sky as charged particles interact with the planet’s magnetosphere. A recent paper identifies interesting features in the aurora that appear similar to expanding vortex rings (see inset below). Although the researchers cannot yet identify the origin of the rings, they hypothesize that the process begins at the far edges of Jupiter’s magnetosphere where it interacts with the incoming solar wind. One theory posits that shear flows and Kelvin-Helmholtz instabilities where the magnetosphere and solar wind meet drive the phenomenon. (Image credit: Jupiter – NASA, ESA, and J. Nichols, aurora features – NASA/SWRI/JPL-Caltech/SwRI/V. Hue/G. R. Gladstone/B. Bonfond; research credit: V. Hue et al.; via Gizmodo)

    Diagram showing an inset of Jupiter's northern aurora, with further insets showing the expanding ring features.
  • Jupiter in Infrared

    Jupiter in Infrared

    This stunning new image of Jupiter in infrared is part of a data set combining measurements from ground- and space-based observatories. The glowing Jovian orb seen here is a composite of some of the sharpest images captured by the Gemini North Telescope’s Near-Infrared Imager from its perch on Mauna Kea. The brightest areas correspond to warmer temperatures over thinner, hazier clouds, whereas the dark areas mark towering, thick clouds.

    The ground-based images — and observations from Hubble — were timed to coincide with passes from the Juno spacecraft. This combination of infrared, visible light, and radio wave observations gives scientists an unprecedented look at Jovian atmospheric processes. It revealed, for example, that lightning measured by Juno deep inside Jupiter’s atmosphere corresponded to convective storm cores visible to the other imagers. The combination of observations allowed the researchers to reconstruct the structure of these Jovian storms in a way that no single instrument could reveal. No doubt planetary scientists will learn lots more about Jovian convection from the data set. (Image credit: Jupiter – International Gemini Observatory/NOIRLab/NSF/AURA, M.H. Wong (UC Berkeley)/Gizmodo, illustration – NASA, ESA, M.H. Wong (UC Berkeley), and A. James and M.W. Carruthers (STScI); research credit: M. Wong et al.; via Gizmodo)

  • Jovian Vortices

    Jovian Vortices

    Jupiter continues to mesmerize in the images from JunoCam. With enhanced contrast, the planet’s eddies look like swirls you could just lean forward and fall into. The complexity of the Jovian atmosphere’s mixing is just astounding. It’s like an ever-changing Impressionist painting brought to life. Check out full-size versions of these stunning images here and here. (Image credit: NASA/JPL-Caltech/SwRI/MSSS/Kevin M. Gill, 1, 2; via Planetary Society; submitted by jpshoer)

  • Galileo’s Descent

    Galileo’s Descent

    In December 1995, the Galileo probe made its dramatic descent into Jupiter’s atmosphere at a velocity of more than 47 km/s. In 30 seconds, it decelerated from Mach 50 to Mach 1, undergoing incredible heating as it did so. Anytime an object moves through a fluid faster than the local speed of sound, it creates a leading shock wave that compresses the fluid, heats it, and redirects it around the object. The faster the speed, the hotter the fluid will be after passing through the shock wave. 

    Above about five times the speed of sound, the heating effect is so strong that it’s able to rip molecules apart, creating a chemically reactive mixture that will ablate away material from the object. For this reason, Galileo and other planetary entry vehicles carry heat shields made to sacrifice themselves while protecting the cargo and (in some cases) crew onboard. Data from Galileo showed that, although the heat shield survived the brunt of its descent, it experienced worse conditions than expected. Near the heat shield’s shoulder, almost all of its material ablated away. 

    Scientists continue to study Galileo’s descent even now, using it to test and inform their models of the flow and chemistry that occurs at these hypersonic speeds. The better we can understand and predict these flows, the better our designs will become. Mass that’s currently spent on overly-conservative heat shields can instead go toward additional instruments or supplies. (Image credit: Chop Shop Studio; research credit: L. Santos Fernandes et al.; via AIP)

  • Understanding Jupiter

    Understanding Jupiter

    The swirling clouds of Jupiter hide a complicated and mysterious interior. For decades, scientists have worked to puzzle out the inner dynamics of Jupiter’s atmosphere and what could be going on inside it to generate the flows we see visibly. Near Jupiter’s equator, we see strong jets that flow either east or west, depending on their latitude; this creates the stunning cloud bands we’re used to seeing on the planet. Toward the poles, though, things look more like what we see above – swirling but unbanded.

    Through theory, experiments, and simulations, scientists have tried to work out exactly what ingredients are necessary to make Jupiter look this way, but it’s pretty tough to recreate the conditions simply because Jupiter is so extreme. You need a lot of rotation, a lot of turbulence, and a way to stretch that turbulence if you want to imitate Jupiter. There’s been progress recently, though, and it suggests that the jets we see on Jupiter are far more than skin-deep. Instead, they likely stretch deep into the Jovian atmosphere at the equator and ride somewhat shallower toward the poles. (Image credit: NASA JPL; research credit: S. Cabanes et al.)

  • Forming Europa’s Bands

    Forming Europa’s Bands

    Jupiter’s icy moons, Europa and Ganymede, are home to subsurface oceans. These moons also experience strong tidal forces from their parent planet and sibling moons that squeeze and deform them over time. A new study focuses on the bands, seen in red in the top image of Europa, that form as a result of these deformations. By simulating (bottom image) both the convective currents within the Europan ocean and the deformation of the ice over time, scientists are able to study how these geological surface features may have formed. Over the course of about a million years, material from the interior ocean works its way up into the center of a band. Because this process takes so long, the researchers point out that any attempt to collect material from the bands will yield “fossil” ocean material – essentially a glimpse of Europa’s ocean as it existed a million years ago rather than how it exists today! (Image credit: NASA; image and research credit: S. Howell and R. Pappalardo, source; submitted by Kam-Yung Soh)

  • Jupiter’s Swirls

    Jupiter’s Swirls

    Sometimes it amazes me that the Juno spacecraft was originally designed without any cameras onboard. The JunoCam instrument has produced stunning imagery of Jupiter thus far and shows no signs of stopping soon. The latest wonder is this false-color, high-contrast animation showing the motion of Jupiter’s clouds swirling and flowing past one another. 

    Now, this is not Jupiter as you would see it by eye. This animation is derived from two images taken 8 minutes and 41 seconds apart. In that time, Juno  covered a lot of distance, so the two images had to be mathematically re-projected so that they appeared to be taken from the same location. Then, by comparing relative positions of recognizable features in the two photos and applying some understanding of fluid mechanics, observers could calculate the probable flow between those two states. Although this is a coarse example, it’s the same kind of technique often used in fluid dynamical experiments when measuring how flows change between two images. (Image credit: NASA/JPL/SwRI/MSSS/G. Eichstädt, source; via EuroPlanet; submitted by Kam-Yung Soh)

  • Jupiter’s Belts and Zones

    Jupiter’s Belts and Zones

    Jupiter’s distinctive bands of colored clouds, known as belts and zones, have been an iconic part of the planet since they were first observed by Galileo. (The scientist, not the space mission!) They are considered part of Jupiter’s weather layer, the region of its atmosphere where storms reign. Thanks to gravitational measurements by the Juno spacecraft, we now know how deep these bands persist; they stretch about 3,000 kilometers into Jupiter! That means that Jupiter’s weather layer accounts for about one percent of the planet’s total mass. By comparison, Earth’s entire atmosphere makes up less than one millionth of its mass. What lies beneath Jupiter’s colorful clouds is also intriguing. The same gravitational measurements that indicate the weather layer’s depth also suggest that, beneath these storms, the rest of Jupiter rotates like a solid body. (Image credit: NASA, source; research credit: Y. Kaspi et al., submitted by Kam-Yung Soh)

  • Jovian Polar Vortices

    Jovian Polar Vortices

    Jupiter’s atmosphere is full of enduring mysteries, and its poles are no exception. Instruments aboard the Juno spacecraft have gotten a better look at Jupiter’s North and South poles than any previous mission, and what they’ve found raises even more questions. Both of Jupiter’s poles feature a central cyclone ringed by other, similarly-sized cyclones. The North pole has eight outer cyclones (top image), while the South pole has five (bottom image), shown above in infrared. Despite being close enough that their spiral arms intersect, the cyclones don’t seem to be merging into something like Saturn’s polar hexagon. For now, scientists don’t know how this arrangement formed or why it persists, but the longer Juno can study the vortices up close, the more we’ll learn. (Image credit: NASA/JPL-Caltech/SwRI/ASI/INAF/JIRAM; research credit: A. Adriani et al.; submitted by Kam-Yung Soh)

  • Juno’s Citizen Science

    Juno’s Citizen Science

    The Juno mission’s JunoCam has been producing stunning photos each time the spacecraft swoops past Jupiter. The instrument has a planning team, but its primary use is for citizen scientists, who have been suggesting images to take each orbit and have been processing those images. Most of the photos we see are like the one on the left above – photos that have been heavily color-enhanced to highlight details. The image on the right shows what Jupiter would look like to the human eye. Look closely, and you’ll catch many of the same colors and shapes in both photos. 

    At a recent conference, a member of JunoCam’s team presented scientific results that have come from the instrument, including analysis of Jupiter’s polar storm systems (8 vortices for the north pole and 5 for the south), tantalizing hints at Jovian equivalents to earthly cloud types, and more. She also announced a new Analysis page where members of the public can both see the science in progress and participate first-hand! (Image credit: NASA / SwRI / MSSS / G. Eichstädt / S. Doran; NASA / JPL-Caltech / SwRI / MSSS / B. Jónsson; via E. Lakdawalla; submitted by jshoer)