Surface Of Jupiter Research Articles

Zonal flow driven by deep convection in the major planets

The cause of the fast zonal winds on the large gas planets is disputed. To investigate their possible origin by convection in the planets' molecular hydrogen layer, I study simple numerical models of thermal convection in a rotating sphere at low Ekman numbers for Rayleigh numbers up to 100 times critical. With stress‐free boundaries and high Rayleigh number it is possible to reproduce the observed magnitudes of the zonal and non‐zonal flow components at the surfaces of Jupiter and Saturn. While only three flow bands are found for a thick convecting shell, the number increases to seven for a shell with an inner‐to‐outer radius of 0.6.

Formation of cycloidal features on Europa.

Cycloidal patterns are widely distributed on the surface of Jupiter's moon Europa. Tensile cracks may have developed such a pattern in response to diurnal variations in tidal stress in Europa's outer ice shell. When the tensile strength of the ice is reached, a crack may occur. Propagating cracks would move across an ever-changing stress field, following a curving path to a place and time where the tensile stress was insufficient to continue the propagation. A few hours later, when the stress at the end of the crack again exceeded the strength, propagation would continue in a new direction. Thus, one arcuate segment of the cycloidal chain would be produced during each day on Europa. For this model to work, the tensile strength of Europa's ice crust must be less than 40 kilopascals, and there must be a thick fluid layer below the ice to allow sufficient tidal amplitude.

Europa: life elsewhere?

At the Jet Propulsion Lab. scientists and engineers are spearheading far-reaching research efforts to prove beyond all doubt that life exists, or once existed, elsewhere than on Earth. In their most promising initiative, they hope to land a probe on the surface of Jupiter's moon Europa, considered a likely site for extraterrestrial life, within the next 15 years. As planned this autonomous vehicle will melt down through the ice to a vast ocean below where it will conduct tests to investigate if life exists there.

Once, Maybe Still, an Ocean on Europa

PLANETARY SCIENCEBOSTON-- Does the mightiest ocean in the solar system lie beneath the ice-sheathed surface of Jupiter's moon Europa? The tortured appearance of the moon's surface had persuaded many scientists, but skeptics had argued that a solid layer of ice slightly warmed by Europa's internal heat could churn slowly, reshaping the surface without ever melting. At last week's annual meeting here of the Division for Planetary Sciences of the American Astronomical Society, however, researchers presented new analyses of Europa's surface scars that had even the skeptics agreeing that, either now or in the recent past, an ocean stirred just beneath the icy surface.

Cracked cue ball

The latest images sent by the Galileo spacecraft reveal that the surface of Jupiter's moon Europa may have contained a layer of “warm ice” or even liquid water. In fact, planetologists are wondering if perhaps it still does.Photos taken earlier this summer show Europa to have a crust of smooth white and brown‐tinted ice scarred by long, jagged cracks; some scientists have said the moon looks like a cracked cue ball. “The scale of fracture patterns—extending a distance equivalent to the width of the western United States—dwarf the San Andreas fault in length and width,” said Ronald Greeley, a geologist from Arizona State University and a member of the Galileo imaging team. The cracks are believed to have been caused by the stress of tidal forces created by Jupiter's gravity. Warmth generated by tidal heating also may have been sufficient to soften or liquefy some of the ice.

Plasma effects on the interaction of a comet with Jupiter

I consider some plasma effects to be expected when the fragments of Comet Shoemaker‐Levy 9 crash into Jupiter. Emphasis is put on pre‐impact effects, and on the possibility of significant radio emission. It is shown that an ionizing shock will develop at altitudes below about 600 km, and that significant ionization will exist above that altitude. The incoming comet and its surroundings will then represent a rapidly moving conductor in a strong magnetic field and will induce large currents in Jupiter's magnetosphere, similar both qualitatively and quantitatively to a way in which Io interacts with Jupiter's magnetic field and with the plasma of the torus. This process is thought to be involved in the generation of decametric radiation, so that the impact of the comet may also produce such radiation. The power involved in this interaction is estimated to be at least 1/15th of the power due to Io, and its duration to be for 10‐20 s before the comet's impact with the surface of Jupiter.

Rotational distortion on the surfaces of Jupiter and Saturn

Having formulated the Clairaut second-order differential equations up to the fourth order in superficial distortion due to Hensen's coefficients in the previous article (El-Sharawyet al., 1989 III, hereafter denotes by SM3), we are now in a position to solve them. In this paper we shall discuss the methods of solving the Clairaut theory, to give an explicit form about the distortion of the surfaces of Jupiter and Saturn, numerically up to the fourth-order.

The impact of fragment “L” of comet SL-9 on Jupiter

Filtergrams of high spatial and temporal resolution were obtained in the methane band centred at 892 nm during the impact of fragment L of comet Shoemaker-Levy 9 on Jupiter. The light curve shows two maxima of an emission ball observed above the limb shortly after the impact. The second maximum was the brightest and had a short life time of about 90 seconds. During it's life, the apparent height of the emission ball declined towards the surface of Jupiter; the amount of displacement is larger than the expected effect caused by Jupiter's rotation. About half an hour after the impact, a domelike feature became visible when the location of the impact rotated into the illuminated hemisphere of Jupiter.

Sputtering of SO2by high energy ions

Abstract Sputtering yields of solid SO2 by high energy ions were measured in order to study the mechanism for sputtering dielectrics with ions in the electronic stopping power region. The incident ions were helium and fluorine with energies ranging from 1.5 MeV to 25 MeV. Yields as high as 7000 SO2 molecules/incident F ion were measured; the 1.5 MeV 4He beam had a sputtering yield of 50. The data are compared to yield measurements made on UF4 and H2O targets. There is a striking similarity in the yield as a function of the incident F energy for all three targets. The data compare favorably with theoretical yield curves based on a new model for the sputtering which considers the electronic excitations induced in the target by the incident beam. Measurements and calculations of this sort are also useful in understanding processes which occur on the surface of Jupiter's satellite Io, which is covered with SO2 frost and bombarded by energetic ions trapped in the Jovian magnetosphere.

On the rotation of Jupiter

Summary. Jupiter's non-uniform rotation is reflected in the use by observers of three systems for measuring longitude: system I which rotates in the period 9 h 50 m 30.003 s, system II in 9 h 55 m 40.632 s and system III in 9 h 55 m 29.710 s. Disturbances of Jupiter's visible surface of dense ammonia-cirrus cloud within a narrow equatorial zone of about 7° latitudinal half-width show comparatively little motion relative to system I, and most (but not all) higher-latitude atmospheric disturbances including the Great Red Spot and the three white ovals move only slowly in system II. Finding neither system I nor system II particularly convenient for monitoring sources of intense non-thermal radio-emission from Jupiter, radio-astronomers introduced system III with respect to which the radio sources show little systematic movement. The interpretation of Jupiter's non-uniform rotation involves considerations of the hydrodynamics of the atmosphere of the planet and the hydromagnetics of the deep interior. Jovian radio sources are extensive regions of plasma tied to the lines of force of the magnetic field B surrounding the planet. These in turn are intimately linked to material at the outer surface of Jupiter's electrically-conducting fluid core, mean radius rc, which consists largely but not entirely of metallic hydrogen. A method for determining rc from observations of secular changes in B in the accessible region above the visible surface of the planet, mean radius rs= 69 700 km, has recently been proposed and applied using the few available data, giving rc greater than about 50 000 km and possibly as large as 63 000 km. The difference in period between system I and system II reflects the presence at the upper cloud level of a sharply-bounded equatorial jet stream within which the atmosphere moves at about 100 ms−1 in a westerly (eastward) sense relative to higher latitude parts of the atmosphere and to the deep interior. The width of the equatorial jet can be accounted for satisfactorily by fairly general dynamical arguments, which predict that the apparently much stronger equatorial jet (400 m s−1) on Saturn will be found to be about twice as wide as that on Jupiter.

Tidal flows in binary systems

The expressions of the tidal velocity in not very close binaries (double stars, the Sun and a planet, a planet and a satellite) are derived and applied in particular to white dwarfs and the giant planets of the solar system. The magnitude of the velocity on the surface of Jupiter is estimated to be about 0.5 cm s−1. In white dwarfs the velocities of the order of tens m s−1 may be encountered, and they can influence their evolution. The symmetry of the tidal flows is noted to be suitable for the magnetic field generation.

Thermal structure of Jupiter

view Abstract Citations (102) References (14) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Thermal structure of Jupiter Hubbard, W. B. Abstract The observed net flux of energy from the surface of Jupiter is assumed to derive from the thermal energy of the protons in the interior of the planet The thermodynamics and transport properties of metallic hydrogen at finite temperature are discussed, and the temperature distribution in the interior is calculated for various assumed luminosities and atmospheric boundary conditions. The resulting mod- els possess deep convective envelopes for surface fluxes in excess of _.~,1O2 ergs cm~ sec' and are wholly convective for surface fluxes exceeding ~-~-`1O~ ergs cm~ sec' Publication: The Astrophysical Journal Pub Date: June 1968 DOI: 10.1086/149591 Bibcode: 1968ApJ...152..745H full text sources ADS |

Classics of Science: Surface of Jupiter

Classics of Science: Surface of Jupiter

On a probable Instance of periodically recurrent Disturbance on the surface of Jupiter

On a probable Instance of periodically recurrent Disturbance on the surface of Jupiter

The Remarkable White Spot on Jupiter

EARLY in the present month this singular object became obscured, so that on January 1 I could scarcely distinguish it at all, and on the 3rd, 5th, and 6th it was noted as extremely faint. The origin of the spot's disappearance was obvious. A dark mass on the north border of the great south belt (and therefore in the same latitude as the white spot) appeared on December 14; it followed the white spot 1h. 4m., according to observations by Mr. A. S. Williams at Brighton. The dark spot moved with more rapidity than the latter, and soon overtook it, so that as the former swept over it, its disappearance was complete. On January 6 the white spot was seen struggling through the southeast limits of the dark patch. On January 7 it had further freed itself, and I saw it much plainer, though it still continued somewhat faint. On January 9 it was bright, and evidently on the point of regaining its normal brilliancy. The dark patch referred to is obviously of the same character as the train of black spots visible on one of the northern belts last winter; they move with even greater velocity than the white spot, and are somewhat evanescent as regards duration. They appear to be excrescences from the surface of Jupiter, and as they near the outer envelopes, are dispersed into longitudinal bands; in fact, it is these dark spots which sustain the decided tone of the belts, for the latter show a disposition to become fainter, until reinforced by the commingling of these dark eruptions.

On some recent changes in the surface of Jupiter

On some recent changes in the surface of Jupiter

On the Periodical Changes in the Belts and Surface of Jupiter

On the Periodical Changes in the Belts and Surface of Jupiter

On an Appearance on the Surface of Jupiter, which passed rapidly over the Disk of the Planet

On an Appearance on the Surface of Jupiter, which passed rapidly over the Disk of the Planet