Starship Asterisk*

APOD Robot wrote:and attempt to determine if Jupiter has a solid surface underneath these fascinating clouds.

Coil_Smoke wrote:I figure there must be transition zones where Jupiter's atmosphere is compressed into a liquid phase then solid phase below that. If no terrestrial materials are found to be part of Jupiter's make up, what about Metallic Hydrogen as a candidate for a solid surface below all that circulation and turbulence ? There is something down there. I was surprised by persistent 'Bruises' left from comet impacts. Something below the clouds kept those wounds from simply blowing away.

Donald Pelletier wrote:Over the next few years ????, Juno will continue to orbit and probe Jupiter, determine atmospheric water abundance, and attempt to determine if Jupiter has a solid surface underneath these fascinating clouds.
"Over the next few months" will be more appropriate i think because Juno is schedule to crash into Jupiter's atmosphere on october 2017 (https://en.wikipedia.org/wiki/Juno_(spa ... ntegration)

Mulsar11 wrote:Everything you see in the video is AMAZING! One of the amazing things is toward the end. In one of the bands of "clouds" is a series of white "storms", that look almost equally space one after the other and of almost equal size going up to the top of the frame. This is very curious to me to see this detailed repeatability unless there is some physical structure/process that disturbs the otherwise semi chaotic flow of the "weather" on Jupiter. Anybody have any thoughts?

SeedsofEarth wrote:I must ask you, why do we see no cloud movement during this pass? Surely the Juno craft is not moving as fast as the video implies. It would not take it six weeks to complete an orbit if that were the case, would it? I really expected to see the clouds moving around, swirling and sweeping across the planet as they do on older videos sent back from other crafts approachiong and passing by Jipiter? In this video, the clouds appear to be static, as if the planet were merely a plastic globe with a photograph of Jupiter superimposed over it.

Nitpicker wrote:Magnificent! Thank you.

othermoons wrote:Relative to Earth, Jupiter is much further away therefore much colder yet the core temperature is much much hotter. The dense clouds totally and ominously cover the surface; however, is there a chance that the surface area may not be as hot as we thought?

Chris Peterson wrote:

othermoons wrote:
Relative to Earth, Jupiter is much further away therefore much colder yet the core temperature is much much hotter. The dense clouds totally and ominously cover the surface; however, is there a chance that the surface area may not be as hot as we thought?

The interior temperature of the planets is largely unrelated to the distance from the Sun. Interior temperature is determined by residual heat of formation and by radioactive decay.

https://en.wikipedia.org/wiki/Saturn#Internal_structure wrote:
<<Saturn has a hot interior, reaching 11,700 °C at its core, and it radiates 2.5 times more energy into space than it receives from the Sun. Jupiter's thermal energy is generated by the Kelvin–Helmholtz mechanism of slow gravitational compression, but this alone may not be sufficient to explain heat production for Saturn, because it is less massive. An alternative or additional mechanism may be generation of heat through the "raining out" of droplets of helium deep in Saturn's interior. As the droplets descend through the lower-density hydrogen, the process releases heat by friction and leaves Saturn's outer layers depleted of helium. These descending droplets may have accumulated into a helium shell surrounding the core.>>

https://en.wikipedia.org/wiki/Neptune#Internal_heating wrote:
<<Uranus only radiates 1.1 times as much energy as it receives from the Sun; whereas Neptune radiates about 2.61 times as much energy as it receives from the Sun. Neptune is the farthest planet from the Sun, yet its internal energy is sufficient to drive the fastest planetary winds seen in the Solar System. Depending on the thermal properties of its interior, the heat left over from Neptune's formation may be sufficient to explain its current heat flow, though it is more difficult to simultaneously explain Uranus's lack of internal heat while preserving the apparent similarity between the two planets.

Note: At a depth of 7,000 km, the conditions may be such that methane decomposes into diamond crystals that rain downwards like hailstones. Very-high-pressure experiments at the Lawrence Livermore National Laboratory suggest that the base of the mantle may be an ocean of liquid carbon with floating solid 'diamonds'.>>

Chris Peterson wrote: I don't believe there is any need to invoke some sort of solid surface below the clouds to explain the persistence of atmospheric disturbances caused by impacts. It can simply be a matter of scale and the fact that the atmospheric flow is substantially laminar over large areas.

Nitpicker wrote:

Chris Peterson wrote: I don't believe there is any need to invoke some sort of solid surface below the clouds to explain the persistence of atmospheric disturbances caused by impacts. It can simply be a matter of scale and the fact that the atmospheric flow is substantially laminar over large areas.

I don't think laminar is the correct word here. The flow in the Jovian atmosphere is highly turbulent.

Chris Peterson wrote:

Nitpicker wrote:

Chris Peterson wrote: I don't believe there is any need to invoke some sort of solid surface below the clouds to explain the persistence of atmospheric disturbances caused by impacts. It can simply be a matter of scale and the fact that the atmospheric flow is substantially laminar over large areas.

I don't think laminar is the correct word here. The flow in the Jovian atmosphere is highly turbulent.

It's also highly laminar- certainly across latitudes, and probably with height, as well. There is turbulence in places (particularly across boundaries), but large scale structure is not destroyed, because the turbulence is local.

Nitpicker wrote:

Chris Peterson wrote:

Nitpicker wrote:
I don't think laminar is the correct word here. The flow in the Jovian atmosphere is highly turbulent.

It's also highly laminar- certainly across latitudes, and probably with height, as well. There is turbulence in places (particularly across boundaries), but large scale structure is not destroyed, because the turbulence is local.

Technically, it is not highly laminar, but less turbulent. The technical basis for determining whether flow is laminar or turbulent is Reynolds number (Re), and the Re values characterizing the flows in the visible cloud formations, are too high to be considered laminar. But there is certainly a wide range in the degree of turbulence. I may be arguing a technical point, but laminar flow is fairly unusual and requires small scales and/or low velocities and/or high viscosities.

Nitpicker wrote:

Chris Peterson wrote:

Nitpicker wrote:
The flow in the Jovian atmosphere is highly turbulent.

It's also highly laminar- certainly across latitudes, and probably with height, as well. There is turbulence in places (particularly across boundaries), but large scale structure is not destroyed, because the turbulence is local.

Technically, it is not highly laminar, but less turbulent. The technical basis for determining whether flow is laminar or turbulent is Reynolds number (Re), and the Re values characterizing the flows in the visible cloud formations, are too high to be considered laminar. But there is certainly a wide range in the degree of turbulence. I may be arguing a technical point, but laminar flow is fairly unusual and requires small scales and/or low velocities and/or high viscosities.

https://en.wikipedia.org/wiki/Rossby_number wrote:
<<The Rossby number (Ro) named for Carl-Gustav Arvid Rossby, is a dimensionless number used in describing fluid flow. The Rossby number is the ratio of inertial force to Coriolis force. It is commonly used in geophysical phenomena in the oceans and atmosphere, where it characterizes the importance of Coriolis accelerations arising from planetary rotation.

The Rossby number (Ro) is defined as:

---

where U and L are, respectively, characteristic velocity and length scales of the phenomenon and f = 2 Ω sin φ is the Coriolis frequency, where Ω is the angular frequency of planetary rotation and φ the latitude.

A small Rossby number signifies a system which is strongly affected by Coriolis forces, and a large Rossby number signifies a system in which inertial and centrifugal forces dominate.>>