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104

(*) Jupiter, for all intents and purposes, doesn't have a solid surface to stand on. Not any more than you could say that Earth's atmosphere has it, before you hit Terra Firma. It's an enormous ball composed of mostly Hydrogen and Helium, but also other heavier elements in smaller parts, and it's so massive that its own gravity compresses these gases into ...


49

The trajectory was not only "unhindered" - it was enhanced! Knowing mass of the planet you can calculate very precisely how the trajectory of a probe flying by will be affected. You modify the trajectory on arrival in such a way, that the departure trajectory will be exactly as desired. And due to some rather unintuitive physics caveats, you can make it so ...


45

Jupiter being a gas giant is not about its appearance, as another answer stated. It's only about the mass distribution of a planet. Jupiter's mass is 320 Earth masses, while we know from the Juno mission that the rock/ice in the core account for 5–25 of these Earth masses. So the rest of about 300 Earth masses is gas. Thus Jupiter is a gas giant. It is ...


25

They did not ! This is the trajectory of Voyager 1 at Jupiter. credits wikipedia


23

This is a pretty broad questions, as it would depend on which gas giant you have in mind. Excluding Uranus and Neptune as ice giants, this leaves us with Jupiter and Saturn in our own Solar system, and they're still hard to directly compare in terms of how hazardous environment they'd represent to an orbiting space station. But they have one deadly thing in ...


15

One reason they are called gas giants is because they are mostly composed of elements that are gaseous at Earth like temperatures and pressures. Jupiter is primarily composed of hydrogen with a quarter of its mass being helium, though helium comprises only about a tenth of the number of molecules. Jupiter's upper atmosphere is about 88–92% hydrogen ...


14

My 1965-vintage copy of Sourcebook On The Space Sciences has this to say: The model developed by DeMarcus in 1958 is regarded at present as the most acceptable for the interior of Jupiter. It postulates that the planet consists of 78% by weight of hydrogen molecules and the remainder helium ... calculations indicate that at a distance of about 0.8 times ...


14

There is an answer on wikipedia: Rogue planet: It is calculated that, for an Earth-sized object at a kilobar hydrogen atmospheric pressures in which a convective gas adiabat has formed, geothermal energy from residual core radioisotope decay will be sufficient to heat the surface to temperatures above the melting point of water.[13] Thus, it is proposed ...


11

Interesting question, to answer the question, gas planets do probably have a solid core, because the pressure is so enormous that the atoms connect into a crystal-like structure. We know that water for example can have more than 3 material states here. It is even possible/hypothesized that you get an metal if you compress a gas highly enough. This can ...


9

Live, yes. Thrive? No. The ISS and stations like it are not "benign environments" - that is, they are life sustaining, but not safe for long term habitation on the order of years. They lose air, they admit both EM and particulate radiation, and are only minimally protected from magnetic induction. The NASA lifetime space exposure limit is under 5 Seiverts ...


8

Talking about Jupiter, there was the Galileo Probe, also referred to as Jupiter Atmosphere Probe, which was dropped into the atmosphere of Jupiter in 1995. Its data is still the only data measured in situ on any gas giant. There are profiles for wind speed, temperature and pressure, besides other parameters, up to a depth of about 160 km (compared to ...


8

The Juno probe will be doing some of this for Jupiter's atmosphere. Due to the extreme densities involved it will be doing so from orbit; not by entering into it. From Wikipedia Scientific objectives Image of Jupiter aurora in UV by the Hubble Space Telescope. Bright streaks and dots are caused by magnetic flux tubes connecting Jupiter to its ...


6

The term "Ice Giant" is given to planets which are thought to have formed from materials in their ice phase, not because they are made of ice. The ices changed to gas and liquid during planet formation.


6

Eventually, yes but I don't think that it has much to do with the sun. Jupiter's magnetosphere shunts all of the solar wind (plasma) from the sun and Jupiter's atmosphere was also found to be quite turbulent. This indicates that Jupiter's winds are driven in large part by its internal heat rather than from solar input as on Earth. -nineplanets.org ...


6

As I remember, Saturn was often described as being less dense than water and thus able to float in a giant ocean, long before the probes. The orbiting natural satellites were used to measure the total masses and thus densities of the gas planets. James Blish coined the term "gas giant" to describe the outer planets about 1952 in a science fiction story, ...


6

No, you can't fly through the rings you can see without hitting lots and lots of dust-sized ice particles at high velocity. Your vehicle will not fare well. The ring material is not sparse in that sense. There is a wide distribution of particle sizes from boulders to dust. There's a lot more dust-sized, so that's what you need to worry about. (I wouldn'...


5

This formula assumes a constant gravitational acceleration over the whole height of the gas column - a reasonable assumption for Earth, as the atmosphere is thin compared to to the size of the planet. For a simple argument, if you assumed composition is the same, it's clear that the altitude change needed for pressure to change by a certain factor is less ...


4

For a spherically symmetric mass distribution in hydrostatic equilibrium: ${dP\over dr}=-g\rho$ where $P$ is the pressure, $r$ is the radius, $g$ is the gravitational acceleration as a function of $r$, and $\rho$ is the density of the gas as a function of $r$. Then you integrate up or down from some known conditions. $g$ as a function of $r$ is ...


4

A recent analysis of Voyager 2's flybys of Uranus and Neptune found that the weather layers on both planets are at most 1000km thick. This was done by modeling how density variations in the atmosphere would affect the spacecrafts trajectory by minutely varying the planets gravitational field. http://www.skyandtelescope.com/news/207909201.html


4

(This image shows that the rear side of Saturn ring is dark ) (this image shows the variation of rings brightness as the distance from earth the more closer the more brighter) The Saturn ring consist of 99% of water and the remaining impurities** The water is in the form of water ice since ice is a crystalline structure it reflection and refracts light ...


4

I've seen it in viewgraphs, but not in a serious proposal. I suspect that there will be more traditional probes (entry vehicles on parachutes) to Saturn and one of Neptune or Uranus, since we haven't done those yet, before a balloon would be attempted.


3

If the right chemical bath spews from hydrothermal vents on the floor of an ocean on this moon, then perhaps it could host creatures like the ones found around such vents on Earth. Here is a quote from an article on the subject in NASA Science News: Instead of photosynthesis, vent ecosystems derive their energy from chemicals in a process called "...


3

We can probe this matter a little more in-depth. This introductory reference describes all the giant or Jovian planets, noting that only the two more massive ones, Jupiter and Saturn, are made primarily of hydrogen and helium. Uranus and Neptune, which did not have as much material to work with and did not become powerful enough to draw large proportions ...


3

The orbital period of a satellite tells you the mass of the object it's orbiting. Thus we could weigh the gas giants and know that they were so light they had to be almost all gas.


3

Actually Mazura is wrong, Callisto the moon of Jupiter has a mean temperature of 134 Kelvin, Jupiter has a cloudtop temperature of 165 Kelvin. So it is warmer, but just by 30 degrees. The Jupiter's internal heat really shows below the top clouds, with the core being 36000 Kelvin hot. The freezing point of hydrogen is 13.99 Kelvin. Any "gut feeling" is wrong ...


3

There are two factors at work here: The rings of Saturn are made of much more reflective material (water ice) than those of Jupiter, Uranus or Neptune. They simply have much more matter in them. This wikipedia article and this one suggest a mass for Saturn's rings ($1-3\times 10^{19}$kg) which is at least 1000 times greater than that of Jupiter's rings ($10^...


3

Just about any data concerning a planet can contribute to our understanding of its internal structure one way or another. That said, probably the most powerful techniques at the moment are observation of the planets gravitational and magnetic fields and how they vary in space and time. Observing the gravitational field amounts to accurately tracking the ...


3

@SteveLinton gave the primary investigations for determining a giant planet's internal structure: gravity field structure and magnetic field structure. One minor correction: while the round-trip propagation times ("ranging" data) are useful, the most accurate data are Doppler data of the spacecraft's velocity vs time, as described in Arv Kliore's paper on ...


2

No, they don't have. Cores of these gas giants are actually solid, but above them, there's a thick layer of gas, with thousands of kilometres of thickness. Obviously, its concentration is increasing as you approach the core, but it's not solid. Bodies are sinking into it, like into wateror quicksand. Except if they have something with smaller density than ...


2

Yes, and that's believed to be the source of Jupiter's gigantic magnetosphere. It is also a possible explanation for bizarre cooling of Cassiopeia A. So that's at least two immediate effects of large quantities of metallic hydrogen present in a celestial body; formation of a magnetosphere and faster cooling of their outer cores. Both of these effects are ...


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