# Tag Info

60

The asteroid belt is affected by Jupiter's gravity. There are stable orbits inside of Jupiter's orbit. Jupiter's Hill Sphere has a radius of 53 million km. If you are more than 53 million km from Jupiter, then the Sun's gravity dominates and you can orbit the sun. But Jupiter orbits 780 million km from the Sun, so there is plenty of space between Mars and ...

48

It’s because they are much smaller than Io. Tidal forces are differential forces, that is, they result from the difference in gravitational pull on one side of a body compared to the other. When an object is small, the difference in distance to the two sides of it is necessarily small as well. According to Wikipedia, Amalthea, the largest of those four ...

40

No. Besides the 13 Jupiter-masses required to ignite deuterium burning, and make Jupiter into a Brown Dwarf, there is a clear difference between the formation pathways of Brown Dwarves and Gas Giants. Gas Giants are planets, that form via processes in their parent protoplanetary disc. Contrasting this, Brown Dwarves form via direct fragmentaion of the ...

35

It does drift relative to other parts of the atmosphere. The lack of a surface makes defining the actual rotation period of Jupiter rather difficult. The currently accepted value of 9h:55m:33s is based on observations of the average rotation of the interior, inferred from satellite measurements. The Red Spot was previously used to define the rotation period, ...

31

As written on Wikipedia page about this: On Earth, the analemma appears as a figure-eight, but on other Solar System bodies, it may be very different due to the interplay between the three parameters determining the analemma: axial tilt of each body, eccentricity of the body's elliptic orbit, and position of either apses or equinoxes. Thus, if either of ...

31

The part of your intuition that is correct is that Jupiter pulls the Sun towards it. The problem is that "pulls towards" does not mean "brings closer"! The gravitational force results in an acceleration towards an attracting body, which is not a displacement or even the derivative of displacement, but the second derivative of displacement....

30

But why can't Jupiter be a Y Dwarf who is in the binary relationship with the Sun? There are two reasons: One is that Jupiter is too small to have ever undergone fusion of any sort. To qualify as a brown dwarf, an object needs to be large enough to have undergone deuterium fusion in its core. This requires a mass of at least 13 Jupiter masses. The other is ...

28

In an isothermal atmosphere, the exponential scale height of the atmosphere is $$h \sim \frac{k_\mathrm B T}{\mu g},$$ where $g$ is the gravitational field, $\mu$ is the mean mass of a particle and $T$ is the temperature (in kelvin). i.e. The pressure/density of the atmosphere falls exponentially, with an e-folding height given by the above expression. I ...

26

Believe it or not, Jupiter isn't too consistent. Take a look at these pictures, the first taken in 2009 and the second taken in 2010: and Quite the difference, eh? Why? Jupiter's atmosphere is made of zones and belts. Zones are colder and are composed of rising gases; they are dark-colored. Belts are warmer and are composed of falling gases; they are light-...

24

Roche limit happens where the gravity of the object, trying to pull the object together, becomes smaller than the tidal force (trying to pull the object apart). But the astronaut is bound by not gravity, rather by the electromagnetic interaction between his/her atoms. The own gravity of the astronaut is negligible, compared to the electromagnetic interaction....

23

Mass. The more massive a body, the larger the gap between its lowest and highest orbit; the range of speeds at which a random body entering its gravity is likely to remain as its satellite. Sun has millions of satellites if you count all the asteroids; smaller planets tend to have one or two moons at most (Pluto with five being a notable and not fully ...

23

It's red because it's a 'sunburn'. The clouds in the red spot reach to higher altitudes than the surrounding ones and are more exposed to solar UV radiation, which in turn changes the structure of some of the organic molecules etc. This is at least the explanation suggested by recent data from NASA's Cassini mission, see this 5-day-old press release.

22

Yes, you can see it (I have seen Io's shadow on Jupiter and we were happy it was visitor night so that we could share the view with guests) A 50cm mirror and 125x magnification allows you to see it when the air is not too disturbed and when you know where and when to look. Likely a somewhat smaller telescope will do, too, as light sensitivity is not too ...

21

Rings are made up of tiny (and not so tiny) pieces of rock and ice that are in some way the bits "left over" from the formation of the planet. The theory involves the Roche limit - and is that particles that are already within this limit can't accrete into a larger body because of the tidal forces involved. Another theory is that they are formed when a moon ...

20

Per the Carnegie Science article that Magic Octopus Urn linked from NASA in the comments, a Carnegie Science team led by Scott S. Sheppard noticed something new in spring of 2017 (though some observations occurred as early as 2016). It took a year to confirm the discovery of the new moons. Ten of the moons orbit in the outer swarm of moons, which is one of ...

19

Bigger is better. Most moons, especially those of gas giants, are not "formed", they are just "captured" (unlike our Moon, which could have been captured, but probably was formed in a much more exciting way). Jupiter is the most massive planet in the solar system. It stands to reason that it has a larger region of gravitational influence (where its ...

19

Every Galilean moon and inner moon go into lunar eclipse once per orbit. How often is there a lunar eclipse of the Jovian moons? I set up a little animation of the Galilean moons (I didn't include the inner moons), and made a few assumptions (negligible moon size, sun at infinity, perfectly circular orbits) and found that there is a lunar eclipse in the ...

19

Yes, as with all other storms, the Great Red Spot is dynamic, so it constantly changes its size and shape and it shifts and drifts and is not just "locked in a definite position". According to nasa.gov: The new findings indicate that the Great Red Spot recently started to drift westward faster than before. The storm always stays at the same ...

18

The mass of the asteroid main belt is estimated at 4% the mass of our moon according to Wikipedia so any object formed from the aggregation of that mass would not be a planet. It would be the size of a very small moon. Even if all the asteroids in the solar system were combined, the total mass would be below a third of the moon's mass.

17

The largest main belt asteroid is 1 Ceres, which alone contains almost a third of the total mass of the whole main asteroid belt. Ceres is large enough to be in hydrostatic equilibrium, i.e. its own gravity is strong enough to pull it into a roughly spherical shape. Since the mass of a spherical planet scales as the cube of the diameter (assuming constant ...

17

Jupiter does not have a "surface" and nor is there anything but an arbitrary division between interplanetary space and where its atmosphere begins. The crushing pressure is its atmospheric pressure. The deeper into the atmosphere you go, the greater the column of gas that lies above you. It is the weight of this column of gas that is responsible for the ...

17

Jupiter won't evolve into a star, it is not big enough. A body would have to have about 80 times the mass of Jupiter for there to be significant fusion occurring in the core. The end of life of the Sun won't change the mass of Jupiter. Jupiter will continue to orbit the Sun as it evolves into a red giant. Although the solar wind will be much much more ...

17

This has been an area of controversy for quite some time now, with no clear resolution (if you'll pardon the pun). There's been interest in supporting or refuting claims that observers were able to see the moons with the naked eye before Galileo. There are, of course, two major impediments (which you might well know about): brightness and angular separation ...

17

There are four moons that are closer to Jupiter than Io with higher eccentricities, yet they don't seem to have any volcanism at their surface. Only one of those innermost moons (Thebe) has an eccentricity higher than that of Io. The other three have lower eccentricities. The reason they don't exhibit volcanism is because they are too small. The largest of ...

17

Congratulations on your purchase. The first pictures dont' show anything much. Just a out-of-focus blur. The last one shows Jupiter and three of its moons. I've overlaid the image onto a simulated image from stellarium (at about 10pm BST, the moons move pretty quick so you need an exact time!): You can clearly see which moon is which, and why Europa is ...

16

That's no good idea. Earth wouldn't necessarily fall into Jupiter in the short run, provided it orbits Jupiter fast enough (within about 1.7 days), and on a circular orbit, but we would risk to collide with Io, destroy it by tidal forces, or change its orbit heavily. The other Galilean moons would get out of sync and change their orbits over time. Tides ...

16

Nothing "escapes" a BH - in the sense that a signal originating inside the event horizon remains forever inside. If something is observed moving away from the BH, then it was generated outside the event horizon. If it was generated inside, it would never be observed at all, forever and ever. Gravity itself does not "escape" a BH - and neither does "not ...

15

we see that its features didn't change largely over many years Jupiter is huge. It is 11 earths across, and 1300 times our volume. The clouds/bands we can see are vastly larger than Earth's entire ecosystem and that means they have a lot more inertia. Also consider our observation timespan. We have been watching Jupiter* for under 2 centuries, watching it ...

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