Basics: Planet Jupiter
Main Image Credit: Enhanced image by Kevin M. Gill (CC-BY) based on images provided courtesy of NASA/JPL-Caltech/SwRI/MSSS, Published: 2019-03-21
Jupiter is named after the Roman king of the gods. This is no doubt due to its size. It is estimated to be over 2.5 times the size of all other planets in the solar system. Jupiter is a gas giant. This means that it has no known, or visible, hard surface like that of the 4 closest planets to the Sun. What you are seeing is gases, so effectively you are seeing its atmosphere.
Although it is over 746.14 million km from the sun, it is one of the brightest objects in the night sky, after Venus. It is easily viewed with the naked eye. This does not do it justice though, because views from amateur telescopes can be impressive. Bear in mind that you can even see the main moons of Jupiter with just binoculars. To see the impressive rings, you really need more magnification, like a standard reflector telescope.
Note that it is a little awkward when talking about the “surface” of Jupiter. Depending on the context, this article may switch from saying surface or atmosphere. The depth of the atmosphere makes it difficult to define which one is which.
Jupiter is known to have some of the most impressive surfaces features when viewed from space. It may even be considered more interesting looking than Earth (which is mainly shades of blue green and white). Note that some images are somewhat colour enhanced, so it is not necessarily exactly what you would see from space through a clear window.
The movement would be much more interesting to look at than static images. There is however a limitation as to what visual material can be sent back to earth. People have constructed animations, one of which can be seen somewhat on the video inside this page:
Note that even watching earth from space you would not see much movement. Due to the higher wind speeds of Jupiter it would be more likely; the closer you could get the better it would be visually.
Jupiter is actually similar to a star. If it were 80 times more massive it would likely be classed as a star (which is clearly a hypothetical concept, because it is NOT). The contents of what you see on the surface are similar materials to stars, hydrogen and helium. It is said by some that Jupiter is a “failed star”. This is due to its materials, but it is simply not large enough.
It has been posited that Jupiter may have a solid core. It would at least seem sensible to suggest there is! This could maybe even be the size of earth, but it is only theory at the present time. The decent into Jupiter’s lower regions would be highly impractical at this present point in time. It is extremely inhospitable. There was enough difficulty getting something onto the surface of Venus; descending into Jupiter would be much worse.
As stated already, Jupiter seems like mostly atmosphere. It is however very dense, so people do consider it part of the planet in a conceptually different way to terrestrial planets like Earth and Venus. Scientists are not absolutely clear on its lower boundary. It is after all a “gas” giant, gas being that which is assumed to be atmosphere. Compared to other planets, Jupiter’s atmosphere is huge.
This fun video describes the horrific results of trying to enter the “surface” of Jupiter. Remember it is really just for fun but it is based off known data:
The Galileo Jupiter Atmospheric Probe was one that was sent into the surface of Jupiter. It entered the surface of Jupiter on December 1995. It lasted almost an entire hour before becoming incapable of sending any more data. It took just a few minutes for it to decelerate from 170,590 kilometres per hour, to just 160 KM per hour.
Moons of Jupiter
Jupiter has an incredible array of moons, of all shapes and sizes. They are some of the most varied and are more like little planets of their own. Remember of course that a planet is directly in orbit around the main star of the system.
In order from closest to Jupiter, the 4 main moons (usually referred to as “Galilean moons”) are:
- Io – This is one of the most recognizable moons with its rich yellow surface and odd looking markings. It is highly volcanic.
- Europa – This is possibly one of the all time most intriguing moons for a variety of reasons. It is one moon that is theorized to possibly harbour microbial life. This is due to sub-surface liquid water.
- Ganymede – This is known to be the largest moon in our system. It is even larger than the planet Mercury, although Ganymede is only half of Mercury’s mass.
- Callisto – This is the third largest moon of the system. Saturn’s moon Titan is slightly larger. Callisto is considered the most cratered moons of the system. These craters are littered across the surface like bright white spots.
Image data: NASA/JPL-Caltech/SwRI/MSSS, Image processing: Kevin M. Gill CC BY, Published: 2021-Dec-17: