JUPITER. With a total of 92 known moons, Jupiter is passing Saturn again. In this race for satellites, twelve additional objects are added to the long list of Jovian moons.
Since December 2022, Jupiter has passed Saturn in the race for the planet with the most moons. The latest ranking was from 2019 and put Saturn at the top. According to an article published in Sky magazine
The majority of these new moons are objects located particularly far from Jupiter. Some are so far from the planet that they go around it in 550 days compared to 27.8 days for the Moon. These are small satellites, some of which could be debris from past collisions. The Juice mission which should take off next March could teach us more about the Jovian system and particularly about the satellites of the planet Jupiter.
An emblematic planet of the solar system, Jupiter is above all the largest of the 8 planets orbiting the Sun. Exceptional, it measures 139,820 kilometers in diameter.
Located 778.6 million kilometers from the Sun, Jupiter is the 5th planet in the solar system, placed between Mars and Saturn. It also borders the main asteroid belt which lies between Jupiter and Mars. Scientists believe that the gravitational force of Jupiter prevented the accretion of nearby objects. No planets therefore formed from these objects, leaving the asteroid belt as we know it.
Jupiter is a gas giant, characterized by its color striped with orange, white and brown bands, sometimes even blue, due to its composition and the movements of the winds present on its "surface". Its Great Red Spot is also a feature of Jupiter. First observed around 1664, it is a 15,000 kilometer long anticyclone within which extremely strong winds circulate.
The size of Jupiter allowed it to attract many objects passing nearby thanks to its great gravitational force. Some have thus placed themselves in orbit around it and constitute natural satellites, also called "moons".
There are currently 92 moons orbiting Jupiter. The last twelve were officially listed in December 2022. These are small moons, between 1.5 and 5 kilometers in diameter, which evolve at great distances from the gas giant. Some of these are likely debris from collisions with much larger moons that would have existed in the past. Debris from these encounters would have been captured by Jupiter's strong gravitational force. The discovery of these moons happened almost by chance, as a team of astronomers scanned the solar system in search of a mysterious planet, as National Geographic magazine explains.
Jupiter's four largest satellites are Io, Europa, Ganymede, and Callisto. These moons were discovered by Galileo in 1610 using his astronomical telescope. They are therefore called the Galilean satellites.
Io has the distinction of being the most volcanic satellite in the solar system. On its surface, 400 volcanoes are active, producing extraordinary eruptions, lakes and lava fountains several kilometers high. This volcanic activity is explained by the presence of the other moons of Jupiter. Indeed, Io is wedged between Jupiter, Ganymede and Europa. It thus undergoes their gravitational forces which deform its crust, heat the rock and produce magma.
Ganymede is Jupiter's largest moon. It measures 5,268 kilometers in diameter, which is more than one and a half times the size of our Moon. It is also the largest natural satellite in the solar system. It is even larger than the planet Mercury, which measures 4,879.4 kilometers in diameter.
Ganymede, Europa and Callisto are objects particularly studied by space agencies, because the latter present lakes of water under their crust and could therefore be potential candidates for the search for life forms.
The planet Jupiter turns out to be rather inhospitable to host a form of life. Without a solid surface, with extreme temperatures, it seems unlikely that life as we conceive of it could have developed there. On the other hand, scientists are very interested in its moons which could contain liquid water.
This is particularly the case of the Europe satellite, which, under a thick layer of ice, may contain an ocean of liquid water. This moon could have seen life develop. In this case, its life forms could resemble what is found in the seabed such as the Mariana Trench, the deepest place in the earth's crust. A study has thus highlighted the existence of living microorganisms more than 10 kilometers below the surface of the sea at the level of the Mariana Trench, feeding on the debris of other organisms which fall to the bottom of the ocean. .
“Discovering this possible ecosystem of microorganisms that survives through chemosynthesis in the deepest and darkest region of our oceans could give us valuable information about the potential for life in the depths of Europe,” reports Kevin Hand, NASA astrobiologist, to National Geographic magazine.
In 2023, Jupiter is visible during the first months of the year. You will be able to admire the largest planet in the solar system until mid-March. To not miss it, you will have to look above the western horizon at the beginning of the night, shortly after sunset. We will then have to wait until July to take advantage of the gas giant for longer. In the months that follow, it will be visible for longer and longer, night after night.
To admire Jupiter for a whole night, go on November 3, 2023. On this day, the giant planet will be at the opposition. This means that we will then be between the Sun and Jupiter which will be closest to the Earth. The giant planet will appear particularly large and bright in the sky during the nights before and after opposition.
Jupiter's opposition will take place on November 3, 2023. On this date, our planet will be between Jupiter and the Sun. The gas giant will then be closer to Earth than usual and it will be possible to observe it for much of the night. This is the ideal time to admire it in the sky.
To observe Jupiter from your garden, you don't need professional equipment! The planet is brighter than the stars in the sky and is therefore easy to spot. A telescope, an entry-level telescope or astronomical binoculars are enough to observe the planet and see its four largest satellites: Io, Ganymede, Callisto and Europa.
If you want to see more details of Jupiter, you will have to acquire slightly more technical equipment. A telescope less than 100mm in diameter will not be enough to learn more about Jupiter. With a 100mm diameter telescope, it is possible to see Jupiter's Great Red Spot which is nothing but a storm that has been raging for over 350 years. To observe the streaky cloud bands that give Jupiter its recognizable appearance, you'll need a telescope with a diameter of 150mm or more.
If you are looking to acquire a telescope, be aware that magnification is not everything. When the latter is too strong and the diameter is not sufficient, the image may become blurred. You will therefore not obtain a satisfactory image of your target. In the case of Jupiter, a magnification of 200 is sufficient for a diameter of 100 mm.
Now that you are equipped, all that remains is to point your telescope at Jupiter. To locate the gas giant, you can use an online sky map such as the one offered by the Stelvision site. In 2023, we will have to look for Jupiter in the constellation of the Whale.