Jupiter’s Moons
Jupiter has 79 moons, 53 are named and 26 are awaiting names. There are many interesting moons orbiting the planet, but the ones of most scientific interest are the first four moons discovered beyond Earth—the Galilean satellites (Io, Europa, Ganymede, Callisto).
ᴬ ᴺᴬˢᴬ ˢᵖᵃᶜᵉᶜʳᵃᶠᵗ ˢᵉᵉˢ ᵃ ᵛᵒˡᶜᵃⁿᶦᶜ ᵉˣᵖˡᵒˢᶦᵒⁿ ᵒⁿ ᴶᵘᵖᶦᵗᵉʳ’ˢ ᵗʰᶦʳᵈ⁻ˡᵃʳᵍᵉˢᵗ ᵐᵒᵒⁿ. ᴵᵐᵃᵍᵉ ᶜʳᵉᵈᶦᵗ: ᴺᴬˢᴬ/ᴶᴾᴸ/ᵁⁿᶦᵛᵉʳˢᶦᵗʸ ᵒᶠ ᴬʳᶦᶻᵒⁿᵃ
Io is the most volcanically active body in the solar system. Io's surface is covered by sulfur in different colorful forms. As Io travels in its slightly elliptical orbit, Jupiter's immense gravity causes "tides" in the solid surface that rise 300 feet (100 meters) high on Io, generating enough heat for volcanic activity and to drive off any water. Io even has lakes of molten silicate lava on its surface.
ᴺᴬˢᴬ'ˢ ᴱᵘʳᵒᵖᵃ ᶜˡᶦᵖᵖᵉʳ ᵐᶦˢˢᶦᵒⁿ ᶦˢ ᵇᵉᶦⁿᵍ ᵈᵉˢᶦᵍⁿᵉᵈ ᵗᵒ ᶠˡʸ ᵇʸ ᵗʰᵉ ᶦᶜʸ ᴶᵒᵛᶦᵃⁿ ᵐᵒᵒⁿ ᵐᵘˡᵗᶦᵖˡᵉ ᵗᶦᵐᵉˢ ᵃⁿᵈ ᶦⁿᵛᵉˢᵗᶦᵍᵃᵗᵉ ʷʰᵉᵗʰᵉʳ ᶦᵗ ᵖᵒˢˢᵉˢˢᵉˢ ᵗʰᵉ ᶦⁿᵍʳᵉᵈᶦᵉⁿᵗˢ ⁿᵉᶜᵉˢˢᵃʳʸ ᶠᵒʳ ˡᶦᶠᵉ. ᴵᵐᵃᵍᵉ ᶜʳᵉᵈᶦᵗ: ᴺᴬˢᴬ/ᴶᴾᴸ⁻ᶜᵃˡᵗᵉᶜʰ/ˢᴱᵀᴵ ᴵⁿˢᵗᶦᵗᵘᵗᵉ
Europa may be the most promising place in our solar system to find present-day environments suitable for some form of life beyond Earth. There is very strong evidence suggesting Europa's ocean is in contact with rock. This is important because life as we know it requires three key basic "ingredients": liquid water, an energy source, and organic compounds to use as the building blocks for biological processes.
Europa could have all three of these ingredients, and its ocean may have existed for the whole age of the solar system, long enough for life to begin and evolve there. It's surface is mostly solid water ice. It is crisscrossed by fractures.
ᴺᵉʷ ᵛᶦᵉʷ ᵒᶠ ᴶᵘᵖᶦᵗᵉʳ’ˢ ˡᵃʳᵍᵉˢᵗ ᵐᵒᵒⁿ ᴳᵃⁿʸᵐᵉᵈᵉ, ᶠʳᵒᵐ ᵗʰᵉ ᴶᵘⁿᵒ ᶠˡʸᵇʸ ᵒⁿ ᴶᵘⁿᵉ ⁷, ²⁰²¹. ᴵᵐᵃᵍᵉ ᵛᶦᵃ ᴺᴬˢᴬ/ ᴶᴾᴸ/ ˢʷᴿᴵ/ ᴹˢˢˢ/ ᴷᵉᵛᶦⁿ ᴳᶦˡˡ/
Ganymede is the largest moon in the solar system (larger than the planet Mercury), and is the only moon known to have its own internally generated magnetic field.
It can be heard whistling and hissing in audio recordings made from plasma wave science data returned by NASA's Galileo spacecraft.
ᴵᵐᵃᵍᵉ ᶜʳᵉᵈᶦᵗ: ᴺᴬˢᴬ/ᴶᴾᴸ/ᴰᴸᴿ
Callisto's surface is extremely heavily cratered and ancient—a visible record of events from the early history of the solar system. Callisto is Jupiter’s 2nd largest moon and the 3rd largest moon in our solar system. It’s about the same size as Mercury. Its surface is 4 billion years old.
There is evidence of a subsurface ocean on Callisto, putting Callisto on the list of possible places where life could exist beyond Earth.
