A Moon Ablaze:

Our solar system is a beautiful and diverse place. The wonders of Earth alone are breathtaking, so imaging a plethora of other worlds with their own geography, topography, and landscape is almost impossible to comprehend. One of the most remarkable objects that spirals around the Sun is Io, a Galilean moon of Jupiter. At first glance, something seems strange. After all, it does not have the characteristic glint of an icy moon. Instead, it is a mesh of yellow, red, white, and black patches. This strange assemblage of colors is due to the intensely active surface which, upon closer look, is scattered with volcanoes. These volcanoes release sulfur in large amounts, which then deposits on the surface.

Io is the only body in the Solar System other than Earth that is volcanically active. There are other moons such as Enceladus and Triton that spurt geysers of water ice. Cryovolcanoes (volcanoes that erupt ice or methane instead molten rock) have been theorized to exist on Saturn’s moon Titan and even Pluto. Yet Io alone is known to have flowing magma on its surface. So, what is it that makes Io so volcanically active? The main reason for this volcanic activity is the moon’s proximity to Jupiter. It is only 220,000 miles from the cloud tops of Jupiter (a distance shorter than that which separates the Earth and Moon), meaning that Jupiter’s powerful gravity can stretch the moon from side to side as it orbits around the planet. This tidal stretching creates intense heating in the moon’s interior, allowing for the release of molten rock on the surface.

Io and Jupiter are a dangerous duet, one that makes any mission to Jupiter a hazardous task. This is because of Io’s atmosphere and the ions it contains, which are then trapped in Jupiter’s magnetic field. As Io passes through the planet’s intense magnetic field, the sodium atoms ejected from the volcanoes become trapped and accelerated through the magnetic field. If humans will pass through the Jupiter system to explore its diverse moons, extreme measures will have to be taken so as not to expose the crew members to the radiation produced through the Jupiter-Io duet.

Active Lava Flows on the Surface

This diffuse atmosphere of sodium is not only dangerous. It also has a certain beauty. As the massive disk of Jupiter crosses the distant Sun, the sky will begin to glow faintly. This is the aurora of Io, a faint blue-green wisp of light that flickers in the sky. This reveals the existence of Io’s atmosphere and magnetic field.

Io’s Aurorae

If, in the far future, humans are capable of exploring the outer solar system, I believe that there will be bases on the moon’s surface whose sole task will be to generate hydrothermal energy using the moon’s internal heat. In addition, orbiting stations could perhaps be able to collect the energy stored in the particles trapped in Jupiter’s magnetic field. These are just ideas, but new sources of energy will have to be found in the outer solar system, where the Sun is too dim to power solar cells.

To end off the post, here are some wonderfully captivating images of Io:

Tohil Mons (taken by the Galileo spacecraft)
Volcanic Eruption
Io’s Landscape
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