Jupiter is a striking feature of our Solar System. The largest planet by far, and home to incredible storms larger and more powerful than anything on Earth, Jupiter has recently been thrown into focus with some incredible new images. Recent looks have shown us developments that have thrown what we know about the planet into disarray. Slowly, using information gathered by the Juno space mission, scientists are discerning exactly what is going on with the planet, and the changes it's undergoing that we have never seen before.
But one of the most striking features of Jupiter is it's moon Io. And scientists were very fortunate that Juno happened to be passing by as an incredible eclipse occurred.
Io is one of the superstars of the cosmic world. A roiling volcanic world regularly shooting plumes of fire into space. It was the first and remains the only example of extraterrestrial volcanic activity that we have discovered so far. Examining Io gives mankind a look at the ancient past of the Earth, as in primordial days it was similar volcanic and ever-shifting.
The Black Spot
The moon takes 1.77 days to orbit the planet. Due to the enormous amount of gravity present on Jupiter, the friction created causes the huge amount of heat that is present on Io. Because Io is also the closest of the 3 moons in its orbit, it displays the giant black spot on Jupiter's surface when the timing is right. But the size of the planet dwarfs the moon's shadow.
Jupiter's Eclipse In Live
Shadow of the Moon Over the Earth For Comparison
Why is Io's Shadow So Dark?
The reason behind the disparity between how the Earth's and Jupiter's moons look during an eclipse, is the distance of the Sun. The Sun relative to Jupiter's position in space seems much smaller than it does from Earth (duh the distance), but this causes the difference seen above.
The small view of the Sun from Jupiter makes Io appear 4 times as large as the center of our Solar System. So the penumbra (fuzzy outer layer of a shadow) is extremely thin by Jupiter, but quite wide when looking at the shadow of the Moon on Earth.
Super Rare Occurrence That For Earth Might Not Happen for Much Longer
A triple eclipse was spotted back in 2009, with Io Ganymede and Callisto (the moons of Jupiter) all managing to line up at just the right angle to each block out a part of the Sun's light.
But though we might be used to seeing the Earth's Moon cover up the sky with incredible eclipses, it has slowly been getting farther and farther away from the Sun, to the point that at some point, maybe in our lifetimes, the moon's shadow will no longer cover the Earth.