A solar eclipse viewed from Earth reveals the sun's corona and you can only see the brightest stars from Earth.

Solar Eclipse on Earth

However a solar eclipse viewed from the moon would show the red ring around Earth.

Solar Eclipse on the Moon

I have not seen an image / video of what a solar eclipse would look like on one of Jupiter's Galilean moons.

How long would an eclipse last on these objects? How dark would it get? Which stars / planets would be visible with the naked eye? Could you still see the sun's corona during these eclipses?

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    $\begingroup$ Asking about Io and Jupiter is a bit like asking about ISS and Earth. Being in Earth's shadow in a low Earth orbit is not commonly called an eclipse; being in the Moon's shadow on Earth has its own word only because the Moon's and the Sun's apparent sizes seen from Earth are both rather small so that it is a rare, extraordinary situation. $\endgroup$ Oct 26, 2022 at 11:41
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    $\begingroup$ @Peter-ReinstateMonica Of course we have a special word for the really common situation of being in the Earth's shadow: "night". $\endgroup$ Oct 26, 2022 at 13:23
  • $\begingroup$ @user3067860 Point taken. $\endgroup$ Oct 26, 2022 at 13:25
  • $\begingroup$ I'm surprised we see so much light and corona when Earth eclipses the Sun, since the apparent size of Earth from the Moon is 4x the size of the Sun. Eclipses of the Sun by the Moon are so spectactular because they're almost the same sizes. $\endgroup$
    – Barmar
    Oct 26, 2022 at 15:31

1 Answer 1


It depends what moon you’re talking about because each of the moons have a different distance from Jupiter, but I assume you mean Io, as it is in your title.

How long would eclipses last on Io?

Totality on Earth can only last up to about 7 minutes 31 seconds because of the moon’s small size, but because of Jupiter’s large size and close proximity to Io, totality on Io may last up to 2 hours.

How dark would it get?

At Jupiter, the sunlight is only 3.7% of what Earth gets. So already by itself, the sky is much darker than it would be on Earth. There’s no definite answer for this, but since Jupiter is super big, it will probably block out nearly all of the light from the sun, which is added with the fact that Io is really close to the giant, so Jupiter will appear larger than it would appear for example, Europa.

How many stars would you see?

Io also has nearly no atmosphere, only an extremely thin layer of sulfur dioxide. This means that the sky would be similar to the vastness of space, with many stars visible. Jupiter however, will cover a considerable amount of space in the sky. There would also be Jupiter’s other moons visible too. If at the right time, Saturn will appear bright in the sky, with Uranus in the background, visible to the unaided eye, but very dim.

Would you still be able to see the sun’s corona?

No, most likely not. The corona from the sun only radiates about five million miles out, and combined with the sun’s tiny size from Io and Jupiter’s gargantuan size puts the corona well behind Jupiter during the eclipse.

Of course, we are talking about an eclipse where Jupiter perfectly occulates the sun, and not some partial eclipse from Jupiter.

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    $\begingroup$ Presumably you'd be able to see the corona in the moments after the Sun was occulted, even if you couldn't see it for the entire eclipse. $\endgroup$ Oct 26, 2022 at 12:02
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    $\begingroup$ Also, the fact that Jupiter is entirely gaseous would probably lead to significant reddening of the sunlight during the first moments of occultation — not unlike the "red ring" in the OP's image of an eclipse on the Moon, but more localized near Jupiter's limb. $\endgroup$ Oct 26, 2022 at 12:04

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