Io Transit of Jupiter

The three snapshots of the volcanic moon rounding Jupiter were taken over a 1.8-hour time span. Io is roughly the size of Earth's moon but 2, 000 times farther away. In two of the images, Io appears to be skimming Jupiter's cloud tops, but it's actually 310, 000 miles (500, 000 kilometers) away. Io zips around Jupiter in 1.8 days, whereas the moon circles Earth every 28 days.

The conspicuous black spot on Jupiter is Io's shadow and is about the size of the moon itself (2, 262 miles or 3, 640 kilometers across). This shadow sails across the face of Jupiter at 38, 000 mph (17 kilometers per second). The smallest details visible on Io and Jupiter measure 93 miles (150 kilometers) across, or about the size of Connecticut.


J. Spencer (Lowell Observatory) and NASA/ESA

About the Image

NASA press release
NASA caption
Release date:20 April 1999, 06:00
Size:716 x 741 px

About the Object

Name:Io, Jupiter
Type:Solar System : Planet : Type : Gas Giant
Solar System : Planet : Satellite
Category:Solar System

Image Formats

Large JPEG
123.1 KB
Screensize JPEG
157.0 KB

Colours & filters

410 nm Hubble Space Telescope
340 nm Hubble Space Telescope

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