This is a Hubble Space Telescope image of the geologically active trailing hemisphere of the Jovian moon lo. The ultraviolet light image as taken with the European Space Agency's Faint Object Camera on March 15, 1992, when lo was 414 million miles from Earth. No larger than Earth's moon, lo is so far away it is at the resolution limit of ground-based telescopes, so surface features cannot be distinguished. HST resolves features as small as 150 miles across. This level of detail is only surpassed by the Voyager probes which flew within several hundred thousand miles of lo in 1979. lo's surface looks remarkably different in ultraviolet light than it does in visible light. Regions which look bright in visible light are dark in UV. The most likely explanation is that large areas of lo are covered with a sulfur dioxide frost. Because sulfur dioxide is a strong absorber of UV radiation, sulfur dioxide-rich areas are dark in the UV though they are bright in visible light. Technical Information: lo north is 123 degrees and east 33 degrees counterclockwise from the top of the print. The diameter of the satellite is 1 .l arc seconds equivalent to a diameter of 2170 miles. Resolution is 22 milliarcsec picture elements (pixels) corresponding to 43 miles per pixel on lo's surface.
Credits
Credit: Francesco Paresce (ESA/ STScI) Paola Sartoretti, University of Padova| About The Object | |
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| Object Name | Io, Jupiter |
| About The Object | |
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| Object Name | A name or catalog number that astronomers use to identify an astronomical object. |
| Object Description | The type of astronomical object. |
| R.A. Position | Right ascension – analogous to longitude – is one component of an object's position. |
| Dec. Position | Declination – analogous to latitude – is one component of an object's position. |
| Constellation | One of 88 recognized regions of the celestial sphere in which the object appears. |
| Distance | The physical distance from Earth to the astronomical object. Distances within our solar system are usually measured in Astronomical Units (AU). Distances between stars are usually measured in light-years. Interstellar distances can also be measured in parsecs. |
| Dimensions | The physical size of the object or the apparent angle it subtends on the sky. |
| About The Data | |
| Data Description |
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| Instrument | The science instrument used to produce the data. |
| Exposure Dates | The date(s) that the telescope made its observations and the total exposure time. |
| Filters | The camera filters that were used in the science observations. |
| About The Image | |
| Image Credit | The primary individuals and institutions responsible for the content. |
| Publication Date | The date and time the release content became public. |
| Color Info | A brief description of the methods used to convert telescope data into the color image being presented. |
| Orientation | The rotation of the image on the sky with respect to the north pole of the celestial sphere. |
