[Upper Left]
A visible-light image of the geologically active trailing hemisphere of the Jovian moon Io, taken on March 15 1992, when Io was' 414 million miles from Earth. HST resolves features as small a:s150 miles across.
[Upper Right]
An ultraviolet light (UV) picture of the same hemisphere show's Io's surface. Regions which look bright In visible light are dark in UV. The most likely explanation is that large areas of Io 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.
[Bottom Right]
An image of Io taken 13 years ago by the Voyager spacecraft at a distance of approximately 250,000 miles.
[Bottom Left]
A "synthetic" Voyager Image modified to match HST's resolution, due to the fact that HST is one thousand times farther from Io then Voyager was at closest approach. A direct comparison of the visual FOC visible light image with this synthetic Voyager image shows no change in the large scale distribution of surface materials in the 13 years which have elapsed between the two observations.
Credits
HST/FOC images: Francesco Paresce (ESAI STScI) Paola Sartoretti, University of PadovaVoyager Image: NASA
| About The Object | |
|---|---|
| Object Name | Io, Jupiter |
| About The Object | |
|---|---|
| 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 |
|
| 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. |
