page_title: Extraterrestrial sky
section_title: Saturn
hierarchical_section_title: Extraterrestrial sky / Saturn
caption_attribution_description: English: In this rare image taken on July 19, 2013, the wide-angle camera on NASA's Cassini spacecraft has captured Saturn's rings and our planet Earth and its moon in the same frame. It is only one footprint in a mosaic of 33 footprints covering the entire Saturn ring system (including Saturn itself). At each footprint, images were taken in different spectral filters for a total of 323 images: some were taken for scientific purposes and some to produce a natural color mosaic. This is the only wide-angle footprint that has the Earth-moon system in it. The dark side of Saturn, its bright limb, the main rings, the F ring, and the G and E rings are clearly seen; the limb of Saturn and the F ring are overexposed. The "breaks" in the brightness of Saturn's limb are due to the shadows of the rings on the globe of Saturn, preventing sunlight from shining through the atmosphere in those regions. The E and G rings have been brightened for better visibility. Earth, which is 898 million miles (1.44 billion kilometers) away in this image, appears as a blue dot at center right; the moon can be seen as a fainter protrusion off its right side. An arrow indicates their location in the annotated version. (The two are clearly seen as separate objects in the accompanying narrow angle frame: PIA14949.) The other bright dots nearby are stars. This is only the third time ever that Earth has been imaged from the outer solar system. The acquisition of this image, along with the accompanying composite narrow- and wide-angle image of Earth and the moon and the full mosaic from which both are taken, marked the first time that inhabitants of Earth knew in advance that their planet was being imaged. That opportunity allowed people around the world to join together in social events to celebrate the occasion. This view looks toward the unilluminated side of the rings from about 20 degrees below the ring plane. Images taken using red, green and blue spectral filters were combined to create this natural color view. The images were obtained with the Cassini spacecraft wide-angle camera on July 19, 2013 at a distance of approximately 753,000 miles (1.212 million kilometers) from Saturn, and approximately 898.414 million miles (1.445858 billion kilometers) from Earth. Image scale on Saturn is 43 miles (69 kilometers) per pixel; image scale on the Earth is 53,820 miles (86,620 kilometers) per pixel. The illuminated areas of neither Earth nor the Moon are resolved here. Consequently, the size of each "dot" is the same size that a point of light of comparable brightness would have in the wide-angle camera.
context_page_description: In astronomy, an extraterrestrial sky is a view of outer space from the surface of a planet other than Earth.
  The only extraterrestrial sky that has been directly observed and photographed by astronauts is that of the Moon. The skies of Venus, Mars and Titan have been observed by space probes designed to land on the surface and send images back to Earth.
  Extraterrestrial skies seem to vary because of a number of reasons. An extraterrestrial atmosphere, if present, has a large bearing on visible characteristics. The atmosphere's density and chemical composition can contribute to differences in color, opacity and the presence of clouds. Astronomical objects may also be visible and can include natural satellites, rings, star systems and nebulas and other planetary system bodies.
  For skies that have not been directly or indirectly observed, their appearance can be simulated based on known factors, such as the position of astronomical objects relative to the surface and atmospheric composition.
context_section_description: The sky in the upper reaches of Saturn's atmosphere is blue, but the predominant color of its cloud decks suggests that it may be yellowish further down. The rings of Saturn are almost certainly visible from the upper reaches of its atmosphere. The rings are so thin that from a position on Saturn's equator, they would be almost invisible. However, from anywhere else on the planet, they could be seen as a spectacular arc stretching across half the celestial hemisphere.
  Saturn's moons would not look particularly impressive in its sky, as most are fairly small, and the largest are a long way from the planet. Even Titan, the largest moon of Saturn, appears only half the size of Earth's moon. In fact, Titan is the dimmest of Saturn's large moons due to its great distance and dimness; Mimas, Enceladus, Tethys, Dione, and Rhea are all brighter. Most of the inner moons would appear as bright, star-like points (with the exception of Janus, although most would shine brighter than any star. None of the outer moons would be visible except Phoebe which would be very dim.
caption: Earth and Moon (bottom-right) from Saturn (Cassini; July 2013)
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