A Volcano on a Moon of Jupiter


io_lokiLoki Patera is the largest volcanic depression on Jupiter’s moon Io, 202 km in diameter. It contains an active lava lake, with an episodically overturning crust. Voyager 1 took this composite picture of Io showing an active plume from Loki on the moon’s limb. The images that make up this mosaic were taken from an average distance of approximately 490,000 km.

Image Credit: NASA

Approaching Neptune and Triton


This montage of images taken by Voyager 2 shows Neptune as it would appear from a spacecraft approaching Triton, Neptune’s largest moon. (Click on the picture to embiggen.) The eroded south polar cap of Triton is shown at the bottom of Triton’s image. Cryovolcanic terrain is at the upper right, and the as-yet unexplained “cantaloupe terrain” is at the upper left. Voyager 2 flew by Triton and Neptune in 1989.

Image Credit: NASA

Double Crescent


The Voyager 2 spacecraft camera captured Neptune and Triton together in crescent phase as it passed by in 1989. This picture of the gas giant and its cloudy moon was taken from behind the planet just after closest approach. It could not have been taken from Earth because Neptune never shows a crescent phase to sunward Earth; the sun always fully illuminates Neptune from our point of view. The unusual vantage point robs Neptune of its familiar blue color because the sunlight seen from behind the planet is scattered forward and is reddened like the setting Sun.

Image Credit: NASA/Voyager 2

You Are Here


This image of the Earth, called Pale Blue Dot, is a part of a family portrait of the solar system taken by Voyager 1. The spacecraft took 60 frames for a mosaic of the solar system looking back from a distance of over 4 billion miles from Earth. From that distance Earth is a tiny point of light, a crescent only 0.12 pixel in size. At the time its picture was taken, Earth happen to lie right in the center of one of the scattered light rays resulting from taking the image near the sun. This enlarged image of the Earth was taken through three color filters—violet, blue and green—and recombined to produce the color image. The background noise in the image is an artifact resulting from the high magnification.

Image Credit: NASA/JPL