Photos of Neptune, The Mysterious Blue Planet

These four Hubble images of Neptune were taken with the Wide Field Camera 3 on June 25-26, 2011, during the planet's 16-hour rotation. The snapshots were taken at roughly four-hour intervals, offering a full view of the planet. The images reveal high-altitude clouds in the northern and southern hemispheres. The clouds are composed of methane ice crystals.

A shot of faraway Neptune in infrared light, captured using the adaptive optics system at Hawaii's Keck Observatory.

On June 25, 2011, Neptune arrived at the same location in space where it was discovered 165 years earlier. To commemorate the event, NASA's Hubble Space Telescope took "anniversary pictures" of the blue-green giant planet.

This shot, taken in infrared light using the adaptive optics system at Hawaii's Keck Observatory, shows Neptune and its moon Triton (lower right).

A color image composed of exposures made through three color filters shows the disk of Neptune, revealing clouds in its atmosphere. Forty-eight individual images from a single filter were brightened to reveal the very faint moons and composited with the color image. Triton, in the lower left corner, is the brightest of the moons seen in these images, farthest from the planet, and moves in a counter-clockwise sense in this view.

Neptune's position in the sky is plotted on this star map, along with the 1846 predicted positions of its location, and where it was eventually discovered. The blue planet resides in the constellation Aquarius for the rest of 2011.

New measurements performed by the European Space Agency's Herschel infrared space telescope indicate that a comet may have hit Neptune, the outer-most planet in our solar system, two centuries ago.

The limb of Neptune arcs into darkness in this view of the planet's south pole taken by NASA's Voyager 2 spacecraft after it flew by the planet in 1989.

Take a look inside Neptune, the eighth planet from the Sun and has a thick atmosphere and the fastest winds in the solar system.

In this false color image of Neptune, objects that are deep in the atmosphere are blue, while those at higher altitudes are white. The image was taken by Voyager 2's wide-angle camera through an orange filter and two different methane filters. Light at methane wavelengths is mostly absorbed in the deeper atmosphere. The bright, white feature is a high altitude cloud just south of the Great Dark Spot. The hard, sharp inner boundary within the bright cloud is an artifact of computer processing on Earth.

Other, smaller clouds associated with the Great Dark Spot are white or pink, and are also at high altitudes. Neptune's limb looks reddish because Voyager 2 is viewing it tangentially, and the sunlight is scattered back to space before it can be absorbed by the methane.

A long, narrow band of high altitude clouds near the top of the image is located at 25 degrees north latitude, and faint hazes mark the equator and polar regions.

This color photo of Neptune's largest moon Triton was obtained by NASA's Voyager 2 probe on Aug. 24, 1989, from 330,000 miles away. The resolution is about 6.2 miles, sufficient to begin to show topographic detail.

Original Caption Released with Image: This wide-angle Voyager 2 image, taken through the camera's clear filter, is the first to show Neptune's rings in detail. The two main rings, about 53,000 km (33,000 miles) and 63,000 km (39,000 miles) from Neptune, are 5 to 10 times brighter than in earlier images. The difference is due to lighting and viewing geometry. In approach images, the rings were seen in light scattered backward toward the spacecraft at a 15-degree phase angle. However, this image was taken at a 135-degree phase angle as Voyager left the planet. That geometry is ideal for detecting microscopic particles that forward-scatter light preferentially. The fact that Neptune's rings are so much brighter at that angle means the particle-size distribution is quite different from most of Uranus' and Saturn's rings, which contain fewer dust-size grains. However, a few components of the Saturnian and Uranian ring systems exhibit forward-scattering behavior: The F ring and the Encke Gap ringlet at Saturn, and 1986U1R at Uranus. They are also narrow, clumpy ringlets with kinks, and are associated with nearby moonlets too small to detect directly. In this image, the main clumpy arc, composed of three features each about 6 to 8 degrees long, is clearly seen. This image was obtained when Voyager was 1.1 million km (683,000 miles) from Neptune. Exposure time was 111seconds. The Voyager Mission is conducted by JPL for NASA's Office of Space Science and Applications. Image Credit: NASA/JPL Image Addition Date: 1999-08-08

Thermal images show temperatures near the top of Neptune's troposphere (upper left image), with the hottest temperatures found at the south pole (see graphic, upper right). The lower two images show temperatures at higher altitudes in Neptune's stratosphere, or lower atmosphere.

An artist's conception of Triton and its binary companion as they approach Neptune. This encounter facilitated Triton’s capture to an inclined retrograde orbit around Neptune, an event that catastrophically altered the Neptune satellite system.

These images of the south pole of Neptune show the two spots created from a single storm converge back into one as seen by astronomers in July 2007.

This view of the volcanic plains of Neptune's moon Triton was made from topographic mapping of images obtained by NASA's Voyager 2 spacecraft during its August 1989 flyby.

This image of Neptune was taken by Voyager 2's wide-angle camera when the spacecraft was 590,000 km (370,000 miles) from the planet. The image has been processed to obtain true color balance. Additional processing was used to suppress surface brightness of the white clouds. The processing allows both the clouds' structure in the dark regions near the pole and the bright clouds east of the Great Dark Spot to be reproduced in this color photograph. Small trails of similar clouds trending east to west and large scale structure east of the Great Dark Spot all suggest that waves are present in the atmosphere and play a large role in the type of clouds that are visible.

This photograph shows the last face on view of the Great Dark Spot that Voyager will make with the narrow angle camera. The image was shuttered 45 hours before closest approach at a distance of 2.8 million kilometers (1.7 million miles). The smallest structures that can be seen are of an order of 50 kilometers (31 miles)

NASA's Hubble Space Telescope discovered a new great dark spot, located in the northern hemisphere of the planet Neptune. Because the planet's northern hemisphere is now tilted away from Earth, the new feature appears near the limb of the planet. The spot is a near mirror-image to a similar southern hemisphere dark spot that was discovered in 1989 by the Voyager 2 probe. In 1994, Hubble showed that the southern dark spot had disappeared.

This Voyager 2 high resolution color image, taken 2 hours before closest approach, provides obvious evidence of vertical relief in Neptune's bright cloud streaks. These clouds were observed at a latitude of 29 degrees north near Neptune's east terminator. The linear cloud forms are stretched approximately along lines of constant latitude and the sun is toward the lower left. The bright sides of the clouds which face the sun are brighter than the surrounding cloud deck because they are more directly exposed to the sun. Shadows can be seen on the side opposite the sun

An artist's concept of a craggy piece of Solar System debris that belongs to a class of bodies called trans-Neptunian objects. Astronomers culling the data archives of NASA's Hubble Space Telescope have added 14 new TNOs to the catalog.

Neptune’s winds travel at more than 1,500 mph, and are the fastest planetary winds in the solar system.