NASA Cassini Image: Looking beyond Saturn to view Uranus

This view from NASA's Cassini spacecraft features a blue planet, but unlike the view from July 19, 2013 (PIA17172 The Day the Earth Smiled) that featured our home planet, this blue orb is Uranus, imaged by Cassini for the first time.

Credit: NASA /JPL-Caltech /Space Science Institute

Uranus is a pale blue in this natural colour image because its visible atmosphere contains methane gas and few aerosols or clouds.

Methane on Uranus and its sapphire-coloured sibling, Neptune, absorbs red wavelengths of incoming sunlight, but allows blue wavelengths to escape back into space, resulting in the predominantly bluish color seen here.

Cassini imaging scientists combined red, green and blue spectral filter images to create a final image that represents what human eyes might see from the vantage point of the spacecraft.

Uranus

Uranus has been brightened by a factor of 4.5 to make it more easily visible. The outer portion of Saturn's A ring, seen at bottom right, has been brightened by a factor of two.

The bright ring cutting across the image center is Saturn's narrow F ring.

Uranus was approximately 28.6 astronomical units from Cassini and Saturn when this view was obtained.

An astronomical unit is the average distance from Earth to the sun, equal to 93,000,000 miles (150,000,000 kilometers).

Neptune

The view was acquired by the Cassini narrow-angle camera at a distance of approximately 614,300 miles (988,600 kilometers) from Saturn on April 11, 2014.

Image scale at Uranus is approximately 16,000 miles (25,700 kilometers) per pixel.

Image scale at Saturn's rings is approximately 4 miles (6 kilometers) per pixel.

In the image, the disk of Uranus is just barely resolved.

The solar phase angle at Uranus, seen from Cassini, is 11.9 degrees.