Uranus as seen by Voyager 2 in 1986 -- the only time a spacecraft has been near the planet.
In visible light, Uranus is a completely featureless, blue-green ball.
Only false-color infrared images show any features in its atmosphere.
(Voyager 2 Team, NASA, Planetary Photojournal)
The last image of Uranus taken by Voyager 2
Looking back at the planet, as the spacecraft headed toward Neptune.
(NASA, Voyager 2 Team, Planetary Photojournal)
False color image taken July 28, 1997 with Hubble Space Telescope
High contrast false color image with and without labels showing moons, rings, and direction of rotation
-- different colors represent brightness differences, not actual colors
The picture on the right was taken 90 minutes after the one on the left.
(E. Karkoschka (Univ. of Arizona Lunar & Planetary Lab), NASA, apod971126)
Montage of HST false-color images showing the 2007 "disappearance" of Uranus' rings
(NASA, ESA, and M. Showalter (SETI Institute)HubbleSite)
A false-color composite of infrared images of Uranus, taken two hours after its equator and ring system were edge-on relative to the Earth, on August 16, 2007. The next time this will happen is half of a Uranian orbit later, around 2050.
In visible light, the "surface" of Uranus is a completely featureless, blue-green ball of atmospheric gases; but in infrared wavelengths, bands of warmer or cooler clouds can be distinguished. Similarly, in visible light, the extremely dark rings of Uranus are not observable; but in infrared, the heat they absorb from the Sun makes them very slightly "visible". Even then, observing them requires special effort. In the image inset on the right, in which the ring system is faintly observable, the exposure is much longer than in the image on the left, in which the ring system is not observable (compare the glare from the inner moons to their much smaller images in the more normal exposure). Under normal circumstances, radiation from Uranus would completely swamp the image of the rings; but the long exposure was taken at a wavelength at which absorption by methane in the atmosphere of Uranus makes it even darker than the rings (the image of Uranus is a copy of the one in the left frame). (Image courtesy of ESO) |
High-contrast image of the rings and inner moons of Uranus in 1997.
As in the (2007) image above, the radiation from Uranus is dimmed by methane absorption.
(E. Lellouch & T. Encrenaz (Obs. Paris), J. Cuby, A. Jaunsen (ESO-Chile),
VLT Antu Telescope, European Southern Observatory, Chile, apod030115)
Close-up of the rings of Uranus, taken during the Voyager 2 flyby.
(NASA, Voyager 2 Team, Planetary Photojournal)
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