Dark Spots on Neptune
Credit:
Voyager 2 Team,
NASA
Neptune has spots.
The Solar System's outermost gas giant shows a
nearly uniform blue hue created by small amounts of
methane drifting in a thick atmosphere of
nearly colorless
hydrogen and
helium.
Dark spots do appear, however, that are
anti-cyclones:
large high-pressure systems that swirl in
Neptune's cold cloud tops.
Two dark spots are visible in the
above picture taken by the robot
Voyager 2 spacecraft in 1989: an
Earth-sized
Great Dark Spot located on the far left, and
Dark Spot 2 located near bottom.
A bright cloud dubbed
Scooter accompanies the Great Dark Spot.
Recent computer simulations indicate that
scooters are methane clouds that might commonly
be found near dark spots.
Subsequent
images of
Neptune by the
Hubble Space Telescope
in 1994 indicated that both of these
dark spots had dissipated, but
another had been created.