Voyager's Neptune
Composite Image Credit &
Copyright:
Assembly/Processing -
Rolf Olsen,
Data - Voyager 2,
NASA
Planetary Data System
Explanation:
Cruising through the outer solar system, the Voyager 2
spacecraft made its closest
approach
to Neptune on August 25, 1989,
the only spacecraft to visit the most distant
ice giant planet.
Based on the images recorded during its close encounter
and in the following days,
this inspired composited scene covers the
dim outer planet, largest
moon Triton, and faint system of rings.
From just beyond Neptune's orbit, the interplanetary perspective
looks back toward the Sun, capturing
the planet and Triton as thin
sunlit crescents.
Cirrus clouds and a dark band
circle Neptune's south polar region,
with a cloudy vortex above the pole
itself.
Parts of the
very
faint ring system along with
the three bright ring arcs were first imaged by Voyager during the
fly-by, though the faintest segments are modeled in this
composited picture.
Spanning 7.5 degrees, the background starfield is composed
from sky survey data centered on the constellation Camelopardalis,
corresponding to the outbound Voyager's view of the
magnificent Neptunian system.
Opportunity's Mars Analemma
Image Credit:
NASA/JPL/Cornell/ASU/TAMU
Explanation:
Staring up into the martian sky, the
Opportunity rover
captured an image at 11:02 AM local mean
time nearly every 3rd sol, or martian day, for 1 martian year.
Of course, the result is this
martian analemma,
a curve tracing the Sun's motion through the
sky in the course of a year (668 sols)
on
the Red Planet.
Spanning Earth dates from July, 16, 2006 to June 2, 2008 the images
are shown composited in
this zenith-centered, fisheye projection.
North is at the top surrounded by a
panoramic sky and landscape made in
late 2007 from inside Victoria crater.
The tinted martian sky is blacked
out around the analemma images to clearly show the Sun's positions.
Unlike Earth's figure-8-shaped analemma,
Mars'
analemma is pear-shaped, because of its similar axial tilt
but more elliptical orbit.
When Mars is farther from the Sun, the Sun progresses slowly in
the martian sky creating the pointy top of the curve.
When close to the Sun and moving quickly, the apparent solar motion
is stretched into the rounded bottom.
For several sols some of the frames are missing due to
rover operations and dust storms.
Hubble's Jupiter and the Amazing Shrinking Great Red Spot
Credit:
NASA,
ESA, and
Amy Simon (Goddard Space Flight
Center)
et al.
Explanation:
Gas
giant Jupiter is the solar system's
largest world with about 320 times the mass
of planet Earth.
It's also known for a giant swirling storm system,
the
Great
Red Spot, featured in this
sharp Hubble image from April 21.
Nestled between Jupiter-girdling cloud bands, the Great Red Spot
itself could still easily swallow Earth, but lately it has
been shrinking.
The
most recent Hubble observations measure the spot to be
about 10,250 miles (16,500 kilometers) across.
That's the smallest ever measured by Hubble
and particularly dramatic when compared to 14,500 miles measured by
the Voyager 1
and 2 flybys in 1979, and historic telescopic observations
from the 1800s indicating a width of about 25,500 miles on its long
axis.
Current indications are that the rate of shrinking is increasing for the
long-lived Great Red Spot.
Jupiter's Great Red Spot from Voyager 1
Image Credit:
NASA,
JPL;
Digital processing:
Björn Jónsson
(IAAA)
Explanation:
What will become of Jupiter's Great Red Spot?
Recorded as shrinking since the 1930s, the rate of the
Great Red Spot's size appears to have accelerated just in the past few years.
A hurricane larger than Earth, the
Great Red Spot has been
raging
at least as long as telescopes could see it.
Like most astronomical phenomena, the
Great Red Spot was neither predicted nor immediately understood after its discovery.
Although small eddies that feed into the
storm system seem to play a role, a more full understanding of the
gigantic storm cloud
remains a topic of continued research, and may result in a
better understanding of weather here on Earth.
The
above image
is a digital enhancement of an image of Jupiter taken in 1979 by the
Voyager 1 spacecraft as it zoomed by the Solar System's largest planet.
NASA's
Juno spacecraft
is currently heading
toward Jupiter
and will arrive in 2016.
