Category Archives: Image

Sliver of Saturn


Although only a sliver of Saturn’s sunlit face is visible in this view, the mighty gas giant planet still dominates the view.

From this vantage point just beneath the ring plane, the dense B ring becomes dark and essentially opaque, letting almost no light pass through. But some light reflected by the planet passes through the less dense A ring, which appears above the B ring in this photo. The C ring, silhouetted just below the B ring, lets almost all of Saturn’s reflected light pass right through it, as if it were barely there at all. The F ring appears as a bright arc in this image, which is visible against both the backdrop of Saturn and the dark sky. (For a diagram showing the names and positions of the rings see Expanse of Ice .)

This view looks toward the unilluminated side of the rings from about 7 degrees below the ring plane. The image was taken in green light with the Cassini spacecraft wide-angle camera on Jan. 18, 2017.

The view was acquired at a distance of approximately 630,000 miles (1 million kilometers) from Saturn. Image scale is 38 miles (61 kilometers) per pixel.

The Cassini mission is a cooperative project of NASA, ESA (the European Space Agency) and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA’s Science Mission Directorate, Washington. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging operations center is based at the Space Science Institute in Boulder, Colorado.

The Splitting of the Dunes


The mound in the center of this Mars Reconnaissance Orbiter (MRO) image appears to have blocked the path of the dunes as they marched south (north is to the left in this image) across the scene. Many of these transverse dunes have slipfaces that face south, although in some cases, it’s hard to tell for certain. Smaller dunes run perpendicular to some of the larger-scale dunes, probably indicating a shift in wind directions in this area.

Although it might be hard to tell, this group of dunes is very near the central pit of a 35-kilometer-wide impact crater. Data from other instruments indicate the presence of clay-like materials in the rock exposed in the central pit.

This image was acquired by the High Resolution Imaging Science Experiment (HiRISE) instrument aboard MRO on April 27, 2009, at 15:16 local Mars time. It is a stereo pair with image ESP_013319_1685.

The map is projected here at a scale of 50 centimeters (9.8 inches) per pixel. [The original image scale is 52 centimeters (20.5 inches) per pixel (with 2 x 2 binning); objects on the order of 156 centimeters (61.4 inches) across are resolved.] North is up.

The University of Arizona, Tucson, operates HiRISE, which was built by Ball Aerospace & Technologies Corp., Boulder, Colo. NASA’s Jet Propulsion Laboratory, a division of Caltech in Pasadena, California, manages the Mars Reconnaissance Orbiter Project for NASA’s Science Mission Directorate, Washington.

Space Station View of Mount Etna Erupting


The Expedition 50 crew aboard the International Space Station had a nighttime view from orbit of Europe’s most active volcano, Mount Etna, erupting on March 19, 2017. Astronaut Thomas Pesquet of the European Space Agency captured this image and shared it with his social media followers, writing, “Mount Etna, in Sicily. The volcano is currently erupting and the molten lava is visible from space, at night! (the red lines on the left).”

The Big One


Mimas’ gigantic crater Herschel lies near the moon’s limb in this Cassini view.

A big enough impact could potentially break up a moon. Luckily for Mimas, whatever created Herschel was not quite big enough to cause that level of disruption.

When large impacts happen, they deliver tremendous amounts of energy — sometimes enough to cause global destruction. Even impacts that are not catastrophic can leave enormous, near-permanent scars on bodies like Mimas (246 miles or 396 kilometers across).

This view looks toward the anti-Saturn hemisphere of Mimas. North on Mimas is up and rotated 32 degrees to the left. The image was taken in visible light with the Cassini spacecraft narrow-angle camera on Nov. 19, 2016.

The view was acquired at a distance of approximately 53,000 miles (85,000 kilometers) from Mimas. Image scale is 1,677 feet (511 meters) per pixel.

The Cassini mission is a cooperative project of NASA, ESA (the European Space Agency) and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA’s Science Mission Directorate, Washington. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging operations center is based at the Space Science Institute in Boulder, Colorado.

The Cassini mission is a cooperative project of NASA, ESA (the European Space Agency) and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA’s Science Mission Directorate, Washington. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging operations center is based at the Space Science Institute in Boulder, Colorado.

Hubble Homes In on a Hypergiant’s Home


This beautiful Hubble image reveals a young super star cluster known as Westerlund 1, only 15,000 light-years away in our Milky Way neighborhood, yet home to one of the largest stars ever discovered.

Stars are classified according to their spectral type, surface temperature, and luminosity. While studying and classifying the cluster’s constituent stars, astronomers discovered that Westerlund 1 is home to an enormous star. Originally named Westerlund 1-26, this monster star is a red supergiant (although sometimes classified as a hypergiant) with a radius over 1,500 times that of our sun. If Westerlund 1-26 were placed where our sun is in our solar system, it would extend out beyond the orbit of Jupiter.

Most of Westerlund 1’s stars are thought to have formed in the same burst of activity, meaning that they have similar ages and compositions. The cluster is relatively young in astronomical terms —at around three million years old it is a baby compared to our own sun, which is some 4.6 billion years old.

Images of the Sun From the GOES-16 Satellite


These images of the sun were captured at the same time on January 29, 2017 by the six channels on the Solar Ultraviolet Imager or SUVI instrument aboard NOAA’s GOES-16 satellite. They show a large coronal hole in the sun’s southern hemisphere. Data from SUVI will provide an estimation of coronal plasma temperatures and emission measurements which are important to space weather forecasting.

SUVI is essential to understanding active areas on the sun, solar flares and eruptions that may lead to coronal mass ejections which may impact Earth. Depending on the magnitude of a particular eruption, a geomagnetic storm can result that is powerful enough to disturb Earth’s magnetic field. Such an event may impact power grids by tripping circuit breakers, disrupt communication and satellite data collection by causing short-wave radio interference and damage orbiting satellites and their electronics. SUVI will allow the NOAA Space Weather Prediction Center to provide early space weather warnings to electric power companies, telecommunication providers and satellite operators.

NASA successfully launched GOES-R at 6:42 p.m. EST on November 19, 2016 from Cape Canaveral Air Force Station in Florida. It was renamed GOES-16 when it achieved orbit. GOES-16 is now observing the planet from an equatorial view approximately 22,300 miles above the surface of the Earth.

Image Credit: NOAA

Hubble Rocks with a Heavy-Metal Home


This 10.5-billion-year-old globular cluster, NGC 6496, is home to heavy-metal stars of a celestial kind! The stars comprising this spectacular spherical cluster are enriched with much higher proportions of metals — elements heavier than hydrogen and helium are curiously known as metals in astronomy — than stars found in similar clusters.

A handful of these high-metallicity stars are also variable stars, meaning that their brightness fluctuates over time. NGC 6496 hosts a selection of long-period variables — giant pulsating stars whose brightness can take up to, and even over, a thousand days to change — and short-period eclipsing binaries, which dim when eclipsed by a stellar companion.

The nature of the variability of these stars can reveal important information about their mass, radius, luminosity, temperature, composition, and evolution, providing astronomers with measurements that would be difficult or even impossible to obtain through other methods.

NGC 6496 was discovered in 1826 by Scottish astronomer James Dunlop. The cluster resides at about 35,000 light-years away in the southern constellation of Scorpius (The Scorpion).

Image credit: ESA/Hubble & NASA, Acknowledgement: Judy Schmidt
Text credit: European Space Agency

Anticrepuscular Rays over Colorado


What’s happening over the horizon? Although the scene may appear somehow supernatural, nothing more unusual is occurring than a setting Sun and some well placed clouds. Pictured above are anticrepuscular rays. To understand them, start by picturing common crepuscular rays that are seen any time that sunlight pours though scattered clouds. Now although sunlight indeed travels along straight lines, the projections of these lines onto the spherical sky are great circles. Therefore, the crepuscular rays from a setting (or rising) sun will appear to re-converge on the other side of the sky. At the anti-solar point 180 degrees around from the Sun, they are referred to as anticrepuscular rays. Featured here is a particularly striking display of anticrepuscular rays photographed earlier this month in Westminster, Colorado, USA.

Up and Over


Cassini orbited in Saturn’s ring plane — around the planet’s equator — for most of 2015. This enabled a season of flybys of the planet’s icy moons, but did not allow for angled views of the rings and the planet’s poles, like this one. But in early 2016, the spacecraft began to increase its orbital inclination, climbing higher over the poles in preparation for the mission’s final spectacular orbits in 2017.

This view looks toward the sunlit side of the rings from about 16 degrees above the ring plane. The image was taken with the Cassini spacecraft wide-angle camera on Feb. 26 2016 using a spectral filter which preferentially admits wavelengths of near-infrared light centered at 752 nanometers.

The view was obtained at a distance of approximately 1.7 million miles (2.8 million kilometers) from Saturn. Image scale is 103 miles (165 kilometers) per pixel.

The Cassini mission is a cooperative project of NASA, ESA (the European Space Agency) and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA’s Science Mission Directorate, Washington. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging operations center is based at the Space Science Institute in Boulder, Colorado.

Credit: NASA/JPL-Caltech/Space Science Institute

Cirrus over Paris


What’s that over Paris? Cirrus. Typically, cirrus clouds appear white or gray when reflecting sunlight, can appear dark at sunset (or sunrise) against a better lit sky. Cirrus are among the highest types of clouds and are usually thin enough to see stars through. Cirrus clouds may form from moisture released above storm clouds and so may herald the arrival of a significant change in weather. Conversely, cirrus clouds have also been seen on Mars, Jupiter, Saturn, Titan, Uranus, and Neptune. The featured image was taken two days ago from a window in District 15, Paris, France, Earth. The brightly lit object on the lower right is, of course, the Eiffel Tower.