Active Dune Field on Mars
Nili Patera is one of the most active dune fields on Mars. As such, it is continuously monitored with the HiRISE (High Resolution Imaging Science Experiment) camera, a science instrument aboard NASA's Mars Reconnaissance Orbiter, with a new image acquired about every six weeks.
By monitoring the sand dune changes, we can determine how winds vary seasonally and year-to-year. This observation is one of the more recent Nili images, acquired on March 1, 2014. Compared to an image acquired on Nov. 22, 2012, changes are obvious. The ripples on the dunes have moved, as well some of the dune boundaries, such as the one at upper left. New landslides on the central dune's lee face are apparent.
Such changes, in just 16 months (and finer scale changes have been seen in just a couple of weeks), demonstrate the effectiveness of wind in modifying the Martian landscape.
HiRISE is one of six instruments on NASA's Mars Reconnaissance Orbiter. The University of Arizona, Tucson, operates the orbiter's HiRISE camera, which was built by Ball Aerospace & Technologies Corp., Boulder, Colo. NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Mars Reconnaissance Orbiter Project for the NASA Science Mission Directorate, Washington.
Image Credit: NASA/JPL-Caltech/Univ. of Arizona
Caption: Nathan Bridges
Caption: Nathan Bridges
Volcanic Plume Over Southern Atlantic Ocean Revealed Through False-Color Imagery
The South Sandwich Islands, in the far southern Atlantic Ocean, are often shrouded with thick cloud, making it difficult to view the region from space. Sometimes, however, the use of false-color imagery can be used to reveal events that would otherwise be obscured under cloud cover.
The Moderate Resolution Imaging Spectroradiometer (MODIS) aboard NASA’s Aqua satellite flew over the South Sandwich Islands on April 19, 2014 and acquired this false-color image of the cloudy scene.
This false-color image uses a combination of non-visible (middle infrared and infrared) and visible (red) light captured in bands 7, 2, and 1, respectively, to distinguish clouds from snow and ice. Here the ice-covered islands appear bright turquoise, the clouds light turquoise and the water in the ocean appears deep black. Because the volcanic plume is a moist mixture of gas and ash, it reflects all three forms of light relatively well, so it appears nearly white.
In the north of this image, a thin plume of white rises from the volcano on Zavodovski island, the northernmost of the South Sandwich Islands and streams to the northeast. Further south, a wider white plume can be seen blowing across the Atlantic Ocean. This plume rises from the Mount Michael volcano, which is a young and frequently active stratovolcano located on Saunders Island, near the center of the South Sandwich Island chain.
The white plume from Mount Michael forms a chain of swirling eddies as it blows to the northeast. To the south, similar eddies can be seen behind three other islands. These are known as Von Kármán vortices. These vortices can form nearly anywhere that fluid flow is disturbed by an object. Because the atmosphere behaves like a fluid, when streaming air hits a blunt object, such as a mountain peak, the wind is forced around the object. The disturbance in the flow of the wind propagates downstream in a double row of vortices that alternate their direction of rotation, much like the eddies seen behind a pier in a river as water rushes past.
Image Credit: Jeff Schmaltz/MODIS Land Rapid Response Team, NASA GSFC
Hubble's Messier 5
"Beautiful Nebula discovered between the Balance [Libra] & the Serpent [Serpens] ..." begins the description of the 5th entry in 18th century astronomer Charles Messier's famous catalog of nebulae and star clusters. Though it appeared to Messier to be fuzzy and round and without stars, Messier 5 (M5) is now known to be a globular star cluster, 100,000 stars or more, bound by gravity and packed into a region around 165 light-years in diameter. It lies some 25,000 light-years away. Roaming the halo of our galaxy, globular star clusters are ancient members of the Milky Way. M5 is one of the oldest globulars, its stars estimated to be nearly 13 billion years old. The beautiful star cluster is a popular target for Earthbound telescopes. Of course, deployed in low Earth orbit on April 25, 1990, the Hubble Space Telescope has also captured its own stunning close-up view that spans about 20 light-years near the central region of M5. Even close to its dense core at the left, the cluster's aging red and blue giant stars and rejuvenated blue stragglers stand out in yellow and blue hues in the sharp color image.
Image Credit: NASA, Hubble Space Telescope, ESA
Hubble Space Telescope Reaches Orbit
On April 24, 1990, the Hubble Space Telescope was launched aboard Space Shuttle Discovery on the STS-31 mission. The mission featured the deployment of Hubble, the first of NASA's Great Observatories to reach orbit. STS-31 was the tenth launch of the shuttle Discovery. On board were astronauts Charles F. Bolden (pilot, now NASA Administrator), Steven A. Hawley (mission specialist), Loren J. Shriver (commander), Bruce McCandless (mission specialist) and Kathryn D. Sullivan (mission specialist, now NOAA Administrator).
In this April 25, 1990 photograph taken with a handheld Hasselblad camera, most of the giant Hubble Space Telescope can be seen as it is suspended in space by Discovery's Remote Manipulator System (RMS) following the deployment of part of its solar panels and antennae. This was among the first photos NASA released on April 30 from the five-day STS-31 mission.
Image Credit: NASA
Earth Science Radar Imaging Mission Travels to Central and South America
This photo of volcanoes in Guatemala was taken from NASA's C-20A aircraft during a four-week Earth science radar imaging mission deployment over Central and South America. The conical volcano in the center is "Volcan de Agua." The two volcanoes behind it are, right to left, "Volcan de Fuego" and "Acatenango." "Volcan de Pacaya" is in the foreground.
The radar imaging mission got underway in early April when the C-20A departed its base in Palmdale, Calif., to collect data over targets in the Gulf Coast area of the southeastern United States. The aircraft, a modified Gulfstream III, is carrying NASA's Uninhabited Aerial Vehicle Synthetic Aperture Radar (UAVSAR) instrument in a specialized pod. Developed by NASA's Jet Propulsion Laboratory in Pasadena, Calif., UAVSAR measures ground deformation over large areas to a precision of 0.04 to 0.2 inches (0.1 to 0.5 centimeters).
The mission schedule calls for the aircraft to make stops in 10 international and U.S. locations, including the Gulf Coast. Research during the deployment is covering a variety of topics, including volcanoes, glaciers, forest structure, levees, and subsidence. It is also providing vegetation data sets for satellite algorithm development. The volcanoes of Central and South America are of interest because of the hazard they pose to nearby population centers. A majority of the research will focus on gathering volcano deformation measurements, with many flight lines being repeats from previous deployments. Surface deformation often precedes other signs of renewed volcanic activity.
Image Credit: NASA/Stu Broce
SpaceX Dragon Grappled to Canadarm2
On Sunday, April 20, 2014, the Expedition 39 crew aboard the International Space Station welcomed nearly two-and-a-half tons of supplies and scientific payloads to the station with the arrival of the third SpaceX Dragon commercial cargo spacecraft. This image of SpaceX Dragon grappled by Canadarm2 was sent down by Flight Engineer Steve Swanson to Instagram with the message, "We have a Dragon. All is good."
With Dragon securely in the grasp of Canadarm2, the robotics officer at Mission Control remotely operated the arm to install the capsule to its port on the Earth-facing side of the Harmony module. Once Dragon was in place, Flight Engineer Rick Mastracchio monitored the Common Berthing Mechanism operations for first and second stage capture of the cargo ship, assuring that the vehicle was securely attached to the station with a hard mate. Second stage capture was completed at 10:06 a.m. EDT as the station flew 260 miles above Brazil.
Image Credit: NASA
Hubble Celebrates 24th Anniversary with Infrared Image of Nearby Star Factory
In celebration of the 24th anniversary of the launch of NASA's Hubble Space Telescope, astronomers have captured infrared-light images of a churning region of star birth 6,400 light-years away.
This colorful Hubble Space Telescope mosaic of a small portion of the Monkey Head Nebula unveils a collection of carved knots of gas and dust silhouetted against glowing gas. The cloud is sculpted by ultraviolet light eating into the cool hydrogen gas.
Image Credit: NASA, ESA, and the Hubble Heritage Team (STScI/AURA)
Jupiter's Great Red Spot Viewed by Voyager I
At about 89,000 miles in diameter, Jupiter could swallow 1,000 Earths. It is the largest planet in the solar system and perhaps the most majestic. Vibrant bands of clouds carried by winds that can exceed 400 mph continuously circle the planet's atmosphere. Such winds sustain spinning anticyclones like the Great Red Spot -- a raging storm three and a half times the size of Earth located in Jupiter’s southern hemisphere. In January and February 1979, NASA's Voyager 1 spacecraft zoomed toward Jupiter, capturing hundreds of images during its approach, including this close-up of swirling clouds around Jupiter's Great Red Spot. This image was assembled from three black and white negatives. The observations revealed many unique features of the planet that are still being explored to this day.
Credit: NASA's Goddard Space Flight Center. Video and images courtesy of NASA/JPL
Sounding Rocket Launches Into Aurora Over Venetie, Alaska
On March 3, 2014, at 6:09 a.m. EST, a NASA-funded sounding rocket launched straight into an aurora over Venetie, Alaska. The Ground-to-Rocket Electrodynamics – Electron Correlative Experiment (GREECE) sounding rocket mission, which launched from Poker Flat Research Range in Poker Flat, Alaska, will study classic curls in the aurora in the night sky.
The GREECE mission seeks to understand what combination of events sets up these auroral curls as they're called, in the charged, heated gas – or plasma – where aurorae form. This is a piece of information, which in turn, helps paint a picture of the sun-Earth connection and how energy and particles from the sun interact with Earth's own magnetic system, the magnetosphere.
Image Credit: NASA/Christopher Perry
No comments:
Post a Comment