Friday, March 1, 2013
The intentional swap at about 2:30 a.m. PST today (Thursday, Feb. 28) put the rover, as anticipated, into a minimal-activity precautionary status called "safe mode." The team is shifting the rover from safe mode to operational status over the next few days and is troubleshooting the condition that affected operations yesterday. The condition is related to a glitch in flash memory linked to the other, now-inactive, computer.
"We switched computers to get to a standard state from which to begin restoring routine operations," said Richard Cook of NASA's Jet Propulsion Laboratory, project manager for the Mars Science Laboratory Project, which built and operates Curiosity.
Like many spacecraft, Curiosity carries a pair of redundant main computers in order to have a backup available if one fails. Each of the computers, A-side and B-side, also has other redundant subsystems linked to just that computer. Curiosity is now operating on its B-side, as it did during part of the flight from Earth to Mars. It operated on its A-side from before the August 2012 landing through Wednesday.
"While we are resuming operations on the B-side, we are also working to determine the best way to restore the A-side as a viable backup," said JPL engineer Magdy Bareh, leader of the mission's anomaly resolution team.
The spacecraft remained in communications at all scheduled communication windows on Wednesday, but it did not send recorded data, only current status information. The status information revealed that the computer had not switched to the usual daily "sleep" mode when planned. Diagnostic work in a testing simulation at JPL indicates the situation involved corrupted memory at an A-side memory location used for addressing memory files.
Scientific investigations by the rover were suspended Wednesday and today. Resumption of science investigations is anticipated within several days. This week, laboratory instruments inside the rover have been analyzing portions of the first sample of rock powder ever collected from the interior of a rock on Mars.
NASA's Mars Science Laboratory Project is using Curiosity to assess whether areas inside Gale Crater ever offered a habitable environment for microbes. JPL, a division of the California Institute of Technology in Pasadena, manages the project for NASA's Science Mission Directorate in Washington.
More information about Curiosity is online at http://www.jpl.nasa.gov/msl , http://www.nasa.gov/msl and http://mars.jpl.nasa.gov/msl/ . You can follow the mission on Facebook at: http://www.facebook.com/marscuriosity and on Twitter at: http://www.twitter.com/marscuriosity . -
See more at: http://www.jpl.nasa.gov/news/news.php?release=2013-078#sthash.F7HBtNyS.dpuf
Wednesday, October 24, 2012
Friday, August 10, 2012
The panelists are:
-- Michael McDonald, Hubble Fellow, Massachusetts Institute of Technology, Cambridge, Mass.
-- Bradford Benson, astrophysicist, University of Chicago
-- Megan Donahue, professor of astronomy, Michigan State University, East Lansing
-- Martin Rees, professor of cosmology and astrophysics, University of Cambridge, United Kingdom
For dial-in information to ask questions, reporters must send their name, media affiliation and telephone number to email@example.com by noon Aug. 15.
The general public also can ask the panelists questions via Twitter using the hashtag #asknasa.
Audio of the teleconference will be streamed live at:
For more information about NASA's Chandra X-ray Observatory, visit:
Monday, October 24, 2011
Using data from the Herschel Space Observatory, astronomers have detected for the first time cold water vapor enveloping a dusty disk around a young star. The findings suggest that this disk, which is poised to develop into a solar system, contains great quantities of water, suggesting that water-covered planets like Earth may be common in the universe. Herschel is a European Space Agency mission with important NASA contributions.
Scientists previously found warm water vapor in planet-forming disks close to a central star. Evidence for vast quantities of water extending out into the cooler, far reaches of disks where comets take shape had not been seen until now. The more water available in disks for icy comets to form, the greater the chances that large amounts eventually will reach new planets through impacts.
"Our observations of this cold vapor indicate enough water exists in the disk to fill thousands of Earth oceans," said astronomer Michiel Hogerheijde of Leiden Observatory in The Netherlands. Hogerheijde is the lead author of a paper describing these findings in the Oct. 21 issue of the journal Science.
The star with this waterlogged disk, called TW Hydrae, is 10 million years old and located about 175 light-years away from Earth, in the constellation Hydra. The frigid, watery haze detected by Hogerheijde and his team is thought to originate from ice-coated grains of dust near the disk's surface. Ultraviolet light from the star causes some water molecules to break free of this ice, creating a thin layer of gas with a light signature detected by Herschel's Heterodyne Instrument for the Far-Infrared, or HIFI.
"These are the most sensitive HIFI observations to date," said Paul Goldsmith, NASA project scientist for the Herschel Space Observatory at the agency's Jet Propulsion Laboratory in Pasadena, Calif. "It is a testament to the instrument builders that such weak signals can be detected."
TW Hydrae is an orange dwarf star, somewhat smaller and cooler than our yellow-white sun. The giant disk of material that encircles the star has a size nearly 200 times the distance between Earth and the sun. Over the next few million years, astronomers believe matter within the disk will collide and grow into planets, asteroids and other cosmic bodies. Dust and ice particles will assemble as comets.
As the new solar system evolves, icy comets are likely to deposit much of the water they contain on freshly created worlds through impacts, giving rise to oceans. Astronomers believe TW Hydrae and its icy disk may be representative of many other young star systems, providing new insights on how planets with abundant water could form throughout the universe.
Herschel is a European Space Agency cornerstone mission launched in 2009, carrying science instruments provided by consortia of European institutes. NASA's Herschel Project Office based at JPL contributed mission-enabling technology for two of Herschel's three science instruments. The NASA Herschel Science Center, part of the Infrared Processing and Analysis Center at the California Institute of Technology in Pasadena, supports the U.S. astronomical community. Caltech manages JPL for NASA.
For NASA's Herschel website, visit: http://www.nasa.gov/herschel .
For ESA's Herschel website, visit: http://www.esa.int/SPECIALS/Herschel/index.html.
Friday, July 29, 2011
The Dawn science team is working to determine the significance of the distinct features in this image, which include large grooves or ridges extending for great distances around Vesta.
This image was taken by Dawn's framing camera on July 23, from a distance of 3,200 miles (5,200 kilometers).
The Dawn mission to Vesta and Ceres is managed by NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, for NASA. The University of California, Los Angeles, is responsible for overall Dawn mission science. The Dawn framing cameras have been developed and built under the leadership of the Max Planck Institute for Solar System Research, Katlenburg-Lindau, Germany, with significant contributions by DLR German Aerospace Center, Institute of Planetary Research, Berlin, and in coordination with the Institute of Computer and Communication Network Engineering, Braunschweig. The Framing Camera project is funded by the Max Planck Society, DLR, and NASA/JPL.
Friday, May 6, 2011
NASA Administrator Visits Jupiter-Bound Spacecraft
Juno will be carried into space aboard a United Launch Alliance Atlas V rocket, lifting off from Launch Complex-41 at the Cape Canaveral Air Force Station in Florida. The launch period opens Aug. 5, 2011, and extends through Aug. 26. For an Aug. 5 liftoff, the launch window opens at 8:39 a.m. PDT (11:39 am EDT) and remains open through 9:39 a.m. PDT (12:39 p.m. EDT).
NASA's Jet Propulsion Laboratory, Pasadena, Calif., manages the Juno mission for the principal investigator, Scott Bolton, of Southwest Research Institute at San Antonio. The Juno mission is part of the New Frontiers Program managed at NASA's Marshall Space Flight Center in Huntsville, Ala. Lockheed Martin Space Systems, Denver, built the spacecraft. Launch management for the mission is the responsibility of NASA's Launch Services Program at the Kennedy Space Center in Florida. JPL is a division of the California Institute of Technology in Pasadena.
Additional information about Juno is available at http://www.nasa.gov/juno .
Monday, April 11, 2011
An asteroid recently discovered by NASA's Wide-field Infrared Survey Explorer (WISE) may be a bit of an oddball. Most near-Earth asteroids -- NEAs for short -- have eccentric, or egg-shaped, orbits that take the asteroids right through the inner solar system. The new object, designated 2010 SO16, is different. Its orbit is almost circular such that it cannot come close to any other planet in the solar system except Earth.
However, even though the asteroid rides around with Earth, it never gets that close.
"It keeps well away from Earth," said Apostolos "Tolis" Christou, who, together with David Asher of the Armagh Observatory in Northern Ireland, analyzed the orbit of the body after it was discovered in infrared images taken by WISE. "So well, in fact, that it has likely been in this orbit for several hundred thousand years, never coming closer to our planet than 50 times the distance to the moon."
The asteroid is one of a few that trace out a horseshoe shape relative to Earth. As the asteroid approaches Earth, the planet's gravity causes the object to shift back into a larger orbit that takes longer to go around the sun than Earth. Alternately, as Earth catches up with the asteroid, the planet's gravity causes it to fall into a closer orbit that takes less time to go around the sun than Earth. The asteroid therefore never completely passes our planet. This slingshot-like effect results in a horseshoe-shaped path as seen from Earth, in which 2010 SO16 takes 175 years to get from one end of the horseshoe to the other.
"The origins of this object could prove to be very interesting," said Amy Mainzer of NASA's Jet Propulsion Laboratory, Pasadena, Calif., the principal investigator of NEOWISE, which is the asteroid- and comet-hunting portion of the WISE survey mission. "We are really excited that the astronomy community is already finding treasures in the NEOWISE data that have been released so far."
NEOWISE finished its one complete sweep of the solar system in early February of this year. Data on the orbits of asteroids and comets detected by the project, including near-Earth objects, are catalogued at the NASA-funded International Astronomical Union's Minor Planet Center, at the Smithsonian Astrophysical Observatory in Cambridge, Mass.
A full story from the Armagh Observatory, including animations, is online at http://www.arm.ac.uk/press/2011/aac_horseshoe_orbit.html.
JPL manages and operates the Wide-field Infrared Survey Explorer for NASA's Science Mission Directorate, Washington. The principal investigator, Edward Wright, is at UCLA. The mission was competitively selected under NASA's Explorers Program managed by the Goddard Space Flight Center, Greenbelt, Md. The science instrument was built by the Space Dynamics Laboratory, Logan, Utah, and the spacecraft was built by Ball Aerospace & Technologies Corp., Boulder, Colo. Science operations and data processing take place at the Infrared Processing and Analysis Center at the California Institute of Technology in Pasadena. Caltech manages JPL for NASA. More information is online at http://www.nasa.gov/, http://wise.astro.ucla.edu and http://jpl.nasa.gov/wise .
Tuesday, April 5, 2011
The amazing variety of colors seen in this image represents different wavelengths of infrared light. The bright white nebula in the center of the image is glowing due to heating from nearby stars, resulting in what is called an emission nebula. The same is true for most of the multi-hued gas prevalent throughout the entire image, including the bluish, bow-shaped feature near the bottom right. The bright red area in the bottom right is light from the star in the center – Sigma Scorpii – that is reflected off of the dust surrounding it, creating what is called a reflection nebula. And the much darker areas scattered throughout the image are pockets of cool, dense gas that block out the background light, resulting in absorption (or 'dark') nebulae. WISE's longer wavelength detectors can typically see through dark nebulae, but these are exceptionally opaque.
JPL manages and operates the Wide-field Infrared Survey Explorer for NASA's Science Mission Directorate, Washington. The principal investigator, Edward Wright, is at UCLA. The mission was competitively selected under NASA's Explorers Program managed by the Goddard Space Flight Center, Greenbelt, Md. The science instrument was built by the Space Dynamics Laboratory, Logan, Utah, and the spacecraft was built by Ball Aerospace & Technologies Corp., Boulder, Colo. Science operations and data processing take place at the Infrared Processing and Analysis Center at the California Institute of Technology in Pasadena. Caltech manages JPL for NASA. More information is online at http://www.nasa.gov/wise and http://wise.astro.ucla.edu and http://jpl.nasa.gov/wise .
Thursday, March 31, 2011
Sagan once said, "Somewhere, something incredible is waiting to be known," which is in line with the Sagan Fellowship's primary goal: to discover and characterize planetary systems and Earth-like planets around other stars. Planets outside of our solar system are called exoplanets. The fellowship also aims to support outstanding recent postdoctoral scientists in conducting independent research broadly related to the science goals of NASA's Exoplanet Exploration Program.
Previous Sagan Fellows have contributed significant discoveries in exoplanet exploration. including: the first characterizations of a super-Earth's atmosphere using a ground-based telescope; and the discovery of a massive disk of dust and gas encircling a giant young star, which could potentially answer the long-standing question of how massive stars are born.
"The Sagan Fellowship program seeks to identify the most highly qualified young researchers in the field of exoplanets. Nowhere is the dynamism of this young branch of astronomy demonstrated more dramatically than by the intellectual quality and enthusiasm of these five new Sagan Fellows," said Charles Beichman, executive director of the NASA Exoplanet Science Institute at the California Institute of Technology in Pasadena. "These scientists are certain to be leaders of this exciting and rapidly growing field for many years to come."
The program, created in 2008, awards selected postdoctoral scientists with annual stipends of approximately $64,500 for up to three years, plus an annual research budget of up to $16,000. Topics range from techniques for detecting the glow of a dim planet in the blinding glare of its host star, to searching for the crucial ingredients of life in other planetary systems.
The 2011 Sagan Fellows are:
-- David Kipping, who will work at the Harvard-Smithsonian Center for Astrophysics, Cambridge, to combine theory and observation to conduct a search for the moons of exoplanets.
-- Bryce Croll, who will work at the Massachusetts Institute of Technology, Cambridge, Mass., to characterize the atmospheres of both large and small exoplanets using a variety of telescopes.
-- Wladimir Lyra, who will work at NASA's Jet Propulsion Laboratory, Pasadena, Calif., to study planet-forming disks and exoplanet formation.
-- Katie Morzinski, who will work at the University of Arizona, Tucson, to commission and employ high-contrast adaptive optics systems that will directly image Jupiter-like exoplanets.
-- Sloane Wiktorowicz, who will work at the University of California, Santa Cruz to use a technique called optical polarimetry to directly detect exoplanets.
NASA has two other astrophysics theme-based fellowship programs: the Einstein Fellowship Program, which supports research into the physics of the cosmos, and the Hubble Fellowship Program, which supports research into cosmic origins. The Sagan Fellowship Program is administered by the NASA Exoplanet Science Institute as part of NASA's Exoplanet Exploration Program at JPL in Pasadena, Calif. The California Institute of Technology manages JPL for NASA.
A full description of the 2011 fellows and their projects, and other information about these programs is available at: http://nexsci.caltech.edu/sagan/2011postdocRecipients.shtml .
More information about NASA's Astrophysics Division is at: http://nasascience.nasa.gov/astrophysics .
Wednesday, March 30, 2011
Vesta is most commonly called an asteroid because it lies in the orbiting rubble patch known as the main asteroid belt between Mars and Jupiter. But the vast majority of objects in the main belt are lightweights, 100-kilometers-wide (about 60-miles wide) or smaller, compared with Vesta, which is about 530 kilometers (330 miles) across on average. In fact, numerous bits of Vesta ejected by collisions with other objects have been identified in the main belt.
"I don't think Vesta should be called an asteroid," said Tom McCord, a Dawn co-investigator based at the Bear Fight Institute, Winthrop, Wash. "Not only is Vesta so much larger, but it's an evolved object, unlike most things we call asteroids."
The layered structure of Vesta (core, mantle and crust) is the key trait that makes Vesta more like planets such as Earth, Venus and Mars than the other asteroids, McCord said. Like the planets, Vesta had sufficient radioactive material inside when it coalesced, releasing heat that melted rock and enabled lighter layers to float to the outside. Scientists call this process differentiation.
McCord and colleagues were the first to discover that Vesta was likely differentiated when special detectors on their telescopes in 1972 picked up the signature of basalt. That meant that the body had to have melted at one time.
Officially, Vesta is a "minor planet" -- a body that orbits the sun but is not a proper planet or comet. But there are more than 540,000 minor planets in our solar system, so the label doesn't give Vesta much distinction. Dwarf planets – which include Dawn's second destination, Ceres -- are another category, but Vesta doesn't qualify as one of those. For one thing, Vesta isn't quite large enough.
Dawn scientists prefer to think of Vesta as a protoplanet because it is a dense, layered body that orbits the sun and began in the same fashion as Mercury, Venus, Earth and Mars, but somehow never fully developed. In the swinging early history of the solar system, objects became planets by merging with other Vesta-sized objects. But Vesta never found a partner during the big dance, and the critical time passed. It may have had to do with the nearby presence of Jupiter, the neighborhood's gravitational superpower, disturbing the orbits of objects and hogging the dance partners.
Other space rocks have collided with Vesta and knocked off bits of it. Those became debris in the asteroid belt known as Vestoids, and even hundreds of meteorites that have ended up on Earth. But Vesta never collided with something of sufficient size to disrupt it, and it remained intact. As a result, Vesta is a time capsule from that earlier era.
"This gritty little protoplanet has survived bombardment in the asteroid belt for over 4.5 billion years, making its surface possibly the oldest planetary surface in the solar system," said Christopher Russell, Dawn's principal investigator, based at UCLA. "Studying Vesta will enable us to write a much better history of the solar system's turbulent youth."
Dawn's scientists and engineers have designed a master plan to investigate these special features of Vesta. When Dawn arrives at Vesta in July, the south pole will be in full sunlight, giving scientists a clear view of a huge crater at the south pole. That crater may reveal the layer cake of materials inside Vesta that will tell us how the body evolved after formation. The orbit design allows Dawn to map new terrain as the seasons progress over its 12-month visit. The spacecraft will make many measurements, including high-resolution data on surface composition, topography and texture. The spacecraft will also measure the tug of Vesta's gravity to learn more about its internal structure.
"Dawn's ion thrusters are gently carrying us toward Vesta, and the spacecraft is getting ready for its big year of exploration," said Marc Rayman, Dawn's chief engineer at NASA's Jet Propulsion Laboratory, Pasadena, Calif. "We have designed our mission to get the most out of this opportunity to reveal the exciting secrets of this uncharted, exotic world."
The Dawn mission to Vesta and Ceres is managed by the Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, for NASA's Science Mission Directorate, Washington. The Dawn mission is part of the Discovery Program managed by NASA's Marshall Space Flight Center in Huntsville, Ala. UCLA is responsible for overall Dawn mission science. Orbital Sciences Corporation of Dulles, Va., designed and built the Dawn spacecraft. The German Aerospace Center, the Max Planck Society, the Italian Space Agency and the Italian National Astrophysical Institute are part of the mission team.
For more information about Dawn, visit http://www.nasa.gov/dawn and http://dawn.jpl.nasa.gov .
Tuesday, March 29, 2011
Students from three California schools – South High School, Torrance; West Covina High School, West Covina; and Diamond Bar High School, Diamond Bar, won the overall regional competition. Two other California schools also took top honors. Chaminade College Preparatory, West Hills, receied the coveted Regional Chairman's award, while Foshay Learning Center, Los Angeles, a team mentored by NASA's Jet Propulsion Laboratory in Pasadena, Calif., took home the Engineering Inspiration award.
The winners will represent the California region at the FIRST championships April 27 to 30 in St. Louis, where they will compete against 51,000 other students on more than 2,000 teams.
The FIRST program was founded two decades ago to encourage students to pursue careers in science and technology through robotics competitions. With the help of engineers from JPL, aerospace and other companies and institutions of higher education, FIRST continues to grow and inspire students.
For more information, visit: http://www.usfirst.org/ .
Tuesday, March 8, 2011
The nearly 20-year study reveals that in 2006, a year in which comparable results for mass loss in mountain glaciers and ice caps are available from a separate study conducted using other methods, the Greenland and Antarctic ice sheets lost a combined mass of 475 gigatonnes a year on average. That's enough to raise global sea level by an average of 1.3 millimeters (.05 inches) a year. (A gigatonne is one billion metric tons, or more than 2.2 trillion pounds.)
The pace at which the polar ice sheets are losing mass was found to be accelerating rapidly. Each year over the course of the study, the two ice sheets lost a combined average of 36.3 gigatonnes more than they did the year before. In comparison, the 2006 study of mountain glaciers and ice caps estimated their loss at 402 gigatonnes a year on average, with a year-over-year acceleration rate three times smaller than that of the ice sheets.
"That ice sheets will dominate future sea level rise is not surprising -- they hold a lot more ice mass than mountain glaciers," said lead author Eric Rignot, jointly of NASA's Jet Propulsion Laboratory, Pasadena, Calif., and the University of California, Irvine. "What is surprising is this increased contribution by the ice sheets is already happening. If present trends continue, sea level is likely to be significantly higher than levels projected by the United Nations Intergovernmental Panel on Climate Change in 2007. Our study helps reduce uncertainties in near-term projections of sea level rise."
Rignot's team combined nearly two decades (1992-2009) of monthly satellite measurements with advanced regional atmospheric climate model data to examine changes in ice sheet mass and trends in acceleration of ice loss.
The study compared two independent measurement techniques. The first characterized the difference between two sets of data: interferometric synthetic aperture radar data from European, Canadian and Japanese satellites and radio echo soundings, which were used to measure ice exiting the ice sheets; and regional atmospheric climate model data from Utrecht University, The Netherlands, used to quantify ice being added to the ice sheets. The other technique used eight years of data from the NASA/German Aerospace Center's Gravity Recovery and Climate Experiment (Grace) satellites, which track minute changes in Earth's gravity field due to changes in Earth's mass distribution, including ice movement.
The team reconciled the differences between techniques and found them to be in agreement, both for total amount and rate of mass loss, over their data sets' eight-year overlapping period. This validated the data sets, establishing a consistent record of ice mass changes since 1992.
The team found that for each year over the 18-year study, the Greenland ice sheet lost mass faster than it did the year before, by an average of 21.9 gigatonnes a year. In Antarctica, the year-over-year speedup in ice mass lost averaged 14.5 gigatonnes.
"These are two totally independent techniques, so it is a major achievement that the results agree so well," said co-author Isabella Velicogna, also jointly with JPL and UC Irvine. "It demonstrates the tremendous progress that's being made in estimating how much ice the ice sheets are gaining and losing, and in analyzing Grace's time-variable gravity data."
The authors conclude that, if current ice sheet melting rates continue for the next four decades, their cumulative loss could raise sea level by 15 centimeters (5.9 inches) by 2050. When this is added to the predicted sea level contribution of 8 centimeters (3.1 inches) from glacial ice caps and 9 centimeters (3.5 inches) from ocean thermal expansion, total sea level rise could reach 32 centimeters (12.6 inches). While this provides one indication of the potential contribution ice sheets could make to sea level in the coming century, the authors caution that considerable uncertainties remain in estimating future ice loss acceleration.
Study results are published this month in Geophysical Research Letters. Other participating institutions include the Institute for Marine and Atmospheric Research, Utrecht University, The Netherlands; and the National Center for Atmospheric Research, Boulder, Colo.
JPL developed Grace and manages the mission for NASA. The University of Texas Center for Space Research in Austin has overall mission responsibility. GeoForschungsZentrum Potsdam (GFZ), Potsdam, Germany, is responsible for German mission elements.
More on Grace is online at http://www.csr.utexas.edu/grace/ and http://grace.jpl.nasa.gov/ .
Wednesday, February 16, 2011
The findings are a key step in understanding how dark matter, an invisible substance permeating our universe, contributed to the birth of massive galaxies in the early universe.
"If you start with too little dark matter, then a developing galaxy would peter out," said astronomer Asantha Cooray of the University of California, Irvine. He is the principal investigator of new research appearing in the journal Nature, online on Feb. 16 and in the Feb. 24 print edition. "If you have too much, then gas doesn't cool efficiently to form one large galaxy, and you end up with lots of smaller galaxies. But if you have the just the right amount of dark matter, then a galaxy bursting with stars will pop out."
The right amount of dark matter turns out to be a mass equivalent to 300 billion of our suns.
Herschel launched into space in May 2009. The mission's large, 3.5-meter (11.5-foot) telescope detects longer-wavelength infrared light from a host of objects, ranging from asteroids and planets in our own solar system to faraway galaxies.
"This remarkable discovery shows that early galaxies go through periods of star formation much more vigorous than in our present-day Milky Way," said William Danchi, Herschel program scientist at NASA Headquarters in Washington. "It showcases the importance of infrared astronomy, enabling us to peer behind veils of interstellar dust to see stars in their infancy."
Cooray and colleagues used the telescope to measure infrared light from massive, star-forming galaxies located 10 to 11 billion light-years away. Astronomers think these and other galaxies formed inside clumps of dark matter, similar to chicks incubating in eggs.
Giant clumps of dark matter act like gravitational wells that collect the gas and dust needed for making galaxies. When a mixture of gas and dust falls into a well, it condenses and cools, allowing new stars to form. Eventually enough stars form, and a galaxy is born.
Herschel was able to uncover more about how this galaxy-making process works by mapping the infrared light from collections of very distant, massive star-forming galaxies. This pattern of light, called the cosmic infrared background, is like a web that spreads across the sky. Because Herschel can survey large areas quickly with high resolution, it was able to create the first detailed maps of the cosmic infrared background.
"It turns out that it's much more effective to look at these patterns rather than the individual galaxies," said Jamie Bock of NASA's Jet Propulsion Laboratory in Pasadena, Calif. Bock is the U.S. principal investigator for Herschel's Spectral and Photometric Imaging Receiver instrument used to make the maps. "This is like looking at a picture in a magazine from a reading distance. You don't notice the individual dots, but you see the big picture. Herschel gives us the big picture of these distant galaxies, showing the influence of dark matter."
The maps showed the galaxies are more clustered into groups than previously believed. The amount of galaxy clustering depends on the amount of dark matter. After a series of complicated numerical simulations, the astronomers were able to determine exactly how much dark matter is needed to form a single star-forming galaxy.
"This measurement is important, because we are homing in on the very basic ingredients in galaxy formation," said Alexandre Amblard of UC Irvine, first author of the Nature paper. "In this case, the ingredient, dark matter, happens to be an exotic substance that we still have much to learn about."
NASA's Herschel Project Office is based at JPL, which contributed mission-enabling technology for two of Herschel's three science instruments. The NASA Herschel Science Center, part of the Infrared Processing and Analysis Center at the California Institute of Technology in Pasadena, supports the U.S. astronomical community. JPL is managed by Caltech.
More information is online at http://www.herschel.caltech.edu, http://www.nasa.gov/herschel and http://www.esa.int/SPECIALS/Herschel/index.html .
Wednesday, February 9, 2011
After a final match between Santa Monica High and Arcadia High, with a score of 64-56, the Santa Monica team secured their spot as the champions of the 12th annual Los Angeles "Surf Bowl."
The annual event, based on ocean sciences, focused on four main disciplines: biology, chemistry, geology, and the physical properties of the marine/coastal environment.
Santa Monica High School earned an all-expense paid trip to compete in the National Ocean Sciences Bowl at Texas A&M University at Galveston, April 29 through May 1. About 2,000 students from more than 300 high schools nationwide will participate in this academic competition. The theme for this year's competition is "Human Responses to Ocean Events."
The competition was developed to foster the next generation of marine scientists, researchers and environmental advocates. The National Ocean Sciences Bowl is a program of the nonprofit Consortium for Oceanographic Research and Education, based in Washington, D.C. USC's Wrigley Institute for Environmental Studies and NASA's Jet Propulsion Laboratory, Pasadena, Calif., co-host the academic competition. JPL is managed by the California Institute of Technology in Pasadena.
Thursday, January 27, 2011
The University of New Mexico leads the project, and NASA's Jet Propulsion Laboratory, Pasadena, Calif., provides the advanced digital electronic systems, which represent a major component of the observatory.
The first station in the Long Wavelength Array, with 256 antennas, is scheduled to start surveying the sky by this summer. When complete, the Long Wavelength Array will consist of 53 stations, with a total of 13,000 antennas strategically placed in an area nearly 400 kilometers (248 miles) in diameter. The antennas will provide sensitive, high-resolution images of a region of the sky hundreds of times larger than the full moon. These images could reveal radio waves coming from planets outside our solar system, and thus would turn out to be a new way to detect these worlds. In addition to planets, the telescope will pick up a host of other cosmic phenomena.
"We'll be looking for the occasional celestial flash," said Joseph Lazio, a radio astronomer at JPL. "These flashes can be anything from explosions on surfaces of nearby stars, deaths of distant stars, exploding black holes, or even perhaps transmissions by other civilizations." JPL scientists are working with multi-institutional teams to explore this new area of astronomy. Lazio is lead author of an article reporting scientific results from the Long Wavelength Demonstrator Array, a precursor to the new array, in the December 2010 issue of Astronomical Journal.
The new Long Wavelength Array will operate in the radio-frequency range of 20 to 80 megahertz, corresponding to wavelengths of 15 meters to 3.8 meters (49.2 feet to 12.5 feet). These frequencies represent one of the last and most poorly explored regions of the electromagnetic spectrum.
In recent years, a few factors have triggered revived interest in radio astronomy at these frequencies. The cost and technology required to build these low-frequency antennas has improved significantly. Also, advances in computing have made the demands of image processing more attainable. The combination of cost-effective hardware and technology gives scientists the ability to return to these wavelengths and obtain a much better view of the universe.
The predecessor Long Wavelength Demonstrator Array was also in New Mexico. It was successful in identifying radio flashes, but all of them came from non-astronomy targets -- either the sun, or meteors reflecting TV signals high in Earth's atmosphere. Nonetheless, its findings indicate how future searches using the Long Wavelength Array technology might lead to new discoveries.
Radio astronomy was born at frequencies below 100 megahertz and developed from there. The discoveries and innovations at this frequency range helped pave the way for modern astronomy. Perhaps one of the most important contributions made in radio astronomy was by a young graduate student at New Hall (since renamed Murray Edwards College) of the University of Cambridge, U.K. Jocelyn Bell discovered the first hints of radio pulsars in 1967, a finding that was later awarded a Nobel Prize. Pulsars are neutron stars that beam radio waves in a manner similar to a lighthouse beacon.
Long before Bell's discovery, astronomers believed that neutron stars, remnants of certain types of supernova explosions, might exist. At the time, however, the prediction was that these cosmic objects would be far too faint to be detected. When Bell went looking for something else, she stumbled upon neutron stars that were in fact pulsing with radio waves -- the pulsars. Today about 2,000 pulsars are known, but within the past decade, a number of discoveries have hinted that the radio sky might be far more dynamic than suggested by just pulsars.
"Because nature is more clever than we are, it's quite possible that we will discover something we haven't thought of," said Lazio.
More information on the Long Wavelength Array is online at: http://lwa.unm.edu .
The Long Wavelength Array project is led by the University of New Mexico, Albuquerque, N.M., and includes the Los Alamos National Laboratory, N.M., the United States Naval Research Laboratories, Washington, and NASA's Jet Propulsion Laboratory, Pasadena, Calif. The California Institute of Technology manages JPL for NASA.
Thursday, January 20, 2011
Soon after its release in January 2010, Space Images was selected as a "Staff Favorite" in iTunes and quickly became a top app in the Education category. It has since received praise from users for its extensive and stunning collection of images taken by NASA/JPL spacecraft and for its educational uses.
The new version, Space Images 2.0, optimized for iPad and iPhone 4, brings even more stellar photos to viewers' fingertips, plus videos, Facebook and Twitter connectivity, and a new format that makes it easier to browse through photos at a higher resolution. It will be available in the iTunes Store this spring.
Droid more your style? Space Images 2.0 for Android devices is coming soon.
Visit http://bit.ly/e2yy4y to download Space Images free in the iTunes App Store. Explore more mobile offerings from JPL at http://www.jpl.nasa.gov/onthego/index.cfm?cid=500kweb.
Wednesday, January 5, 2011
Opportunity arrived at the western edge of Santa Maria crater in mid-December and will spend about two months investigating rocks there. That investigation will take Opportunity into the beginning of its eighth year on Mars. Opportunity landed in the Meridiani Planum region of Mars on Jan. 25, 2004, Universal Time (Jan. 24, Pacific Time) for a mission originally planned to last for three months.
The new image is online at http://www.nasa.gov/mission_pages/mer/multimedia/gallery/pia13754-anno.html and http://hirise.lpl.arizona.edu/releases/oppy-santa-maria.php .
Opportunity and its twin, Spirit, which passed its seventh anniversary on Mars this week, both have made important discoveries about wet environments on ancient Mars that may have been favorable for supporting microbial life.
NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Mars Reconnaissance Orbiter and Mars Exploration Rover projects for NASA's Science Mission Directorate, Washington. Lockheed Martin Space Systems, Denver, built the orbiter. The University of Arizona, Tucson, operates the HiRISE camera, which was built by Ball Aerospace & Technologies Corp., Boulder, Colo.
Wednesday, December 29, 2010
The Deep Space Network (DSN) consists of three communications complexes: in Goldstone, Calif.; Madrid, Spain; and Canberra, Australia. The 70-meter antennas are more than 40 years old and are showing signs of surface deterioration from constant use. Additional 34-meter antennas are being installed in Canberra in the first phase; subsequent phases will install additional 34-meter antennas in Goldstone and Madrid.
The 34-meter beam waveguide antennas are essential to keep communications flowing smoothly as NASA's fleet of spacecraft continues to expand. In addition, the waveguide design of the antennas provides easier access for maintenance and future upgrades, because sensitive electronics are housed in a below-the-ground pedestal equipment room, instead of in the center of the dish.
"As a result of several studies, it was determined that arrays of 34-meter beam waveguide antennas were the best solution to long-term continuation of DSN 70-meter capabilities," said Miguel Marina, who manages the 70-meter replacement task force at NASA's Jet Propulsion Laboratory in Pasadena, Calif. "The new antennas are critical communication resources for all current and future NASA missions."
NASA expects to complete the building of the first two 34-meter antennas in Canberra by 2016. They will be named Deep Space Stations 35 and 36. Deep Space Station 35 is due to be online in 2014, and Deep Space Station 36 is expected to follow in 2016.
In 1958, NASA established the Deep Space Network as a separately managed and operated communications facility to accommodate all deep space missions. This avoided the need for each flight project to acquire its own specialized space communications network. During the Apollo period (1967-1972), these stations supported America's missions to the moon, including the historic first manned landing. The Goldstone antenna, in particular, captured Neil Armstrong's words and sent them on to American television sets while the images came through another antenna.
The Deep Space Network is now sending commands to numerous robotic spacecraft, such as NASA's Mars Exploration Rovers, the Spitzer Space Telescope, the Saturn explorer Cassini and the two Voyager spacecraft, which are near the edge of the solar system.
JPL, a division of the California Institute of Technology in Pasadena, manages the Deep Space Network for NASA Headquarters, Washington. More information about the Deep Space Network is online at: http://deepspace.jpl.nasa.gov . More information about NASA's Space Communications and Navigation program is at: https://www.spacecomm.nasa.gov .
Wednesday, December 22, 2010
From space, NASA satellites record the change of seasons. Satellite images show large parts of the landscape at one time. They help scientists study regional patterns on Earth. These images also help show bigger changes that may occur over many years.
A new slide show, "The Change of Seasons: Views from Space," shows some of the ways seasonal change affects our planet, and invites you to share your own photos of seasonal change where you live: http://www.jpl.nasa.gov/education/seasons.cfm .
Monday, December 13, 2010
The event drew more than 260 students and teachers representing 16 schools from throughout Southern California. This year's challenge was to build a unique device capable of lifting an officially supplied ping-pong ball and cause the ball to touch and hold against a ceiling located 2 meters (about 6.6 feet) above ground. The winner completed this task in the fastest time.
A total of 19 student teams competed side-by-side with 15 teams that included JPL engineers. There was a tie for the winning JPL team between P.C. Chen and David Van Buren, while second place went to Richard Goldstein and third place to Bob Krylo.
The requirements this year: The devices had to be initiated by a single operation (cut a string, flick a switch, etc.), use safe energy sources, and could be no larger, prior to the start of the task than 50 centimeters (19.7 inches) high by 1.2 meters (about 3.9 feet) wide by 1.2 meters (about 3.9 feet) long. The devices had to be made from non-toxic and safe materials.
The rules change each year, but the results remain consistent: Students challenge themselves, solve problems and appreciate that math, science and engineering can be fun.
When asked for the key to their success, Yunis Karaca, the team's mentor replied, "We first brainstormed and then I let the kids use their imagination."
Monday, December 6, 2010
The team determined the planet, GJ 1214b, is either blanketed with a thin layer of water steam or surrounded by a thick layer of high clouds. If the former, the planet itself would have an icy composition. If the latter, the planet would be rocky or similar to the composition of Neptune, though much smaller.
"This is the first super-Earth known to have an atmosphere," said Jacob Bean, a NASA Sagan Fellow and astronomer at the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass. "But even with these new measurements, we can't say yet what that atmosphere is made of. This world is being very shy and veiling its true nature from us."
GJ 1214b, first discovered in December 2009, is 2.7 times the size of Earth and 6.5 times as massive. Previous observations of the planet's size and mass demonstrated it has a low density for its size, leading astronomers to conclude the planet is some kind of solid body with an atmosphere.
The planet orbits close to its dim star, at a distance of 0.014 astronomical units. An astronomical unit is the distance between Earth and the sun, approximately 93 million miles. GJ 1214b circles too close to its star to be habitable by any life forms.
Bean and his team observed infrared light as the planet crossed in front of its star. During such transits, the star's light filters through the atmosphere. Gases absorb the starlight at particular wavelengths, leaving behind chemical fingerprints detectable from Earth. This same type of technique has been used to study the atmospheres of distant "hot Jupiters," or Jupiter-like planets orbiting close to their stars, and found gases like hydrogen, methane and sodium vapor.
In the case of the super-Earth, no chemical fingerprints were detected; however, this doesn't mean there are no chemicals present. Instead, this information ruled out some possibilities for GJ 1214b's atmosphere, and narrowed the scope to either an atmosphere of water steam or high clouds. Astronomers believe it's more likely the atmosphere is too thin around the planet to let enough light filter through and reveal chemical fingerprints.
"A steamy atmosphere would have to be very dense – about one-fifth water vapor by volume -- compared to our Earth, with an atmosphere that's four-fifths nitrogen and one-fifth oxygen with only a touch of water vapor," Bean said. "During the next year, we should have some solid answers about what this planet is truly like."
The team, which included Bean's co-authors -- Eliza Miller-Ricci Kempton, a NASA Sagan Fellow at the University of California in Santa Cruz, and Derek Homeier of the Institute for Astrophysics in Gottingen, Germany -- examined GJ 1214b using the ground-based Very Large Telescope at Paranal Observatory in Chile.
"This is an important step forward, narrowing our understanding of the atmosphere of this planet," said NASA Exoplanet Exploration Program Scientist Douglas Hudgins at NASA Headquarters in Washington. "Bizarre worlds like this make exoplanet science one of the most compelling areas in astrophysics today."
The Sagan Fellowship Program is administered by the NASA Exoplanet Science Institute at the California Institute of Technology in Pasadena. Its purpose is to advance the scientific and technical goals of NASA's Exoplanet Exploration Program. The program is managed for NASA by the Jet Propulsion Laboratory in Pasadena, Calif. Caltech manages JPL for NASA.
More information about NASA's planet-finding missions is online at:http://planetquest.jpl.nasa.gov . More information about NASA's Sagan Fellowship Program is at http://nexsci.caltech.edu/sagan .
Wednesday, December 1, 2010
Major goals for NASA's Mars Science Laboratory include assessing the modern environment in its landing area, as well as clues to environments billions of years ago. The environment station from Spain will fill a central role in studying modern conditions by measuring daily and seasonal changes.
The Rover Environmental Monitoring Station, or REMS, is one of 10 instruments in the mission's science payload. REMS uses sensors on the mast, on the deck and inside the body of the mission's car-size rover, Curiosity. Spain's Ministry of Science and Innovation and Spain's Center for Industrial Technology Development supplied the instrument. Components were installed on Curiosity in September and are being tested at NASA's Jet Propulsion Laboratory, Pasadena, Calif.
While most of Curiosity's electronics are sheltered for some protection from the Martian environment, the team that developed and built the environmental station needed to fashion external sensors that could tolerate the temperature extremes that some of them would be monitoring.
"That was our biggest engineering challenge," said REMS Principal Investigator Javier Gómez-Elvira, an aeronautical engineer with the Centro de Astrobiología, Madrid, Spain. "The sensors will get very cold and go through great changes in temperature every day." The Center for Astrobiology is affiliated with the Spanish National Research Council and the National Institute for Aerospace Technology.
The air temperature around the rover mast will likely drop to about minus 130 degrees Celsius (about minus 202 degrees Fahrenheit) some winter nights and climb to about minus 50 C (about minus 60 F) by 12 hours later. On warmer days, afternoon air temperatures could reach a balmy 10 to 30 C (50 to 86 F), depending on which landing site is selected.
Other challenges have included accounting for how the rover itself perturbs air movement, and keeping the entire weather station's mass to just 1.3 kilograms (2.9 pounds).
The instrument will record wind speed, wind direction, air pressure, relative humidity, air temperature and ground temperature, plus one variable that has not been measured by any previous weather station on the surface of Mars: ultraviolet radiation. Operational plans call for taking measurements for five minutes every hour of the 23-month-long mission. Twenty-three months is equal to approximately one Martian year.
Monitoring ground temperature and ultraviolet radiation along with other weather data will contribute to understanding the Martian climate and will aid the mission's assessment of whether the current environment around the rover has conditions favorable for microbial life.
"It is important to know the temperature and humidity right at ground level," said Gómez-Elvira. Humidity at the landing sites will be extremely low, but knowing daily humidity cycles at ground level could help researchers understand the interaction of water vapor between the soil and the atmosphere. If the environment supports, or ever supported, any underground microbes, that interaction could be key.
Ultraviolet radiation can also affect habitability. For example, germ-killing ultraviolet lamps are commonly used to help maintain sterile conditions for medical and research equipment. The ultraviolet sensor Curiosity's deck measures six different wavelength bands in the ultraviolet portion of the spectrum, including wavelengths also monitored from above by NASA's Mars Reconnaissance Orbiter.
The weather station will help extend years of synergy between missions that study Mars from orbit and missions on the surface.
"We will gain information about whether local conditions are favorable for habitability, and we will also contribute to understanding the global atmosphere of Mars," said Gómez-Elvira. "The circulation models of the Mars atmosphere are based mainly on observations by orbiters. Our measurements will provide a way to verify and improve the models."
For example, significant fractions of the Martian atmosphere freeze onto the ground as a south polar carbon-dioxide ice cap during southern winter and as a north polar carbon-dioxide ice cap in northern winter, returning to the atmosphere in each hemisphere's spring. At Curiosity's landing site far from either pole, REMS will check whether seasonal patterns of changing air pressure fit the existing models for effects of the coming and going of polar carbon-dioxide ice.
The sensor for air pressure, developed for REMS by the Finnish Meteorological Institute, uses a dust-shielded opening on Curiosity's deck. The most conspicuous components of the weather station are two fingers extending horizontally from partway up the rover's remote-sensing mast. Each of these two REMS mini-booms holds three electronic sensors for detecting air movement in three dimensions. Placement of the booms at an angle of 120 degrees from each other enables calculating the velocity of wind without worrying about the main mast blocking the wind. One mini-boom also holds the humidity sensor; the other a set of directional infrared sensors for measuring ground temperature.
To develop REMS and prepare for analyzing the data it will provide, Spain has assembled a team of about 40 researchers -- engineers and scientists. The team plans to post daily Mars weather reports online.
Monday, November 29, 2010
These "sandbars," or filaments, are known to span vast distances between galaxy clusters and form a lattice-like structure known as the cosmic web. Though immense, these filaments are difficult to see and study in detail. Two years ago, Spitzer's infrared eyes revealed that one such intergalactic filament containing star-forming galaxies ran between the galaxy clusters called Abell 1763 and Abell 1770.
Now these observations have been bolstered by the discovery, inside this same filament, of a galaxy that has a rare boomerang shape and unusual light emissions. Hot gas is sweeping the wandering galaxy into this shape as it passes through the filament, presenting a new way to gauge the filament's particle density. Researchers hope that other such galaxies with oddly curved profiles could serve as signposts for the faint threads, which in turn signify regions ripe for forming stars.
"These filaments are integral to the evolution of galaxy clusters -- among the biggest gravitationally bound objects in the universe -- as well as the creation of new generations of stars," said Louise Edwards, a postdoctoral researcher at the California Institute of Technology in Pasadena, and lead author of a study detailing the findings in the Dec. 1 issue of the Astrophysical Journal Letters. Her collaborators are Dario Fadda, also at Caltech, and Dave Frayer from the National Science Foundation's National Radio Astronomy Observatory, based in Charlottesville, Virginia.
Blowing in the cosmic breeze
Astronomers spotted the bent galaxy about 11 million light-years away from the center of the galaxy cluster Abell 1763 during follow-up observations with the WIYN Observatory near Tucson, Ariz., and radio-wave observations by the Very Large Array near Socorro, N.M. The WIYN Observatory is named after the consortium that owns and operates it, which includes the University of Wisconsin, Indiana University, Yale University, and the National Optical Astronomy Observatories.
The galaxy has an unusual ratio of radio to infrared light, as measured by the Very Large Array and Spitzer, making it stand out like a beacon. This is due in part to the galaxy having twin jets of material spewing in opposite directions from a supermassive black hole at its center. These jets have puffed out into giant lobes of material that emit a tremendous amount of radio waves.
Edwards and her colleagues noticed that these lobes appear to be bent back and away from the galaxy's trajectory through the filament. This bow shape, the astronomers reasoned, is due to particles in the filament pushing on the gas and dust in the lobes.
By measuring the angle of the arced lobes, Edwards' team calculated the pressure exerted by the filaments' particles and then determined the density of the medium. The method is somewhat like looking at streamers on a kite soaring overhead to judge the wind strength and the thickness of the air.
According to the data, the density inside this filament is indeed about 100 times the average density of the universe. This value agrees with that obtained in a previous X-ray study of filaments and also nicely matches predictions of supercomputer simulations.
Galaxies tend to bunch together as great islands in the void of space, called galaxy clusters. These galaxy groupings themselves often keep company with other clusters in "superclusters" that loom as gargantuan, gravitationally associated walls of galaxies. These structures evolved from denser patches of material as the universe rapidly expanded after the Big Bang, some 13.7 billion years ago.
The clumps and threads of this primordial matter eventually cooled, and some of it has condensed into the galaxies we see today. The leftover gas is strewn in filaments between galaxy clusters. Much of it is still quite hot -- about one million degrees Celsius (1.8 million degrees Fahrenheit) -- and blazes in high-energy X-rays that permeate galaxy clusters. Filaments are therefore best detected in X-ray light, and one direct density reading of the strands has previously been obtained in this band of frequencies.
But the X-ray-emitting gas in filaments is much more diffuse and weak than in clusters, just as submerged sandbars are extremely hard to spot at sea compared to islands poking above the water. Therefore, obtaining quality observations of filaments is time-consuming with current space observatories.
The technique by Edwards and her colleagues, which uses radio frequencies that can reach a host of ground-based telescopes, points to an easier way to probe the interiors of galaxy-cluster filaments. Instead of laboring to find subtle X-rays clues, astronomers could trust these arced "lighthouse" galaxies to indicate just where cosmic filaments lie.
Knowing how much material these filaments contain and how they interact with galaxy clusters will be very important for understanding the overall evolution of the universe, Edwards said.
The Spitzer observations were made before it ran out of its liquid coolant in May 2009 and began its warm mission.
NASA's Jet Propulsion Laboratory, Pasadena, Calif., manages the Spitzer Space Telescope mission for NASA's Science Mission Directorate, Washington. Science operations are conducted at the Spitzer Science Center at Caltech, also in Pasadena. Caltech manages JPL for NASA. For more information about Spitzer, visit http://spitzer.caltech.edu/ and http://www.nasa.gov/spitzer.
Monday, November 22, 2010
The funding is part of a cooperative agreement with the Foundation for Inspiration and Recognition of Science and Technology (FIRST), a nonprofit organization in Manchester, N.H. FIRST provides students the opportunity to engage with government, industry and university experts, including those at NASA's Jet Propulsion Laboratory, Pasadena, Calif., for hands-on, realistic exposure to engineering and technical professions.
"This is the largest NASA-funded student program geared toward robotics activities," said NASA Administrator Charles Bolden. "For the next five years, approximately 25,000 students across the country will not only learn from our nation's best and brightest, but also compete and have fun at the same time."
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Friday, November 12, 2010
Stone drew a crude sketch of this scalloped, multi-stranded ring, known as the F ring, in his notebook, but with no explanation next to it. The innumerable particles comprising the broad rings are in near-circular orbits about Saturn. So, it was a surprise to find that the F ring, discovered just a year before by NASA's Pioneer 11 spacecraft, had clumps and wayward kinks. What could have created such a pattern?
"It was clear Voyager was showing us something different at Saturn," said Stone, now based at the California Institute of Technology in Pasadena. "Over and over, the spacecraft revealed so many unexpected things that it often took days, months and even years to figure them out."
The F ring curiosity was only one of many strange phenomena discovered in the Voyager close encounters with Saturn, which occurred on Nov. 12, 1980, for Voyager 1, and Aug. 25, 1981, for Voyager 2. The Voyager encounters were responsible for finding six small moons and revealing the half-young, half-old terrain of Enceladus that had to point to some kind of geological activity.
Images from the two encounters also exposed individual storms roiling the planet's atmosphere, which did not show up at all in data from Earth-based telescopes. Scientists used Voyager data to resolve a debate about whether Titan had a thick or thin atmosphere, finding that Titan was shrouded in a thick haze of hydrocarbons in a nitrogen-rich atmosphere. The finding led scientists to predict there could be seas of liquid methane and ethane on Titan's surface.
"When I look back, I realize how little we actually knew about the solar system before Voyager," Stone added. "We discovered things we didn't know were there to be discovered, time after time."
In fact, the Voyager encounters sparked so many new questions that another spacecraft, NASA's Cassini, was sent to probe those mysteries. While Voyager 1 got to within about 126,000 kilometers (78,300 miles) above Saturn's cloud tops, and Voyager 2 approached as close as about 100,800 kilometers (62,600 miles), Cassini has dipped to this altitude and somewhat lower in its orbits around Saturn since 2004.
Because of Cassini's extended journey around Saturn, scientists have found explanations for many of the mysteries first seen by Voyager. Cassini has uncovered a mechanism to explain the new terrain on Enceladus – tiger stripe fissures with jets of water vapor and organic particles. It revealed that Titan indeed does have stable lakes of liquid hydrocarbons on its surface and showed just how similar to Earth that moon really is. Data from Cassini have also resolved how two small moons discovered by Voyager – Prometheus and Pandora – tug on the F ring to create its kinked shape and wakes that form snowballs.
"Cassini is indebted to Voyager for its many fascinating discoveries and for paving the way for Cassini," said Linda Spilker, Cassini project scientist at JPL, who started her career working on Voyager from 1977 to 1989. "On Cassini, we still compare our data to Voyager's and proudly build on Voyager's heritage."
But Voyager left a few mysteries that Cassini has not yet solved. For instance, scientists first spotted a hexagonal weather pattern when they stitched together Voyager images of Saturn's north pole. Cassini has obtained higher-resolution pictures of the hexagon – which tells scientists it's a remarkably stable wave in one of the jet streams that remains 30 years later – but scientists are still not sure what forces maintain the hexagon.
Even more perplexing are the somewhat wedge-shaped, transient clouds of tiny particles that Voyager discovered orbiting in Saturn's B ring. Scientists dubbed them "spokes" because they looked like bicycle spokes. Cassini scientists have been searching for them since the spacecraft first arrived. As Saturn approached equinox, and the sun's light hit the rings edge-on, the spokes did reappear in the outer part of Saturn's B ring. But Cassini scientists are still testing their theories of what might be causing these odd features.
"The fact that we still have mysteries today goes to show how much we still have to learn about our solar system," said Suzanne Dodd, Voyager's project manager, based at JPL. "Today, the Voyager spacecraft continue as pioneers traveling toward the edge of our solar system. We can't wait for the Voyager spacecraft to enter interstellar space – true outer space – and make more unexpected discoveries."
Voyager 1, which was launched on Sept. 5, 1977, is currently about 17 billion kilometers (11 billion miles) away from the sun. It is the most distant spacecraft. Voyager 2, which was launched on Aug. 20, 1977, is currently about 14 billion kilometers (9 billion miles) away from the sun.
The Voyagers were built by JPL, which continues to operate both spacecraft. Caltech manages JPL for NASA. The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. JPL manages Cassini for NASA. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL.
More Voyager information is available at http://www.nasa.gov/voyager and http://voyager.jpl.nasa.gov .
More Cassini information is available at http://www.nasa.gov/cassini and http://saturn.jpl.nasa.gov .