Robert Picardo of The Planetary Post and Dr. Amy Mainzer from NASA JPL and deputy manager for the NEOWISE Project
discuss our efforts to look for asteroids and comets near Earth and how we plan to deflect the dangerous ones that could come our way.
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Check out the exotic sounds of Saturn as derived from the radio transmissions generated by waves in the plasma (ionized particles) between Saturn and the rings and the satellite Enceladus:
Listen: Electromagnetic Energy of Saturn, Enceladus
New research from NASA’s Cassini spacecraft’s up-close Grand Finale orbits shows a surprisingly powerful and dynamic interaction of plasma waves moving from Saturn to its rings and its moon Enceladus. The observations show for the first time that the waves travel on magnetic field lines connecting Saturn directly to Enceladus. The field lines are like an electrical circuit between the two bodies, with energy flowing back and forth.
Researchers converted the recording of plasma waves into a “whooshing” audio file that we can hear — in the same way a radio translates electromagnetic waves into music. In other words, Cassini detected electromagnetic waves in the audio frequency range — and on the ground, we can amplify and play those signals through a speaker. The recording time was compressed from 16 minutes to 28.5 seconds.
Much like air or water, plasma (the fourth state of matter) generates waves to carry energy. The Radio Plasma Wave Science (RPWS) instrument on board NASA’s Cassini spacecraft recorded intense plasma waves during one of its closest encounters to Saturn.
“Enceladus is this little generator going around Saturn, and we know it is a continuous source of energy,” said Ali Sulaiman, planetary scientist at the University of Iowa, Iowa City, and a member of the RPWS team. “Now we find that Saturn responds by launching signals in the form of plasma waves, through the circuit of magnetic field lines connecting it to Enceladus hundreds of thousands of miles away.”
Sulaiman is lead author of a pair of papers describing the findings, published recently in Geophysical Research Letters.
The interaction of Saturn and Enceladus is different from the relationship of Earth and its Moon. Enceladus is immersed in Saturn’s magnetic field and is geologically active, emitting plumes of water vapor that become ionized and fill the environment around Saturn. Our own Moon does not interact in the same way with Earth. Similar interactions take place between Saturn and its rings, as they are also very dynamic.
The recording was captured Sept. 2, 2017, two weeks before Cassini was deliberately plunged into the atmosphere of Saturn. The recording was converted by the RPWS team at the University of Iowa, led by physicist and RPWS Principal Investigator Bill Kurth.
The GRL research is available on the American Geophysical Union’s website:
The Cassini-Huygens mission is a cooperative project of NASA, ESA (European Space Agency) and the Italian Space Agency. NASA’s Jet Propulsion Laboratory, a division of Caltech in Pasadena, manages the mission for NASA’s Science Mission Directorate, Washington. JPL designed, developed and assembled the Cassini orbiter. The RPWS instrument was built by the University of Iowa, working with team members from the U.S. and several European countries.
Gretchen McCartney
Jet Propulsion Laboratory, Pasadena, California
818-393-6215
Gretchen.P.McCartney@jpl.nasa.gov
Dwayne Brown / JoAnna Wendel
NASA Headquarters, Washington
202-358-1726 / 202-358-1003
dwayne.c.brown@nasa.gov / joanna.r.wendel@nasa.gov
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The latest from the Dawn probe orbiting low over the dwarf planet Ceres in the asteroid belt:
Dawn’s Latest Orbit Reveals Dramatic New Views of Occator Crater
NASA’s Dawn spacecraft reached its lowest-ever and final orbit around dwarf planet Ceres on June 6 and has been returning thousands of stunning images and other data.
The flight team maneuvered the spacecraft into an orbit that dives 22 miles (35 kilometers) above the surface of Ceres and viewed Occator Crater, site of the famous bright deposits, and other intriguing regions. In more than three years of orbiting Ceres, Dawn’s lowest altitude before this month was 240 miles (385 kilometers), so the data from this current orbit bring the dwarf planet into much sharper focus.
These low orbits have revealed unprecedented details of the relationships between bright and dark materials in the region of Vinalia Faculae. Dawn’s visible and infrared mapping spectrometer had previously found the bright deposits to be made of sodium carbonate, a material commonly found in evaporite deposits on Earth. Last week Dawn fired its ion engine, possibly for the final time, to fly nearer Cerealia Facula, the large deposit of sodium carbonate in the center of Occator Crater.
“Acquiring these spectacular pictures has been one of the greatest challenges in Dawn’s extraordinary extraterrestrial expedition, and the results are better than we had ever hoped,” said Dawn’s chief engineer and project manager, Marc Rayman, of NASA’s Jet Propulsion Laboratory, Pasadena, California. “Dawn is like a master artist, adding rich details to the otherworldly beauty in its intimate portrait of Ceres.”
The wealth of information contained in these images, and more that are planned in the coming weeks, will help address key, open questions about the origin of the faculae, the largest deposits of carbonates observed thus far outside Earth, and possibly Mars. In particular, scientists have been wondering how that material was exposed, either from a shallow, sub-surface reservoir of mineral-laden water, or from a deeper source of brines (liquid water enriched in salts) percolating upward through fractures.
And the low-altitude observations obtained with Dawn’s other instruments, a gamma ray and neutron detector and a visible and infrared mapping spectrometer, will reveal the composition of Ceres at finer scale, shedding new light on the origin of the materials found across Ceres’ surface. New gravity measurements also may reveal details of the subsurface.
“The first views of Ceres obtained by Dawn beckoned us with a single, blinding bright spot,” said Carol Raymond of JPL, Dawn’s principal investigator. “Unraveling the nature and history of this fascinating dwarf planet during the course of Dawn’s extended stay at Ceres has been thrilling, and it is especially fitting that Dawn’s last act will provide rich new data sets to test those theories.”
See more images from Dawn’s low orbits here.
Read more details about Dawn’s recent orbits in Rayman’s Dawn Journal.
The Dawn mission is managed by JPL for NASA’s Science Mission Directorate in Washington. Dawn is a project of the directorate’s Discovery Program, managed by NASA’s Marshall Space Flight Center in Huntsville, Alabama. JPL is responsible for overall Dawn mission science. Orbital ATK Inc., in Dulles, Virginia, designed and built the spacecraft. The German Aerospace Center, Max Planck Institute for Solar System Research, Italian Space Agency and Italian National Astrophysical Institute are international partners on the mission team.
For a complete list of mission participants, visit: https://dawn.jpl.nasa.gov/mission
More information about Dawn is available at the following sites:
Gretchen McCartney
Jet Propulsion Laboratory, Pasadena, Calif.
818-393-6215
gretchen.p.mccartney@jpl.nasa.gov
Dwayne Brown / JoAnna Wendel
NASA Headquarters, Washington
202-358-1726 / 202-358-1003
dwayne.c.brown@nasa.gov / joanna.r.wendel@nasa.gov
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The planet-wide dust cloud on Mars continues and may last another month or two. Opportunity rover remains in a deep freeze mode while the sun is blocked from powering its solar panels but Curiosity‘s nuclear power planet keeps it running regardless of the weather. Here is an update on the storm from NASA JPL:
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These processed images of Jupiter from the Juno probe never get old. Here is a new one:
This image captures swirling cloud belts and tumultuous vortices within Jupiter’s northern hemisphere.
NASA’s Juno spacecraft took this color-enhanced image at 10:23 p.m. PDT on May 23, 2018 (1:23 a.m. EDT on May 24), as the spacecraft performed its 13th close flyby of Jupiter. At the time, Juno was about 9,600 miles (15,500 kilometers) from the planet’s cloud tops, above a northern latitude of 56 degrees.
The region seen here is somewhat chaotic and turbulent, given the various swirling cloud formations. In general, the darker cloud material is deeper in Jupiter’s atmosphere, while bright cloud material is high. The bright clouds are most likely ammonia or ammonia and water, mixed with a sprinkling of unknown chemical ingredients.
A bright oval at bottom center stands out in the scene. This feature appears uniformly white in ground-based telescope observations. However, with JunoCam we can observe the fine-scale structure within this weather system, including additional structures within it. There is not significant motion apparent in the interior of this feature; like the Great Red Spot, its winds probably slows down greatly toward the center.
Citizen scientists Gerald Eichstädt and Seán Doran created this image using data from the spacecraft’s JunoCam imager.
JunoCam’s raw images are available for the public to peruse and process into image products at www.missionjuno.swri.edu/junocam
More information about Juno is at: https://www.nasa.gov/juno and http://missionjuno.swri.edu
Image Credits: NASA/JPL-Caltech/SwRI/MSSS/Gerald Eichstädt /Seán Doran
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This image captures the intensity of the jets and vortices in Jupiter’s North North Temperate Belt.
NASA’s Juno spacecraft took this color-enhanced image at 10:31 p.m. PDT on May 23, 2018 (1:31 a.m. EDT on May 24), as Juno performed its 13th close flyby of Jupiter. At the time, the spacecraft was about 4,900 miles (7,900 kilometers) from the tops of the clouds of the gas giant planet at a northern latitude of about 41 degrees. The view is oriented with south on Jupiter toward upper left and north toward lower right.
The North North Temperate Belt is the prominent reddish-orange band left of center. It rotates in the same direction as the planet and is predominantly cyclonic, which in the northern hemisphere means its features spin in a counter-clockwise direction. Within the belt are two gray-colored anticyclones.
To the left of the belt is a brighter band (the North North Temperate Zone) with high clouds whose vertical relief is accentuated by the low angle of sunlight near the terminator. These clouds are likely made of ammonia-ice crystals, or possibly a combination of ammonia ice and water. Although the region as a whole appears chaotic, there is an alternating pattern of rotating, lighter-colored features on the zone’s north and south sides.
Scientists think the large-scale dark regions are places where the clouds are deeper, based on infrared observations made at the same time by Juno’s JIRAM experiment and Earth-based supporting observations. Those observations show warmer, and thus deeper, thermal emission from these regions.
To the right of the bright zone, and farther north on the planet, Jupiter’s striking banded structure becomes less evident and a region of individual cyclones can be seen, interspersed with smaller, darker anticyclones.
Citizen scientist Kevin M. Gill created this image using data from the spacecraft’s JunoCam imager.
JunoCam’s raw images are available for the public to peruse and process into image products at: www.missionjuno.swri.edu/junocam
More information about Juno is at: https://www.nasa.gov/juno and http://missionjuno.swri.edu
Image Credits: NASA/JPL-Caltech/SwRI/MSSS/Kevin M. Gill
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