October 16, 2017
Fresh Findings From Cassini
NASA's Cassini spacecraft ended its journey on Sept. 15 with an intentional plunge into the atmosphere of Saturn, but analysis continues on the mountain of data the spacecraft sent during its long life. Some of the Cassini team's freshest insights were presented during a news conference today at the American Astronomical Society Division for Planetary Science meeting in Provo, Utah.
Among the findings being shared:
-- Views from Cassini's Grand Finale show the beauty of the rings and demonstrate processes similar to those that form planets.
During Cassini's final months, the spacecraft's cameras captured views from within the gap between the planet and the rings, and the mission is releasing two new image mosaics showing the rings from that unique perspective. One view, from May 28, 2017, shows the rings emerging from behind the planet's hazy limb, while the planet itself is adorned with ring shadows. The other mosaic shows a panoramic view outward across the ringscape.
Researchers also shared a new movie of Saturn's auroras in ultraviolet light that represents the final such view from the spacecraft's Ultraviolet Imaging Spectrometer.
In addition, Cassini participating scientist and imaging team associate Matt Tiscareno of SETI Institute, Mountain View, California, provided new details about the whimsically named ring features called propellers, which are wakes in the rings created by small, unseen moonlets. The propellers are analogous to baby planets forming in disks around young stars, as they obey similar physical processes.
Tiscareno said that, in its last images of the rings (taken the day before the spacecraft's plunge into Saturn), Cassini successfully imaged all six of the propellers whose orbits were being tracked over the last several years of the mission. These objects are named for famous aviators: Blériot, Earhart, Santos-Dumont, Sikorsky, Post and Quimby. During its Ring-Grazing Orbits -- the four months of close orbits that preceeded the mission's Grand Finale -- Cassini obtained images showing swarms of smaller propellers, astounding Tiscareno and colleagues.
-- Cassini's electronic "nose" hit the jackpot, finding many surprises as it sniffed the gases in the previously unexplored space between the planet and the rings.
The spacecraft's Ion and Neutral Mass Spectrometer (INMS) returned a host of first-ever direct measurements of the components in Saturn's upper atmosphere, which stretches almost to the rings. From these observations, the team sees evidence that molecules from the rings are raining down onto the atmosphere. This influx of material from the rings was expected, but INMS data show hints of ingredients more complex than just water, which makes up the bulk of the rings' composition. In particular, the instrument detected methane, a volatile molecule that scientists would not expect to be abundant in the rings or found so high in Saturn's atmosphere. Cassini participating scientist and INMS team associate Mark Perry from the Johns Hopkins University Applied Physics Laboratory, Laurel, Maryland, says the team is busy analyzing data from the final, lowest-altitude passes, which show even more complexity and variability. The INMS observations complement those by Cassini's Cosmic Dust Analyzer instrument, which sampled solid particles in the gap during the Grand Finale.
-- Researchers continue trying to wrangle insights about the length of the planet's day from measurements of Saturn's magnetic field.
Michele Dougherty, leader of Cassini's Magnetometer team from Imperial College London, provided an update on the team's progress in trying to determine whether Saturn's magnetic field has a detectable tilt. One aim of their work is to determine the precise length of time for the planet's internal rotation, which would help researchers nail down the true length of the planet's day. Dougherty says the sensitivity of Cassini's magnetic field measurements nearly quadrupled over the course of the spacecraft's 22 Grand Finale orbits -- meaning that, if the tilt of Saturn's field is greater than 0.016 degrees, researchers should be able to detect it. An extremely small tilt is challenging to explain with scientists' current understanding of how planetary magnetic fields are generated, thus suggesting more sophisticated dynamics inside Saturn.
-- New theoretical research explains the forces that keep Saturn's rings from spreading out and dispersing. It turns out to be a group effort.
Key among the questions scientists hope to answer using data from Cassini are the age and origins of the rings. Theoretical modeling has shown that, without forces to confine them, the rings would spread out over hundreds of millions of years -- much younger than Saturn itself. This spreading happens because faster-moving particles that orbit closer to Saturn occasionally collide with slower particles on slightly farther-out orbits. When this happens, some momentum from the faster particles is transferred to the slower particles, speeding the latter up in their orbit and causing them to move farther outward. The inverse happens to the faster, inner particles.
Previous research had shown that gravitational tugs from the moon Mimas are solely responsible for halting the outward spread of Saturn's B ring -- that ring's outer edge is defined by the dark region known as the Cassini Division. Ring scientists had thought the small moon Janus was responsible for confining the outer edge of the A ring. But a new modeling study led by Radwan Tajeddine of Cornell University, Ithaca, New York, shows that the A ring's outward creep is kept in check by a confederation of moons, including Pan, Atlas, Prometheus, Pandora, Janus, Epimetheus and Mimas.
The insight was made possible by Cassini, which provided scientists with high-resolution views of intricate waves in the rings, along with precise determinations of the masses of Saturn's moons. Analysis of these data led Tajeddine and colleagues to an understanding that a cumulative effect of waves from all these moons damps the outward transfer of momentum in the A ring and confines its edge.
Tajeddine will present these results in a poster at the DPS meeting, and they will be published Wednesday in the Astrophysical Journal.
"There are whole careers to be forged in the analysis of data from Cassini," said Linda Spilker, the mission's project scientist at NASA's Jet Propulsion Laboratory, Pasadena, California. "In a sense, the work has only just begun."
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.
More information about Cassini:
https://www.nasa.gov/cassini
https://saturn.jpl.nasa.gov
News Media Contact
Preston Dyches
Jet Propulsion Laboratory, Pasadena, Calif.
818-354-7013
preston.dyches@jpl.nasa.gov
and
NASA Missions Catch First Light from a Gravitational-Wave Event
For the first time, NASA scientists have detected light tied to a gravitational-wave event,
thanks to two merging neutron stars in the galaxy NGC 4993, located about 130 million
light-years from Earth in the constellation Hydra.
Shortly after 5:41 a.m. PDT (8:41 a.m. EDT) on Aug. 17, NASA's Fermi Gamma-ray
Space Telescope picked up a pulse of high-energy light from a powerful explosion,
which was immediately reported to astronomers around the globe as a short gamma-ray burst.
The scientists at the National Science Foundation's Laser Interferometer Gravitational-wave
Observatory (LIGO) detected gravitational waves dubbed GW170817 from a pair of smashing stars
tied to the gamma-ray burst, encouraging astronomers to look for the aftermath
of the explosion. Shortly thereafter, the burst was detected as part of a follow-up analysis
by ESA's (European Space Agency's) INTEGRAL satellite.
NASA's Swift, Hubble, Chandra and Spitzer missions, along with dozens
of ground-based observatories, including the NASA-funded Pan-STARRS survey,
later captured the fading glow of the blast's expanding debris.
"This is extremely exciting science," said Paul Hertz, director of NASA's Astrophysics
Division at the agency's headquarters in Washington. "Now, for the first time, we've seen
light and gravitational waves produced by the same event. The detection
of a gravitational-wave source's light has revealed details of the event that cannot
be determined from gravitational waves alone. The multiplier effect
of study with many observatories is incredible."
Neutron stars are the crushed, leftover cores of massive stars that previously
exploded as supernovas long ago. The merging stars likely had masses between
10 and 60 percent greater than that of our Sun, but they were no wider
than Washington, D.C. The pair whirled around each other hundreds of times
a second, producing gravitational waves at the same frequency.
As they drew closer and orbited faster, the stars eventually broke apart
and merged, producing both a gamma-ray burst and a rarely seen
flare-up called a "kilonova."
"This is the one we've all been waiting for," said David Reitze, executive director
of the LIGO Laboratory at Caltech in Pasadena, California. "Neutron star mergers produce
a wide variety of light because the objects form a maelstrom
of hot debris when they collide. Merging black holes -- the types of events LIGO
and its European counterpart, Virgo, have previously seen --
very likely consume any matter around them long before they crash,
so we don't expect the same kind of light show."
"The favored explanation for short gamma-ray bursts is that they're
caused by a jet of debris moving near the speed of light produced
in the merger of neutron stars or a neutron star and a black hole,"
said Eric Burns, a member of Fermi's Gamma-ray Burst Monitor team
at NASA's Goddard Space Flight Center in Greenbelt, Maryland.
"LIGO tells us there was a merger of compact objects, and Fermi tells us
there was a short gamma-ray burst. Together, we know that what we observed
was the merging of two neutron stars, dramatically confirming the relationship."
Within hours of the initial Fermi detection, LIGO and the Virgo detector
at the European Gravitational Observatory near Pisa, Italy, greatly refined
the event's position in the sky with additional analysis of gravitational wave data.
Ground-based observatories then quickly located a new optical and infrared source --
the kilonova -- in NGC 4993.
To Fermi, this appeared to be a typical short gamma-ray burst, but it occurred
less than one-tenth as far away as any other short burst with a known distance,
making it among the faintest known. Astronomers are still trying
to figure out why this burst is so odd, and how this event relates to the more
luminous gamma-ray bursts seen at much greater distances.
NASA's Swift, Hubble and Spitzer missions followed the evolution of the kilonova
to better understand the composition of this slower-moving material,
while Chandra searched for X-rays associated with the remains of the ultra-fast jet.
When Swift turned to the galaxy shortly after Fermi's gamma-ray burst detection,
it found a bright and quickly fading ultraviolet (UV) source.
"We did not expect a kilonova to produce bright UV emission,"
said Goddard's S. Bradley Cenko, principal investigator for Swift.
"We think this was produced by the short-lived disk of debris
that powered the gamma-ray burst."
Over time, material hurled out by the jet slows and widens as it sweeps up
and heats interstellar material, producing so-called afterglow emission that includes X-rays.
But the spacecraft saw no X-rays -- a surprise for an event that produced higher-energy gamma rays.
NASA's Chandra X-ray Observatory clearly detected X-rays nine days after the source was discovered.
Scientists think the delay was a result of our viewing angle, and it took time for the jet directed toward Earth
to expand into our line of sight.
"The detection of X-rays demonstrates that neutron star mergers can form powerful
jets streaming out at near light speed," said Goddard's Eleonora Troja, who led one
of the Chandra teams and found the X-ray emission.We had to wait for nine days
to detect it because we viewed it from the side, unlike anything we had seen before."
On Aug. 22, NASA's Hubble Space Telescope began imaging the kilonova and capturing
its near-infrared spectrum, which revealed the motion and chemical composition
of the expanding debris.
"The spectrum looked exactly like how theoretical physicists had predicted the outcome
of the merger of two neutron stars would appear," said Andrew Levan at the University
of Warwick in Coventry, England, who led one of the proposals for Hubble spectral observations.
"It tied this object to the gravitational wave source beyond all reasonable doubt."
Astronomers think a kilonova's visible and infrared light primarily arises through heating
from the decay of radioactive elements formed in the neutron-rich debris.
Crashing neutron stars may be the universe's dominant source for many
of the heaviest elements, including platinum and gold.
Because of its Earth-trailing orbit, Spitzer was uniquely situated to observe
the kilonova long after the Sun moved too close to the galaxy
for other telescopes to see it. Spitzer's Sept. 30 observation captured
the longest-wavelength infrared light from the kilonova, which unveils
the quantity of heavy elements forged.
"Spitzer was the last to join the party, but it will have the final word
on how much gold was forged," says Mansi Kasliwal, Caltech assistant professor
and principal investigator of the Spitzer observing program.
Numerous scientific papers describing and interpreting these observations
have been published in Science, Nature, Physical Review Letters
and The Astrophysical Journal.
Gravitational waves were directly detected for the first time in 2015 by LIGO,
whose architects were awarded the 2017 Nobel Prize in physics for the discovery.
News Media Contact
Elizabeth Landau
Jet Propulsion Laboratory, Pasadena, CA
818-354-6425
elizabeth.landau@jpl.nasa.gov
Felicia Chou
NASA Headquarters, Washington
202-358-0257
felicia.chou@nasa.gov
Dewayne Washington
Goddard Space Flight Center, Greenbelt, Md.
301-286-0040
dewayne.a.washington@nasa.gov
Molly Porter
Marshall Space Flight Center, Huntsville, Ala.
256-544-0034
molly.a.porter@nasa.gov
2017-270
https://www.jpl.nasa.gov/news/news.php?feature=6975&utm_source=iContact&utm_medium=email&utm_campaign=NASAJPL&utm_content=ligo20171016
George Stephen Morrison (Rome (Géorgie), 7 janvier 1919 - Coronado (Californie),
17 novembre 2008) est un amiral et aviateur naval de la marine des États-Unis.
Morrison a été le commandant des forces navales américaines dans le golfe du Tonkin
au cours de l'incident du Golfe du Tonkin d'août 1964, qui a servi de prétexte à l'engagement
des États-Unis dans la guerre du Viêt Nam.
Il est le père de Jim Morrison, le chanteur du groupe de rock The Doors1,2,3.
RAPPORT DU
CITOYEN TIGNARD YANIS
ALIAS
TAY
La chouette effraie
Fresh Findings From Cassini
NASA's Cassini spacecraft ended its journey on Sept. 15 with an intentional plunge into the atmosphere of Saturn, but analysis continues on the mountain of data the spacecraft sent during its long life. Some of the Cassini team's freshest insights were presented during a news conference today at the American Astronomical Society Division for Planetary Science meeting in Provo, Utah.
Among the findings being shared:
-- Views from Cassini's Grand Finale show the beauty of the rings and demonstrate processes similar to those that form planets.
During Cassini's final months, the spacecraft's cameras captured views from within the gap between the planet and the rings, and the mission is releasing two new image mosaics showing the rings from that unique perspective. One view, from May 28, 2017, shows the rings emerging from behind the planet's hazy limb, while the planet itself is adorned with ring shadows. The other mosaic shows a panoramic view outward across the ringscape.
Researchers also shared a new movie of Saturn's auroras in ultraviolet light that represents the final such view from the spacecraft's Ultraviolet Imaging Spectrometer.
In addition, Cassini participating scientist and imaging team associate Matt Tiscareno of SETI Institute, Mountain View, California, provided new details about the whimsically named ring features called propellers, which are wakes in the rings created by small, unseen moonlets. The propellers are analogous to baby planets forming in disks around young stars, as they obey similar physical processes.
Tiscareno said that, in its last images of the rings (taken the day before the spacecraft's plunge into Saturn), Cassini successfully imaged all six of the propellers whose orbits were being tracked over the last several years of the mission. These objects are named for famous aviators: Blériot, Earhart, Santos-Dumont, Sikorsky, Post and Quimby. During its Ring-Grazing Orbits -- the four months of close orbits that preceeded the mission's Grand Finale -- Cassini obtained images showing swarms of smaller propellers, astounding Tiscareno and colleagues.
-- Cassini's electronic "nose" hit the jackpot, finding many surprises as it sniffed the gases in the previously unexplored space between the planet and the rings.
The spacecraft's Ion and Neutral Mass Spectrometer (INMS) returned a host of first-ever direct measurements of the components in Saturn's upper atmosphere, which stretches almost to the rings. From these observations, the team sees evidence that molecules from the rings are raining down onto the atmosphere. This influx of material from the rings was expected, but INMS data show hints of ingredients more complex than just water, which makes up the bulk of the rings' composition. In particular, the instrument detected methane, a volatile molecule that scientists would not expect to be abundant in the rings or found so high in Saturn's atmosphere. Cassini participating scientist and INMS team associate Mark Perry from the Johns Hopkins University Applied Physics Laboratory, Laurel, Maryland, says the team is busy analyzing data from the final, lowest-altitude passes, which show even more complexity and variability. The INMS observations complement those by Cassini's Cosmic Dust Analyzer instrument, which sampled solid particles in the gap during the Grand Finale.
-- Researchers continue trying to wrangle insights about the length of the planet's day from measurements of Saturn's magnetic field.
Michele Dougherty, leader of Cassini's Magnetometer team from Imperial College London, provided an update on the team's progress in trying to determine whether Saturn's magnetic field has a detectable tilt. One aim of their work is to determine the precise length of time for the planet's internal rotation, which would help researchers nail down the true length of the planet's day. Dougherty says the sensitivity of Cassini's magnetic field measurements nearly quadrupled over the course of the spacecraft's 22 Grand Finale orbits -- meaning that, if the tilt of Saturn's field is greater than 0.016 degrees, researchers should be able to detect it. An extremely small tilt is challenging to explain with scientists' current understanding of how planetary magnetic fields are generated, thus suggesting more sophisticated dynamics inside Saturn.
-- New theoretical research explains the forces that keep Saturn's rings from spreading out and dispersing. It turns out to be a group effort.
Key among the questions scientists hope to answer using data from Cassini are the age and origins of the rings. Theoretical modeling has shown that, without forces to confine them, the rings would spread out over hundreds of millions of years -- much younger than Saturn itself. This spreading happens because faster-moving particles that orbit closer to Saturn occasionally collide with slower particles on slightly farther-out orbits. When this happens, some momentum from the faster particles is transferred to the slower particles, speeding the latter up in their orbit and causing them to move farther outward. The inverse happens to the faster, inner particles.
Previous research had shown that gravitational tugs from the moon Mimas are solely responsible for halting the outward spread of Saturn's B ring -- that ring's outer edge is defined by the dark region known as the Cassini Division. Ring scientists had thought the small moon Janus was responsible for confining the outer edge of the A ring. But a new modeling study led by Radwan Tajeddine of Cornell University, Ithaca, New York, shows that the A ring's outward creep is kept in check by a confederation of moons, including Pan, Atlas, Prometheus, Pandora, Janus, Epimetheus and Mimas.
The insight was made possible by Cassini, which provided scientists with high-resolution views of intricate waves in the rings, along with precise determinations of the masses of Saturn's moons. Analysis of these data led Tajeddine and colleagues to an understanding that a cumulative effect of waves from all these moons damps the outward transfer of momentum in the A ring and confines its edge.
Tajeddine will present these results in a poster at the DPS meeting, and they will be published Wednesday in the Astrophysical Journal.
"There are whole careers to be forged in the analysis of data from Cassini," said Linda Spilker, the mission's project scientist at NASA's Jet Propulsion Laboratory, Pasadena, California. "In a sense, the work has only just begun."
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.
More information about Cassini:
https://www.nasa.gov/cassini
https://saturn.jpl.nasa.gov
News Media Contact
Preston Dyches
Jet Propulsion Laboratory, Pasadena, Calif.
818-354-7013
preston.dyches@jpl.nasa.gov
and
NASA Missions Catch First Light from a Gravitational-Wave Event
For the first time, NASA scientists have detected light tied to a gravitational-wave event,
thanks to two merging neutron stars in the galaxy NGC 4993, located about 130 million
light-years from Earth in the constellation Hydra.
Shortly after 5:41 a.m. PDT (8:41 a.m. EDT) on Aug. 17, NASA's Fermi Gamma-ray
Space Telescope picked up a pulse of high-energy light from a powerful explosion,
which was immediately reported to astronomers around the globe as a short gamma-ray burst.
The scientists at the National Science Foundation's Laser Interferometer Gravitational-wave
Observatory (LIGO) detected gravitational waves dubbed GW170817 from a pair of smashing stars
tied to the gamma-ray burst, encouraging astronomers to look for the aftermath
of the explosion. Shortly thereafter, the burst was detected as part of a follow-up analysis
by ESA's (European Space Agency's) INTEGRAL satellite.
NASA's Swift, Hubble, Chandra and Spitzer missions, along with dozens
of ground-based observatories, including the NASA-funded Pan-STARRS survey,
later captured the fading glow of the blast's expanding debris.
"This is extremely exciting science," said Paul Hertz, director of NASA's Astrophysics
Division at the agency's headquarters in Washington. "Now, for the first time, we've seen
light and gravitational waves produced by the same event. The detection
of a gravitational-wave source's light has revealed details of the event that cannot
be determined from gravitational waves alone. The multiplier effect
of study with many observatories is incredible."
Neutron stars are the crushed, leftover cores of massive stars that previously
exploded as supernovas long ago. The merging stars likely had masses between
10 and 60 percent greater than that of our Sun, but they were no wider
than Washington, D.C. The pair whirled around each other hundreds of times
a second, producing gravitational waves at the same frequency.
As they drew closer and orbited faster, the stars eventually broke apart
and merged, producing both a gamma-ray burst and a rarely seen
flare-up called a "kilonova."
"This is the one we've all been waiting for," said David Reitze, executive director
of the LIGO Laboratory at Caltech in Pasadena, California. "Neutron star mergers produce
a wide variety of light because the objects form a maelstrom
of hot debris when they collide. Merging black holes -- the types of events LIGO
and its European counterpart, Virgo, have previously seen --
very likely consume any matter around them long before they crash,
so we don't expect the same kind of light show."
"The favored explanation for short gamma-ray bursts is that they're
caused by a jet of debris moving near the speed of light produced
in the merger of neutron stars or a neutron star and a black hole,"
said Eric Burns, a member of Fermi's Gamma-ray Burst Monitor team
at NASA's Goddard Space Flight Center in Greenbelt, Maryland.
"LIGO tells us there was a merger of compact objects, and Fermi tells us
there was a short gamma-ray burst. Together, we know that what we observed
was the merging of two neutron stars, dramatically confirming the relationship."
Within hours of the initial Fermi detection, LIGO and the Virgo detector
at the European Gravitational Observatory near Pisa, Italy, greatly refined
the event's position in the sky with additional analysis of gravitational wave data.
Ground-based observatories then quickly located a new optical and infrared source --
the kilonova -- in NGC 4993.
To Fermi, this appeared to be a typical short gamma-ray burst, but it occurred
less than one-tenth as far away as any other short burst with a known distance,
making it among the faintest known. Astronomers are still trying
to figure out why this burst is so odd, and how this event relates to the more
luminous gamma-ray bursts seen at much greater distances.
NASA's Swift, Hubble and Spitzer missions followed the evolution of the kilonova
to better understand the composition of this slower-moving material,
while Chandra searched for X-rays associated with the remains of the ultra-fast jet.
When Swift turned to the galaxy shortly after Fermi's gamma-ray burst detection,
it found a bright and quickly fading ultraviolet (UV) source.
"We did not expect a kilonova to produce bright UV emission,"
said Goddard's S. Bradley Cenko, principal investigator for Swift.
"We think this was produced by the short-lived disk of debris
that powered the gamma-ray burst."
Over time, material hurled out by the jet slows and widens as it sweeps up
and heats interstellar material, producing so-called afterglow emission that includes X-rays.
But the spacecraft saw no X-rays -- a surprise for an event that produced higher-energy gamma rays.
NASA's Chandra X-ray Observatory clearly detected X-rays nine days after the source was discovered.
Scientists think the delay was a result of our viewing angle, and it took time for the jet directed toward Earth
to expand into our line of sight.
"The detection of X-rays demonstrates that neutron star mergers can form powerful
jets streaming out at near light speed," said Goddard's Eleonora Troja, who led one
of the Chandra teams and found the X-ray emission.We had to wait for nine days
to detect it because we viewed it from the side, unlike anything we had seen before."
On Aug. 22, NASA's Hubble Space Telescope began imaging the kilonova and capturing
its near-infrared spectrum, which revealed the motion and chemical composition
of the expanding debris.
"The spectrum looked exactly like how theoretical physicists had predicted the outcome
of the merger of two neutron stars would appear," said Andrew Levan at the University
of Warwick in Coventry, England, who led one of the proposals for Hubble spectral observations.
"It tied this object to the gravitational wave source beyond all reasonable doubt."
Astronomers think a kilonova's visible and infrared light primarily arises through heating
from the decay of radioactive elements formed in the neutron-rich debris.
Crashing neutron stars may be the universe's dominant source for many
of the heaviest elements, including platinum and gold.
Because of its Earth-trailing orbit, Spitzer was uniquely situated to observe
the kilonova long after the Sun moved too close to the galaxy
for other telescopes to see it. Spitzer's Sept. 30 observation captured
the longest-wavelength infrared light from the kilonova, which unveils
the quantity of heavy elements forged.
"Spitzer was the last to join the party, but it will have the final word
on how much gold was forged," says Mansi Kasliwal, Caltech assistant professor
and principal investigator of the Spitzer observing program.
Numerous scientific papers describing and interpreting these observations
have been published in Science, Nature, Physical Review Letters
and The Astrophysical Journal.
Gravitational waves were directly detected for the first time in 2015 by LIGO,
whose architects were awarded the 2017 Nobel Prize in physics for the discovery.
News Media Contact
Elizabeth Landau
Jet Propulsion Laboratory, Pasadena, CA
818-354-6425
elizabeth.landau@jpl.nasa.gov
Felicia Chou
NASA Headquarters, Washington
202-358-0257
felicia.chou@nasa.gov
Dewayne Washington
Goddard Space Flight Center, Greenbelt, Md.
301-286-0040
dewayne.a.washington@nasa.gov
Molly Porter
Marshall Space Flight Center, Huntsville, Ala.
256-544-0034
molly.a.porter@nasa.gov
2017-270
https://www.jpl.nasa.gov/news/news.php?feature=6975&utm_source=iContact&utm_medium=email&utm_campaign=NASAJPL&utm_content=ligo20171016
George Stephen Morrison (Rome (Géorgie), 7 janvier 1919 - Coronado (Californie),
17 novembre 2008) est un amiral et aviateur naval de la marine des États-Unis.
Morrison a été le commandant des forces navales américaines dans le golfe du Tonkin
au cours de l'incident du Golfe du Tonkin d'août 1964, qui a servi de prétexte à l'engagement
des États-Unis dans la guerre du Viêt Nam.
Il est le père de Jim Morrison, le chanteur du groupe de rock The Doors1,2,3.
RAPPORT DU
CITOYEN TIGNARD YANIS
ALIAS
TAY
La chouette effraie