Post by Andrei Tchentchik on Aug 19, 2020 15:35:03 GMT 2
(.#481).- The Parker Solar Probe probe is upsetting the puzzle of the solar corona.
The Parker Solar Probe is upsetting the puzzle of the solar corona.
Laurent Sacco, Journalist.
Published on 06/12/2019 - Modified on 07/12/2019
Parker Solar Probe, the space probe responsible for unlocking the mysteries of the Sun, made three of the 24 planned passages in parts of the solar atmosphere never explored. On December 4, 2019, four articles in the journal Nature describe what scientists have learned and there are surprises.
Solar physicists analyzing the results of the Parker Solar Probe mission (some are French and members of the CNRS), the first space mission to literally enter the solar atmosphere successfully launched on August 12, 2018 from Cape Canaveral, have just published in Nature their conclusions about the first data collected by the NASA probe. Recall that the two main objectives of this mission are to better understand the enigma of heating the solar corona and to unlock the secrets of the production of the solar wind for the constitution of a reliable space meteorology.
To understand what the enigma of heating the solar corona consists of, imagine what your amazement would be if you suddenly discovered that it is possible to boil water by placing a pan on a block of ice! The Sun's surface temperature is around 6,000 Kelvin, but that of the crown - the main part of its atmosphere, which spans millions of kilometers - exceeds one million degrees. The fact has been known for more than 70 years and the idea even came that it was perhaps a violation of the second principle of thermodynamics, which says that heat always propagates spontaneously from a hot body to a cold body. It's hard to believe because this principle is one of the pillars of physics, except, possibly, in the nanoworld.
VIDÉO euronews
Parker probe: a trip closer to the sun
A presentation of the Parker Solar Probe mission. Over the duration of the probe's mission, it will touch the Sun 24 times, reaching only 8.8 solar rays from its surface. © euronews
Solar meteorology to protect the Earth
However, there were far less revolutionary possible solutions, as began to be understood by great astrophysicists like Evry Schatzman in the 1940s. Waves rising from the surface of the Sun can heat the crown. Among the candidates proposed very early were the waves of Alfvén, discovered by the Swedish Nobel Prize winner in physics Hannes Alfvén by coupling the Maxwell equations of electromagnetism with the Navier-Stokes equations of hydrodynamics. In recent decades, it has been repeatedly reported that significant breakthroughs have been made in solving the crown conundrum, but there is still work to be done to make sure that we really understand what is going on. Caution is necessary because we know that the Universe is often surprising, thwarting the theories that seemed too plausible not to be true.
To understand why the establishment of a real solar meteorology, capable of predicting the occurrences of solar flares and coronal mass ejections which can accompany them, is important, we must remember that our civilization is constantly more dependent on electrical technologies and information, whether in the form of ground electrical and telecommunications networks, than with orbiting satellites. Even if on average a solar storm only occurs once a year, we know that the magnetic disturbances generated could be so violent that they could go as far as causing a shutdown of the Web or a collision between airliners due an error on their GPS signals. Satellites are also vulnerable to so-called killer electrons. To limit the consequences of solar storms by taking adequate measures, it would therefore be necessary to determine their amplitudes and when they arrive on Earth or in contact with interplanetary travelers, for example Martian settlers in transit.
VIDÉO :
NASA ScienceCasts: Effects of the Solar Wind
Solar flares and their dangers. To get a fairly faithful translation into French, click on the white rectangle at the bottom right. English subtitles should then appear. Then click on the nut to the right of the rectangle, then on "Subtitles" and finally on "Translate automatically". Choose "French". © ScienceAtNasa
Even if the electrical networks are better protected today, it is good to remember that on March 13, 1989, in Quebec, a solar flare caused the power plants to shutdown for nine hours. We know that the Sun is capable of much worse anger because in 1859 the greatest solar storm known to mankind occurred. Sometimes called the Carrington event, after the British astronomer who observed a spectacular increase in activity on the surface of the Sun, it was accompanied by polar auroras visible even in the Caribbean and the United States where the you could then read the newspaper in the middle of the night in Boston.
To achieve its objectives, the Parker Solar Probe mission had to move closer to the solar corona to measure as closely as possible the characteristics of the solar wind whose existence had been predicted in 1957 by the American astrophysicist Eugene Parker, but which was discovered in the interplanetary space by the Russian mission Luna 1 in January 1959. Parker Solar Probe instruments were to measure the local electric and magnetic fields present in the plasma of the solar wind as well as the velocities of the particles in this plasma. For the record, this plasma is mainly made up of protons and electrons but also helium nuclei, and to a lesser extent ions corresponding to many elements known on Earth.
In the vicinity of the Earth, the solar wind behaves like a flow of particles emitted radially, a little like the stable and laminar flow of a fluid. But astrophysicists knew that closer to the Sun, things had to be different, the whole question was to what extent. Indeed, the Sun turns and it generates a magnetic field whose field lines must entrain the charged particles, so that the solar wind must also exhibit a rotation.
Closer to the solar corona, we could also hope to surprise phenomena providing information on the acceleration mechanisms of the particles of the solar wind and on the heating of the solar corona. In the vicinity of Earth, the trace of these phenomena must have been largely erased by the journey from the Sun.
VIDÉO :
Parker Solar Probe findings : Rotational solar...
The Parker Solar Probe mission revealed a much more turbulent solar wind than expected at its source, as Justin Kasper explains. To get a fairly faithful translation into French, click on the white rectangle at the bottom right. English subtitles should then appear. Then click on the nut to the right of the rectangle, then on "Subtitles" and finally on "Translate automatically". Choose "French". © Michigan Engineering
A more chaotic and turbulent solar wind than expected
The researchers were not disappointed, as explained in a Nasa press release, Stuart Bale, of the University of California at Berkeley, in charge of the instrument suite called FIELDS by Parker Solar Probe: "The complexity was amazing when we started looking at the data ... Now I'm used to it. But when I show them to my colleagues for the first time, they are simply amazed. ".
Solar physicists have indeed highlighted in Parker Solar Probe measurements that locally and transiently (from a few seconds to a few minutes) the magnetic field lines could bend to the point of pointing towards the Sun. They also note the appearance of jets of matter where the velocities of the particles are higher, so that it is clear that the solar wind is much more impulsive and unstable than what we see near the Earth.
Justin Kasper, a colleague from Stuart Bale at the University of Michigan at Ann Arbor, but who directs the team in charge of another instrument, Sweap, is also surprised at the implications of the data obtained concerning the rotation of the solar wind. and the behavior of the Alfven waves therein. The researcher explains that "These waves have been seen in the solar wind since the start of the space age, and we assumed that the power of these waves would increase as they approach the Sun, but we did not expect to see them organize themselves into these structured and coherent peaks of speed ... This will radically change our theories on how the corona and the solar wind are heated”
Kapser mentions another surprise, this one concerns the distance at which we expected to see the rotation of the solar wind: "To our surprise, as we approach the Sun, we have already detected significant rotational flows - 10 to 20 times higher than those predicted by standard models of the Sun ... So we are missing something fundamental in theories concerning the Sun and how the solar wind escapes ... This has enormous implications. Space weather forecasts will need to account for these flows if we are to be able to predict whether a coronal mass ejection will hit Earth or astronauts heading to the Moon or Mars. ".
VIDÉO Nasa Goddard
5 New Discoveries from NASA’s Parker Solar...
A presentation of the first discoveries of the Parker Solar Probe mission. To get a fairly faithful translation into French, click on the white rectangle at the bottom right. English subtitles should then appear. Then click on the nut to the right of the rectangle, then on "Subtitles" and finally on "Translate automatically". Choose "French". © Nasa Goddard
Evaporation of zodiacal dust
Parker Solar Probe also provided information on zodiacal dust, that is, interplanetary dust found in the ecliptic plane around the Sun that is the source of zodiacal light. This was the thesis topic of Brian May, the legendary guitarist of the Queen group, a thesis he completed in 2008, which makes Brian May a doctor of astrophysics.
This dust in the Solar System has diverse origins and sources. It may be that left by its formation or coming from interstellar space but we also know that the degassing of comets approaching the Sun and collisions between asteroids, in the famous main belt between Mars and Jupiter, make contributions very important.
It was expected that at a distance close enough to the Sun the temperature would be so high that it would cause the vaporization of this dust, which would lead to the formation of an internal disc which would be devoid of it. Now, determining precisely where this limit is can provide information on the composition of the dust itself and indicate how the planets were formed in the young Solar System.
This is precisely what Parker Solar Probe has done by detecting the first signs of evaporation of this dust, a phenomenon which must continue regularly as we approach our star, so that the probe should finally observe the edge of the region where evaporation is complete in 2020.
The zodiacal light is the reflection of the Sun's rays on the microscopic particles of zodiacal dust wandering between the planets of the Solar System in the vestige of its protoplanetary disc. It looks like a pale arch-like glow as seen here in the Atacama Desert. © ESO, Y. Beletsky
WHAT YOU MUST REMEMBER
• The Parker Solar Probe probe was launched on August 12, 2018. It will approach as close to the Sun as technology allows.
• In 2024, in an elliptical orbit, it will approach less than six million kilometers from the "surface" of the Sun.
• With her four instruments, she will study the solar corona where the solar wind is born, discovered by Eugene N. Parker.
• Its goal is to better understand the Sun and its atmosphere to predict solar flares and allow better protection from it. Our electronic systems are indeed sensitive to it.
• It showed that at the start of the solar corona, the solar wind was more turbulent and chaotic than expected.
F I N .
The Parker Solar Probe is upsetting the puzzle of the solar corona.
Laurent Sacco, Journalist.
Published on 06/12/2019 - Modified on 07/12/2019
Parker Solar Probe, the space probe responsible for unlocking the mysteries of the Sun, made three of the 24 planned passages in parts of the solar atmosphere never explored. On December 4, 2019, four articles in the journal Nature describe what scientists have learned and there are surprises.
Solar physicists analyzing the results of the Parker Solar Probe mission (some are French and members of the CNRS), the first space mission to literally enter the solar atmosphere successfully launched on August 12, 2018 from Cape Canaveral, have just published in Nature their conclusions about the first data collected by the NASA probe. Recall that the two main objectives of this mission are to better understand the enigma of heating the solar corona and to unlock the secrets of the production of the solar wind for the constitution of a reliable space meteorology.
To understand what the enigma of heating the solar corona consists of, imagine what your amazement would be if you suddenly discovered that it is possible to boil water by placing a pan on a block of ice! The Sun's surface temperature is around 6,000 Kelvin, but that of the crown - the main part of its atmosphere, which spans millions of kilometers - exceeds one million degrees. The fact has been known for more than 70 years and the idea even came that it was perhaps a violation of the second principle of thermodynamics, which says that heat always propagates spontaneously from a hot body to a cold body. It's hard to believe because this principle is one of the pillars of physics, except, possibly, in the nanoworld.
VIDÉO euronews
Parker probe: a trip closer to the sun
A presentation of the Parker Solar Probe mission. Over the duration of the probe's mission, it will touch the Sun 24 times, reaching only 8.8 solar rays from its surface. © euronews
Solar meteorology to protect the Earth
However, there were far less revolutionary possible solutions, as began to be understood by great astrophysicists like Evry Schatzman in the 1940s. Waves rising from the surface of the Sun can heat the crown. Among the candidates proposed very early were the waves of Alfvén, discovered by the Swedish Nobel Prize winner in physics Hannes Alfvén by coupling the Maxwell equations of electromagnetism with the Navier-Stokes equations of hydrodynamics. In recent decades, it has been repeatedly reported that significant breakthroughs have been made in solving the crown conundrum, but there is still work to be done to make sure that we really understand what is going on. Caution is necessary because we know that the Universe is often surprising, thwarting the theories that seemed too plausible not to be true.
To understand why the establishment of a real solar meteorology, capable of predicting the occurrences of solar flares and coronal mass ejections which can accompany them, is important, we must remember that our civilization is constantly more dependent on electrical technologies and information, whether in the form of ground electrical and telecommunications networks, than with orbiting satellites. Even if on average a solar storm only occurs once a year, we know that the magnetic disturbances generated could be so violent that they could go as far as causing a shutdown of the Web or a collision between airliners due an error on their GPS signals. Satellites are also vulnerable to so-called killer electrons. To limit the consequences of solar storms by taking adequate measures, it would therefore be necessary to determine their amplitudes and when they arrive on Earth or in contact with interplanetary travelers, for example Martian settlers in transit.
VIDÉO :
NASA ScienceCasts: Effects of the Solar Wind
Solar flares and their dangers. To get a fairly faithful translation into French, click on the white rectangle at the bottom right. English subtitles should then appear. Then click on the nut to the right of the rectangle, then on "Subtitles" and finally on "Translate automatically". Choose "French". © ScienceAtNasa
Even if the electrical networks are better protected today, it is good to remember that on March 13, 1989, in Quebec, a solar flare caused the power plants to shutdown for nine hours. We know that the Sun is capable of much worse anger because in 1859 the greatest solar storm known to mankind occurred. Sometimes called the Carrington event, after the British astronomer who observed a spectacular increase in activity on the surface of the Sun, it was accompanied by polar auroras visible even in the Caribbean and the United States where the you could then read the newspaper in the middle of the night in Boston.
To achieve its objectives, the Parker Solar Probe mission had to move closer to the solar corona to measure as closely as possible the characteristics of the solar wind whose existence had been predicted in 1957 by the American astrophysicist Eugene Parker, but which was discovered in the interplanetary space by the Russian mission Luna 1 in January 1959. Parker Solar Probe instruments were to measure the local electric and magnetic fields present in the plasma of the solar wind as well as the velocities of the particles in this plasma. For the record, this plasma is mainly made up of protons and electrons but also helium nuclei, and to a lesser extent ions corresponding to many elements known on Earth.
In the vicinity of the Earth, the solar wind behaves like a flow of particles emitted radially, a little like the stable and laminar flow of a fluid. But astrophysicists knew that closer to the Sun, things had to be different, the whole question was to what extent. Indeed, the Sun turns and it generates a magnetic field whose field lines must entrain the charged particles, so that the solar wind must also exhibit a rotation.
Closer to the solar corona, we could also hope to surprise phenomena providing information on the acceleration mechanisms of the particles of the solar wind and on the heating of the solar corona. In the vicinity of Earth, the trace of these phenomena must have been largely erased by the journey from the Sun.
VIDÉO :
Parker Solar Probe findings : Rotational solar...
The Parker Solar Probe mission revealed a much more turbulent solar wind than expected at its source, as Justin Kasper explains. To get a fairly faithful translation into French, click on the white rectangle at the bottom right. English subtitles should then appear. Then click on the nut to the right of the rectangle, then on "Subtitles" and finally on "Translate automatically". Choose "French". © Michigan Engineering
A more chaotic and turbulent solar wind than expected
The researchers were not disappointed, as explained in a Nasa press release, Stuart Bale, of the University of California at Berkeley, in charge of the instrument suite called FIELDS by Parker Solar Probe: "The complexity was amazing when we started looking at the data ... Now I'm used to it. But when I show them to my colleagues for the first time, they are simply amazed. ".
Solar physicists have indeed highlighted in Parker Solar Probe measurements that locally and transiently (from a few seconds to a few minutes) the magnetic field lines could bend to the point of pointing towards the Sun. They also note the appearance of jets of matter where the velocities of the particles are higher, so that it is clear that the solar wind is much more impulsive and unstable than what we see near the Earth.
Justin Kasper, a colleague from Stuart Bale at the University of Michigan at Ann Arbor, but who directs the team in charge of another instrument, Sweap, is also surprised at the implications of the data obtained concerning the rotation of the solar wind. and the behavior of the Alfven waves therein. The researcher explains that "These waves have been seen in the solar wind since the start of the space age, and we assumed that the power of these waves would increase as they approach the Sun, but we did not expect to see them organize themselves into these structured and coherent peaks of speed ... This will radically change our theories on how the corona and the solar wind are heated”
Kapser mentions another surprise, this one concerns the distance at which we expected to see the rotation of the solar wind: "To our surprise, as we approach the Sun, we have already detected significant rotational flows - 10 to 20 times higher than those predicted by standard models of the Sun ... So we are missing something fundamental in theories concerning the Sun and how the solar wind escapes ... This has enormous implications. Space weather forecasts will need to account for these flows if we are to be able to predict whether a coronal mass ejection will hit Earth or astronauts heading to the Moon or Mars. ".
VIDÉO Nasa Goddard
5 New Discoveries from NASA’s Parker Solar...
A presentation of the first discoveries of the Parker Solar Probe mission. To get a fairly faithful translation into French, click on the white rectangle at the bottom right. English subtitles should then appear. Then click on the nut to the right of the rectangle, then on "Subtitles" and finally on "Translate automatically". Choose "French". © Nasa Goddard
Evaporation of zodiacal dust
Parker Solar Probe also provided information on zodiacal dust, that is, interplanetary dust found in the ecliptic plane around the Sun that is the source of zodiacal light. This was the thesis topic of Brian May, the legendary guitarist of the Queen group, a thesis he completed in 2008, which makes Brian May a doctor of astrophysics.
This dust in the Solar System has diverse origins and sources. It may be that left by its formation or coming from interstellar space but we also know that the degassing of comets approaching the Sun and collisions between asteroids, in the famous main belt between Mars and Jupiter, make contributions very important.
It was expected that at a distance close enough to the Sun the temperature would be so high that it would cause the vaporization of this dust, which would lead to the formation of an internal disc which would be devoid of it. Now, determining precisely where this limit is can provide information on the composition of the dust itself and indicate how the planets were formed in the young Solar System.
This is precisely what Parker Solar Probe has done by detecting the first signs of evaporation of this dust, a phenomenon which must continue regularly as we approach our star, so that the probe should finally observe the edge of the region where evaporation is complete in 2020.
The zodiacal light is the reflection of the Sun's rays on the microscopic particles of zodiacal dust wandering between the planets of the Solar System in the vestige of its protoplanetary disc. It looks like a pale arch-like glow as seen here in the Atacama Desert. © ESO, Y. Beletsky
WHAT YOU MUST REMEMBER
• The Parker Solar Probe probe was launched on August 12, 2018. It will approach as close to the Sun as technology allows.
• In 2024, in an elliptical orbit, it will approach less than six million kilometers from the "surface" of the Sun.
• With her four instruments, she will study the solar corona where the solar wind is born, discovered by Eugene N. Parker.
• Its goal is to better understand the Sun and its atmosphere to predict solar flares and allow better protection from it. Our electronic systems are indeed sensitive to it.
• It showed that at the start of the solar corona, the solar wind was more turbulent and chaotic than expected.
F I N .
