- 3286 - SUN - exploring the Sun? - The Sun plays a central role in shaping space around us. Its massive magnetic field stretches far beyond Pluto, paving a superhighway for charged solar particles known as the solar wind. When bursts of solar wind hit Earth, they can spark space weather storms that interfere with our GPS and communications satellites and can even threaten astronauts.
--------------------- 3286 - SUN - exploring the Sun?
- A new spacecraft is journeying to the Sun to snap the first pictures of the Sun's north and south poles. The “Solar Orbiter“ was launched from Cape Canaveral on Feb. 7, 2020.
- Up until Solar Orbiter, all solar imaging instruments have been within the ecliptic plane. This space probe will be able to look down on the Sun from above.
-
- To prepare for arriving solar storms that started again in 2021scientists monitor the Sun's magnetic field. Their techniques work best with a straight-on view; the steeper the viewing angle, the noisier the data. The sidelong glimpse we get of the Sun's poles from within the ecliptic plane leaves major gaps in the data.
-
- The Sun's poles may also explain centuries-old observations. In 1843, German astronomer Samuel Heinrich Schwabe discovered that the number of sunspots which are dark blotches on the Sun's surface marking strong magnetic fields that waxes and wanes in a repeating pattern.
-
- Today, we know it as the approximately-11-year solar cycle in which the Sun transitions between solar maximum, when sunspots proliferate and the Sun is active and turbulent, and solar minimum, when they're fewer and it's calmer.
-
- The Solar Orbiter will pass inside the orbit of Mercury carrying four “in situ” instruments and six remote-sensing imagers, which see the Sun from afar. After years of technology development, it will be the closest any Sun-facing cameras have ever gotten to the Sun.
-
- Over the mission's seven year lifetime, Solar Orbiter will reach an inclination of 24 degrees above the Sun's equator, increasing to 33 degrees with an additional three years of extended mission operations. At closest approach the spacecraft will pass within 26 million miles of the Sun.
-
- To beat the heat, Solar Orbiter has a custom-designed titanium heat shield with a calcium phosphate coating that withstands temperatures over 900 degrees Fahrenheit which is thirteen times the solar heating faced by spacecraft in Earth orbit.
-
- Five of the remote-sensing instruments look at the Sun through peepholes in that heat shield; one observes the solar wind out to the side.
Solar Orbiter is following on August 2018's launch of “Parker Solar Probe“. Parker has completed four close solar passes and will fly within four million miles of the Sun at closest approach.
-
- The two spacecraft will work together: As Parker samples solar particles up close, Solar Orbiter will capture imagery from farther away, contextualizing the observations. The two spacecraft will also occasionally align to measure the same magnetic field lines or streams of solar wind at different times.
-
- Continued analysis of Parker Solar Probe data is starting to create a clearer picture of the sun’s magnetic activity, which may bolster our ability to predict dangerous solar events.
-
- Sensors aboard the spacecraft have produced data suggesting:
-
--------------------- The sun’s atmosphere, composed of plasma and magnetic fields, moves in a general global circulation pattern. Parker Solar Probe can observe a small section at any given time.
-
-------------------- Close to the sun, solar wind, the outward stream of charged particles from the surface, is embedded with abrupt changes in magnetic field direction, called switchbacks, along which the solar wind flows at an accelerated speed.
-
-------------------- The global coronal magnetic field slides over the surface of the sun via a process called interchange reconnection, when closed loops of magnetic field sprouting from the sun’s surface explosively realign with open magnetic field lines that extend out into the solar system.
-
- Defining that mechanism is key to predicting when a transition from slow to fast solar wind is going to strike Earth and create a geomagnetic storm. The “heliosphere” is the region of space, including our solar system, that the solar wind influences.
-
------------------- In different areas of the corona, open magnetic lines that stretch from the surface of the sun out into space should circulate in a closed pattern, with motions both in the direction of and opposite to the sun’s rotation.
-
- As Parker Solar Probe continues to move closer to the sun, the mission will provide ample opportunity to test and validate predictions by the theory.
designed, built and operates the spacecraft
-
- The first images from Solar Orbiter have revealed omnipresent miniature solar flares, dubbed 'campfires', near the surface of our closest star.
- The Solar Orbiter carries six remote-sensing instruments, or telescopes, that image the Sun and its surroundings, and four ‘in situ’ instruments that monitor the environment around the spacecraft. By comparing the data from both sets of instruments, scientists will get insights into the generation of the solar wind, the stream of charged particles from the Sun that influences the entire Solar System.
-
- The campfires were captured by the “Extreme Ultraviolet Imager” (EUI) from Solar Orbiter's first perihelion, the point in its elliptical orbit closest to the Sun. At that time, the spacecraft was only 77 million kilometers away from the Sun, about half the distance between Earth and the star.
-
- The campfires are little relatives of the solar flares that we can observe from Earth, million or billion times smaller. The scientists do not know yet whether the campfires are just tiny versions of big flares, or whether they are driven by different mechanisms. There are already theories that these miniature flares could be contributing to one of the most mysterious phenomena on the Sun, the “coronal heating“.
-
- The solar corona is the outermost layer of the Sun's atmosphere that extends millions of kilometers into outer space. Its temperature is more than a million degrees Celsius, which is orders of magnitude hotter than the surface of the Sun, a 'cool' 5500 °C. After many decades of studies, the physical mechanisms that heat the corona are still not fully understood, but identifying them is considered the 'holy grail' of solar physics.
-
- The “Polarimetric and Helioseismic Imager” (PHI) is another cutting-edge instrument aboard Solar Orbiter. It makes high-resolution measurements of the magnetic field lines on the surface of the Sun. It is designed to monitor active regions on the Sun, areas with especially strong magnetic fields, which can give birth to solar flares.
-
- During solar flares, the Sun releases bursts of energetic particles that enhance the solar wind that constantly emanates from the star into the surrounding space. When these particles interact with Earth's magnetosphere, they can cause magnetic storms that can disrupt telecommunication networks and power grids on the ground.
-
- Right now, 2021. we are in the part of the 11-year solar cycle when the Sun is very quiet. But because Solar Orbiter is at a different angle to the Sun than Earth, we could actually see one active region that wasn't observable from Earth. That is a first. We have never been able to measure the magnetic field at the back of the Sun.
-
- The “magneto grams“, showing how the strength of the solar magnetic field varies across the Sun's surface, could be then compared with the measurements from the in situ instruments.
-
- The four in situ instruments on Solar Orbiter then characterize the magnetic field lines and solar wind as it passes the spacecraft. Using this information, we can estimate where on the Sun that particular part of the solar wind was emitted, and then use the full instrument set of the mission to reveal and understand the physical processes operating in the different regions on the Sun which lead to solar wind formation.
-
- Solar Orbiter has started a grand tour of the inner Solar System, and will get much closer to the Sun within less than two years. Ultimately, it will get as close as 42 million km, which is almost a quarter of the distance from Sun to Earth. Besides solar flares Solar eclipses are another opportunity to study the Sun.
-
- Isaac Newton figured out something absolutely remarkable about gravity that no one else had ever realized: that it's universal.
-
- According to Isaac himself, the thought struck him when he watched an apple fall from a tree. He saw the apple fall in a straight line toward the Earth. He saw the apple accelerate from being still to moving. And all accelerations require a force. So, the Earth was applying a force to the apple even though it wasn't touching it.
-
- Isaac also knew that every action has an equal and opposite reaction. If the Earth is applying a force to accelerate the apple, then the apple must be applying a force to accelerate the Earth. Whatever this force of gravity is, it must be mutual and in both directions.
-
- The reason the apple moves more than the Earth is because the mass of the Earth is so much greater. It just appears like that apple is doing all the moving and the Earth is doing all the work, when in Newton's suddenly much clearer vision, all things were equal when it comes to forces.
-
- So, if the Earth is applying gravity to the apple and the apple is applying gravity to the Earth, then this force of gravity must be operating with all pairs of objects simultaneously all across the universe. In other words, gravity must be universal.
-
- Newton worked out the implications of this newfound universal force of gravity, and instantly many things clicked into place. He was able to predict the speed of the moon in its orbit. He was able to derive Kepler's laws from much simpler principles. He was able to explain the motions of all the planets and all the moons around those planets.
-
- Kepler’s writings sat there for years until one of his friends, Edmond Halley, started agitating for him to publish it. Apparently, for Newton, unlocking the secrets of universal gravity was just an idle afternoon pastime and not something worthy of serious academic interest. But Halley knew better. He constantly pressed Newton until he finally published his work.
-
- Edmond Halley then took this theory of universal gravitation and began solving almost every single problem known to plague astronomers. Most notably, he figured out the regular pattern of a particular comet that now bears his name by digging into the historical records and using that data to feed into calculations of a prediction of its reappearance.
-
- By digging into the ancient records, Halley was able to predict an upcoming total solar eclipse over his home city of London. Using Newton's theory of universal gravitation, Halley predicted the eclipse of May 3, 1715, to an accuracy of a scant four minutes.
-
- Without any calculator or computer. Just using historical records and Newton's laws, Halley nailed the first-ever accurate prediction of a solar eclipse.
-
- When the moon takes on a reddish color, or when the sun's corona shines like a glowing ring aloft in the sky, it's hard to ignore the sight. Lunar and solar eclipses have enchanted and even frightened humans for thousands of years.
-
- Eclipses aren't limited to one part of the world. In fact, there will be 20 lunar and solar eclipses traversing different places on Earth from now until the next North American cross-continental total solar eclipse on April 8, 2024.
-
- September 30, 2021 SUN - exploring the Sun? 3286
----------------------------------------------------------------------------------------
----- Comments appreciated and Pass it on to whomever is interested. ----
--- Some reviews are at: -------------- http://jdetrick.blogspot.com -----
-- email feedback, corrections, request for copies or Index of all reviews
--- to: ------ jamesdetrick@comcast.net ------ “Jim Detrick” -----------
--------------------- --- Thursday, September 30, 2021 ---------------------------
No comments:
Post a Comment