The Sun Close Up

9 Dec 2019

An article in the journal Nature - see https://doi.org/10.1038/s41586-019-1818-7 ... and https://nature.com/article/s4586-019-1811-1 ... see also https://phys.org/news/2019-12-sun-close-up-reveals-atmosphere-highly.html ... concerns the highly energetic particles that are hurled from the Sun. They are, apparently, more varied and active than previously considered by solar scientists. This comes about directly as a result of NASAs Parker Solar Probe which is currently orbiting around the Sun (closer than anything yet to date yet far enough away so that it is not damaged by the solar environment). The intention is to find out how the particles become so fast moving and what is pushing them to accelerate. Streams of particles, mostly made up of protons, can travel faster than the solar wind - like an electrically charged plasma gun.

 

At https://phys.org/news/2019-12-unusual-x-ray-spectral-variability-ngc.html .... which is on the arxiv pre release system - see https://arxiv.org/abs/1911.09622 ... and concerns unusual X-ray spectral visibility in a faraway galaxy.

At https://phys.org/news/2019-12-titan-lakes-spew-nitrogen.html ... new research shows bubbles erupting on frigid hydrocarbon lakes on Saturn's moon Titan, which have been modelled to show they could well be outbursts of nitrogen bubbles - as seen by the Cassini spacecraft.

At https://phys.org/news/2019-12-nasa-parker-solar-probe-sun.html ..... we are back to the Parker Solar Probe which is a feature of the journal Nature in December 4th of 2019, with four articles on findings as solar scientists examine images and data beamed back to Earth after a couple of orbits. The other three are https://nature.com/articles/s41586-019-1813-z ... https://nature.com/articles/s41586-019-1811-1 ... and https://nature.com/articles/s41586-019-1807-x .... and basically, we are being told the Sun is anything but placid and even when it is quiet there is not a lot of quiet in the vicinity of the Sun. How it effects the solar constant model is not being said.

Powerful bursts of light, deluges of particles moving at the speed of light, and massive clouds of magnetised material. All this activity affects the planets of the solar system - including the Earth. It seems that after just three orbits of the Sun the Parker Solar Probe has already changed the minds of scientists. Most of the material thrown out by the Sun is part of the solar wind. This is described as a continual outflow of material that bathes the entire solar system. It is an ionised gas, or plasma, and carries within it the Sun's magnetic field, stretching it out through the solar  system in a giant bubble. One spokesman is quoted as saying, 'the complexity was mind blowing when we first started looking at the data. At the vantage point of just 18 million miles from the Sun (where the probe orbits) the solar wind is much more impulsive and unstable than seen from near Earth. The solar wind is made up of plasma where negatively charged electrons have separated from positively charged ions, creating a sea of free floating particles with individuall electric charge ...'. These free floating particles mean plasma carries electric and magnetic fields and changes in the plasma often makes marks on these fields.

The FIELDS instrument surveyed the state of the solar wind by measuring and analysing the electric and magnetic fields around the spacecraft, and they changed over time. The probe has returned unprecedented data from around the Sun, culminating in new discoveries published in Nature. There is also the SWEAP instrument, short for 'solar wind electrons alpha and protons.' It (and they) are investigating  remnants of structures hurled from the Sun into space and violently changing the organisation of flares and the magnetic field. This will damatically change present theories on how the  corona and the solar wind are being heated. A sort of advance admission the standard view of the Sun requires overhauling. The huge rotational flow of the solar wind has been a surprise. The high speeds we are seeing in the first encounters is nearly ten times larger than predicted in the standard model - or theory.

The solar system is awash with dust - the cosmic crumbs of collisions and comet outbursts. Solar scientists have predicted that dust close to the Sun would be heated up so much it would not exist. Roasted away. Leading to a dust free zone close to the Sun. They have seen for the first time the dust thinning out - and potentially a dust free zone does exist. However, when reading deeper one learns that just a bit of thinning has been detected, and nowhere near enough. As yet a dust free zone does not exist - in spite of the effort to keep this aspect of the standard model alive.

'It is somewhat amazing that we are in solar minimum (a quiet Sun in transition between one 11 year solar period and the next one) and yet the Sun produces many more energetic particle events that we ever thought ...'.