3/26/2023 0 Comments Problem with sun coronaBut the measurements show that they coincide with increases in the speed of the solar wind flowing away from the sun. We have no idea what these “switchbacks” really are. For example, the magnetic-field sensors detected large flips in the direction of the magnetic field. The Parker Solar Probe’s first measurements show that variations in the wind’s speed and in the magnetic field are much greater than observed near Earth. The probe even has an imaging instrument onboard that takes photographs of the corona.Īn artistic rendition of the Parker Solar probe as it approaches the Sun. The spacecraft also measures energetic particles, which are ions (atoms that have lost electrons) or electrons that travel much faster than the solar wind. The instruments on the spacecraft directly measure the solar-wind plasma and the electromagnetic fields around the spacecraft. For comparison, the Earth orbits the sun at a distance of 150 million kilometres. Although this number still sounds quite large, it is much closer to the sun than any spacecraft has ever been before. At its closest encounter in 2024, it will be just over six million kilometres away from the sun. Its orbit will bring the spacecraft closer and closer to the sun over the coming years. In 2018, NASA finally launched the Parker Solar Probe to pursue this early dream. But the harsh environment near the sun turned out to be too challenging for spacecraft technologies back then. The first ideas for a mission to uncover the mysteries of the sun date back to the 1950s. Image courtesy: NASA Goddard Where nobody has gone before Parker has made several close approaches, and will continue to weave in and out of the sun's corona over it's remaining 6 years on the job. Luckily, NASA’s Parker Solar Probe has recently achieved a close encounter with the sun and is starting to answer these and many other questions – with its first results just published in a series of papers in Nature (see here, here, hereand here). But how the sun accelerates this wind is another giant mystery. The high temperatures of the corona cause it to expand into space as a continuous outflow of plasma called the solar wind. This discovery has puzzled the field of solar physics ever since. About 80 years ago, scientists found that the temperature of the solar corona is actually much hotter than the surface, at a few million degrees celsius. Like the sun below, the corona consists of plasma – a gas of charged particles. During a solar eclipse, the sun’s outer atmosphere, called the solar corona, can actually be seen as a bright circle, with the moon blocking the rest of the sunlight. In fact, the sun sometimes looks pretty much exactly like a child’s drawing. The yellow colour is determined by the temperature of the photosphere, which is about 5,500☌. This is actually quite accurate, given that the sun is a ball of hot gas and that its surface (called the photosphere) mostly shines in bright yellow light. If you ask a child to paint a picture of the sun, you will most likely get a bright yellow circle on a piece of paper.
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