![]() ![]() The most recent estimates have suggested a likely distance of around 20 parsecs, or 65 lightyears. Most measurements are based on statistical studies of the distribution of stars, clusters, gas or dust around the Sun, and estimates have ranged from only 6 parsecs (1 parsec is about 3.26 lightyears) to as much as 42 parsecs. Since then, a variety of techniques have been used to try and estimate just how far above the galactic plane the Sun actually sits. Observations of the distribution of neutral hydrogen gas in the 1960s indicated that our Sun sits somewhere above the mid-plane of our galaxy, the Milky Way. The Sun is currently thought to be about 65 lightyears (or 20 parsecs) above the galactic plane The oscillations have wavelengths ranging from thousands to hundreds of thousands of kilometres. We see three types of waves in the motion of the Sun’s surface: acoustic, gravity and surface gravity waves. ![]() The temperature, composition and other properties of the solar interior strongly influence the behaviour of these waves.Ĭombining such observations with theories about star structure allows astronomers to produce models of the Sun’s internal composition. The waves within the Sun can be best described as a continuum and many sources produce a constant acoustic ring.Īt the solar surface, these waves produce tiny up and down motions in the gases, which can be seen as Doppler shifts in high resolution spectra. Observing the oscillations reveals the properties of the different layers. These waves cause vertical motions at the Sun’s surface, the photosphere. Like terrestrial seismologists, helioseismologists use oscillations to probe the interior of a body: seismic waves generated by earthquakes in the case of the Earth pressure waves within the convective zone in the case of the Sun. Much of our knowledge of the solar interior derives from helioseismology. In order to understand the structure of the Sun, astronomers use a mixture of observation, theories and computer modelling to come up with a picture that best describes the characteristics that have been recorded. Geological Survey, Mineral Commodity Summaries, February 2019 pp 76-77.Helioseismologists measure the speed at which acoustic waves travel through the Sun’s interior. We’re Running Out of Helium, and Two Geologists Might Have a Fix. Helium: An Irreplaceable Resource and Why We Must Conserve It, 2019. American Physical Society Policy Reports Page. Research Community’s Liquid Helium Crisis. Royal Society of Chemistry Periodic Table Page. Sustainable Development Goal #3: Good Health
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