How can astronomers study what happens inside the Sun?

We have instruments we can design to measure specific properties of the Sun such as its temperature, the motion of its gases near the surface, and the kinds of particles that it emits into space including light. We have also learned a thing or two about the detailed laws of nature and the way matter behaves under the influence of gravity and the other 3 fundamental forces in nature. We construct mathematical 'models' of the Sun and its interior, and find the model, based on our understanding of physics, which matches the data we have the best. We then ask these models to predict what the interior of the Sun looks like, and it is these mathematical descriptions that we translate into words to answer questions about the interior of the Sun. Also, we look for how the different predictions for the interior of the Sun affect the data we have, and we then build new instruments to measure the slight differences that these different predictions make.

The most powerful method we now have is to measure what are called 'solar oscillations'. The Sun rings like a bell, and depending on the way that the speeds of the surface layers change their speeds in time and across the Sun's surface, we can probe the deep interior of the Sun much the way we use earthquakes on the Earth to probe the interior of the Earth. Solar oscillation studies have independently confirmed what current models of the Sun's interior have been saying for decades, namely, that the outer 1/2 of the Sun is a region of gas convection. By studying the data in more detail, astronomers hope to study how the interior convection pattern changes during the sunspot cycle and in other ways, so that we can get a clearer 'picture' of what the Sun looks like inside.

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All answers are provided by Dr. Sten Odenwald (Raytheon STX) for the
NASA IMAGE/POETRY Education and Public Outreach program.