I would like to know how one measures the temperature of the interior of the earth if one cannot drill that deep at all, and how do they do that on the sun? I am not yet aware of a device that could withstand the heat from the interior of the sun and one should also be able to drill quite deeply with it?
Answer
The temperature in the center of the earth, and certainly not in the interior of the sun, is not measured. Unfortunately, we can’t (yet?).
How do we know these temperatures? These come from a combination of models and experiments. For example, if one knows at what temperature iron starts to melt under very high pressure, one can make estimates for the temperature of the interior of the earth, if you imagine a model of the earth with liquid iron. If there are indications from the analysis of the movements (rotation and disturbances) of the earth and, for example, also from seismological studies, that your model is correct, you can make estimates in this way. Combining it with other studies, the estimate becomes more accurate and reliable.
The procedure is similar for the sun (and the stars). The astronomers can draw up models for the interior of the sun on the basis of observations (of the outer layers, of the movements on the sun and the stars, …) and general physical and chemical properties. The pressure and temperature in the central part must, for example, be sufficient for nuclear reactions for energy production, and there are many other conditions. Such models – sometimes it is not yet possible to choose exactly which is most probable – then give reliable temperatures for the interior.
Answered by
dr. Jan Cuypers
Astronomy – Astrophysics – Variable Stars Calendars
Avenue Boechout 10 1020 Brussels
http://www.astro.oma.be/
.