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Ever since humans have inhabited earth, we have known that the sun is round. However, turns out that it is even rounder and flatter than had been previously believed. What's even more amazing is that its shape never alters, a fact that is surprising given that it is a gaseous ball of fire. How is that possible? That, is a mystery that scientists are now planning to solve!
The reason scientists are a little miffed by this seemingly faultless perfection, is because as the sun goes through its 11-year long solar cycle, the number of sunspots on its surface rise and fall dramatically. Scientists had always assumed that its shape changed along with this cycle. That's because they believed that the tremendous magnetic activity that accompanies the solar cycle cause the gases in the sun's interior and atmosphere to constantly shift around. Give that the sun does not have a solid surface, it should logically result in altering the sun's spherical shape.
And the theory had been further reinforced by the fact that measurements of the sun taken over the last 50 years, had never been consistent.
However, as the scientists had long suspected, the measurements had not been very accurate. Now thanks to NASA's Advanced Solar Dynamics Observatory satellite, astronomers have been able to obtain more consistent data, because the laboratory is in space and therefore, not distorted by the earth's atmosphere.
For this most recent study the results of which were published in Science Express on August 16th, 2012, the scientists used measurements obtained by the satellite from 2010 to 2012, a two year time span when the sun's activity ranged from minimum to maximum. What they discovered was that irrespective of the level of activity, the sun remained perfectly round - So perfectly spherical that its equatorial diameter (where it is at its widest horizontally) measures almost the same as diameter between its polar ends.
The team of scientists led by University of Hawaii physicist and solar researcher, Jeffrey Kuhn, say that this finding probably means that subsurface forces, like solar magnetism or turbulence are a more powerful influence on the sun than they had previously thought - A theory they plan to investigate right away.
Resources: csmonitor.com, huffingtonpost.com