The Sun's core is the hottest part of the Sun.
But our star's temperature doesn't behave as you might expect.
The core is roughly 27 million degrees Fahrenheit and 10 times more dense than gold.
As you move outward, the layers of the Sun become cooler and less dense.
Something unusual, however, occurs when you reach the outermost layer.
While the surface is around 10,000 degrees Fahrenheit, the corona, the Sun's outer atmosphere, is several hundred times hotter.
That's the opposite of what happens with a fire, when it gets cooler the farther away you get.
Scientists call this the coronal heating problem and evidence for this was first uncovered during an eclipse in the 1800s.
The corona is usually hard to see, it's too dim to be seen next to the Sun's bright body.
But it can be seen with the naked eye when the moon blocks the sun during a total solar eclipse.
