Astronomy
The Zeeman Effect and Measuring Magnetic Fields in the Sun
Quick fact
By observing the Sun through a spectroscope, astronomers can measure magnetic field strengths in sunspots that are thousands of times stronger than Earth's magnetic field, simply by looking at the tiny splitting of specific spectral lines.
Why this is interesting
You know how a strong magnet can bend the light from a distant star? It turns out, the Sun's own magnetic fields do exactly that, and we can measure them by the way they twist the rainbow colors of sunlight.