Hi Lauren,

People have known about the Earth's magnetic field in one form or another for a very long time. Supposedly, people living in ancient China sometime around the 2nd century BC to 1st century AD had already figured out that a small piece of naturally magnetized iron ore (called lodestone) would always point in the same direction if it were suspended so it could move freely. This is how the first compasses were invented. Many centuries later, around 1600 AD, a British scientist named William Gilbert showed that the reason why a compass would always point in the same direction was that the Earth was a giant magnet. However it was not until the early part of the 20th century that we knew the Sun had a magnetic field. An American astronomer named George Ellery Hale was the first to observe the magnetic fields of sunspots using a spectroscope to study something called the Zeeman Effect. In the Zeeman effect, a magnetic field causes a spectral line to split into several components.

People have known about geomagnetic storms since the early 1800s, from observing the effects on compasses and telegraphs during bright auroral displays. A Norwegian scientist named Kristian Birkeland who performed laboratory experiments and conducted scientific polar expeditions was one of the first people to propose that geomagnetic storms were connected to the Sun around 1900. However, his theories were quite controversial at that time and could not be conclusively proven until the early 1960s when measurements from satellites became available.

Kris

Hi Lauren! Magnetic fields were first measurd in sunspots by George Ellery Hale in 1908, after which he also realized the whole Sun was like a giant magnetic with a North pole and South pole.There were clues however that the Sun had a magnetic effect on planets for some time before that. Aurorae had been observed since there were people to observe them, and (at least) by the end of the 19th century people had noticed that Aurorae coincided with magnetic storms measured at the Earth and also that, over time, periods of lots of auroral/geomagnetic activity coincided with periods of lots of sunspots! So, the idea that the Sun was some how magnetically influencing the Earth was born, and Hale's observations helped to prove it. It was only later, when the Voyager spacecraft flew by the outer planets and also the Hubble telescope took pictures of them with aurorae, that it became clear that the Sun's magnetic fields affected other planets, too.

cheers

Sarah

Hi Lauren; I'll just add to the previous great answers that while the Sun's magnetic field really influences the planets, through the interactions of the spewed magnetized plasma with planetary magnetic fields, and various climatological effects, those are fairly small effects compared to things like gravity. The solar magnetic field definitely influences the character of the planets, but for example, the planets would still probably be here if the Solar field was different. (TOO much different, however, and it would definitely play a role on whether planets could form at all, so this is where scientists (and people like you!) get to have fun arguing what is meant by "control" and what's considered "small effects". Cheers, -KD

here's a question

How the solar magnetic field and earth magnetic field can connect together.?