Hi Rachel,

Although people have only been as far as the Moon, we've been able to observe the Sun and the stuff that comes off it in many different ways. We have telescopes that look at the Sun in different wavelengths of light (including those not visible with our own eyes). Some of these telescopes are on the ground and some are in space. We also have instruments on spacecraft (and even for a little why experiments on the Moon) that can collect and analyze particles that are coming from the Sun (what kind of particles, how many there are, how much energy they have, etc). When you put these things together you can tell a lot about the Sun even though we've never actually been there.

Just like you can learn a lot about a place on Earth, even though you've never been there, if you look at photographs of the place.

Best,

Christina

Rachel, I'm not a historian, but I've heard about an interesting example of Christina's comment about learning a lot from the light and other particles coming from the Sun. I've read that one of the more common elements on Earth, helium, that makes balloons float up in the air, and can be found in many natural deposits on Earth, was actually first discovered 140 years ago, on the Sun! This happened because a French astronomer was observing light from the Sun's upper atmosphere, during a solar eclipse in 1868. He noticed a special kind of light, with a wavelength that became visible only during the eclipse. It looked almost like light from sodium, but not exactly, so the astronomer guessed it came from a special element that perhaps, he thought, only existed on the Sun, because at that time it was unknown on Earth. So they called this imaginary element helium, which means literally "of the Sun," because the Greek word for Sun is Helios. Later helium was found by geologists, and the same kind of light, with the same wavelength, showed that it was the same element known first from the Sun!