Hi! It is wonderful to see such enthusiasm! I am going to answer some of your questions, but as separate posts: 1) The electromagnetic radiation of the Sun is formed in its Core, which is so hot and dense that nuclear reactions take place, releasing energy as light (photons) and particles (neutrinos). The light moves out through the Radiation Zone -- but the Sun is still so dense that the photon bounces around so that it takes millions of years to travel to the surface of the Sun, or photosphere. The photosphere is the layer of the Sun's atmosphere at which the density reaches a point where the light can travel straight outwards -- thus it is what we see as the disk of the Sun! Here is a useful web site -- click on the image and it will show you more information! http://www.windows2univer...ar_interior_new.html cheers Sarah

Hi again: 2) Solar telescopes are getting bigger and better, and spatial resolution has got to the point that we can really zoom in on the Sun's surface and atmosphere. Just take a look at this image: http://www.solarphysics.kva.se/ Some of this is because of very large telescopes, and some because of "adaptive optics" which compensate for the difficulties raised by the Earth's atmosphere above the ground-based telescopes, see for example http://www.sciencedaily.c.../10/051010094317.htm Space telescopes get some nice images (and movies!) too -- in general, the really big telescopes don't go up in space (too expensive!) but the atmosphere is not a problem, and also wavelengths of light such as extreme ultraviolet and soft Xray, which are not accessible from the ground because of the Earth's atmosphere, can be viewed from there. The results are pretty amazing, see http://sdo.gsfc.nasa.gov/...hots.php?v=item&id=1 The BIG solar telescope of the future will be the Advanced Technology Space Telescope, or ATST, which will be built in Hawaii and is expected to be ready for viewing in 2017. It will have a 4 meter main mirror, and be the largest solar telescope in the world. As such, it will have the best spatial resolution ever, showing features smaller than 70 km wide at the solar surface.

Hi again! 3) Solar eruptions are perhaps my favorite things to observe. They show up as bright flashes of light -- or solar flares -- but also as masses of solar material being flung out from the Sun. What I think I like the best is the swirling and twisting motions that go along with these eruptions. See http://sohowww.nascom.nas...k/Twisting_prom.mov. This twisting makes for great movies, but also helps us understand why the eruption is happening. The part of the Sun we are seeing in these eruptions is the outer atmosphere, or Corona. The corona is full of magnetic fields, and when these fields are twisted up they are more energetic. Think of a rubber band getting twisted and twisted, until finally it snaps! That is what is like when magnetic energy in the corona reaches a point that an eruption occurs, and when it does, the twisting and untwisting fields become evident in the eruption.

Hi! 4) While the explosions are the most fun to watch, there are certainly lots of other things happening on the Sun. As we zoom in with better spatial resolution, and increase our temporal resolution so we start to see in "near-real time", we see that the corona is constantly on the move. See this movie from the Hinode satellite: http://solarb.msfc.nasa.gov/movies/okamoto.mpg. The little black spot is a sunspot, and the edge, or "limb" of the Sun can be seen in the middle of the image. The bright structures that look like grass being blown back and forth are called "spicules", and the large, horizonatal flows above are part of a solar "prominence". These prominences are relatively cold and heavy structures, that are suspended in teh corona by the support of magnetic fields. Prominences are often observed to erupt (the last post had a movie of one!) when these magnetic fields reach a critically energized state.

5) This is an interesting question! Yes, there are. Other stars can have flares, and eruptions, just like the Sun. In stars that are not just like the Sun, for example very fast rotaters, the flares can be even more energetic. See http://www.nasa.gov/missi...s/monster_flare.html for an example. This is a nice example of how observations of the Sun complement those from other stars. With the Sun, we see the eruptions from an amazing close vantage point: more than that, when the eruption moves past us on the Earth we can measure it "in situ". We get a unique perspective, and for example can figure out how magnetic fields power the eruptions. By observing other stars, we can ask "what if?" What if the Sun was bigger/smaller older/younger faster-rotating/slower-rotating than it is? How would that change its dynamics?

7) Solar explosions pretty much only affect our solar system. However, our most distant spacecraft, Voyager I and II sometimes observe eruptions (coronal mass ejections, or CMEs) as they move past the farthest reaches of the solar system. See http://www.universetoday....outer-solar-system/.

8) Solar eruptions definitely may affect the Earth -- but in terms of being dangerous, it is only the last century or so that this has become a problem. Before that, even the biggest solar eruptions didn't do much except make beautiful aurorae in the skies as particles energized by the eruptions slipped down the magnetic fields at the Earth's poles. However, we are getting more and more technologically dependent, and the consequence is that "Space Weather" is a real concern! For one thing, along with the aurora there can be electric ground currents generated at high latitudes that may shut down power stations. Satellites in space are even more exposed to "solar storms", and may shut down or fail completely. Radio communication can also be disrupted, and finally there are radiation hazards to pilots and other airplane personnel flying polar routes. Luckily, most of the radiation hazards of solar eruptions are minimal because the Earth's magnetic field acts as a protective cocoon. However, if astronauts fly to Mars they will leave this cocoon, and it becomes a serious issue. See http://www.windows2univer...her/basic_facts.html for more information.