All the planets, moons, and smaller things in the solar system are just dust, compared to the star that they orbit; the Sun contains 99.9% of the mass of the solar system. We think of it as our source of light, but it doesn't just emit photons. The solar wind blasts fast-moving electrons, protons, and highly ionized atoms in all directions, a constant stream punctuated by ferocious coronal mass ejections. The solar wind carries with it a magnetic field wound into a tight spiral by the Sun's rotation.
The solar wind pushes outward against the interstellar medium, penning the solar system inside a bubble called the "heliosphere" that's at least 200 AU across. The twin Voyager spacecraft are now probing the heliosphere's edges. Closer to home, a fleet of spacecraft monitors the space weather generated by the Sun, warning us of its effects on Earth, from the benevolent (aurorae) to the potentially disastrous (irradiation of astronauts and damage to communications satellites and power grids). Currently operating solar space observatories include ACE, GGS, WIND, Hinode, PICARD, RHESSI, SOHO, SDO, Solar Monitoring Observatory, and STEREO.
Latest Blog Entries about the Sun, Heliosphere, and Space Weather
Posted by Bruce Betts on 2014/05/01 05:31 CDT
Explore the physical characteristics and inner workings of the Sun and then learn all about Stars and Stellar Evolution in this video of class 12 of Bruce Betts' Introduction to Planetary Science and Astronomy class.
Posted by Emily Lakdawalla on 2011/12/06 02:39 CST
Emily reports from the Fall 2011 American Geophyisical Union meeting about advancements in space weather prediction.
In 2016, The Planetary Society’s LightSail program will take the technology a step further.