Our Sun

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

Checking in on Jupiter: the belt is coming back

Posted by Emily Lakdawalla on 2011/03/25 03:46 CDT

Since it's been several months since I last took a look at Jupiter, I thought it was time to see what's up with the South Equatorial Belt.

A solar eclipse - as viewed from the Moon

Posted by Emily Lakdawalla on 2012/05/28 11:19 CDT | 3 comments

A solar eclipse isn't just a spiffy sight to Earthlings; it looks pretty cool to lunar dwellers as well.

"False-tonal recording?" The sounds of a coronal mass ejection

Posted by Emily Lakdawalla on 2012/03/15 12:26 CDT

A new "sonification" of the recent solar storm by Robert Alexander (a University of Michigan graduate student), employing data from the MESSENGER and SOHO spacecraft.