APOD 1.8

For this week's APOD, I chose to write about the picture "It Came From the Sun", uploaded on October 18, 2010.  It is a picture of the Sun, and it was captured by a sun-orbiting satellite called SOHO earlier this year.  There appears to be an orange gas-like looking substance coming off over the edge of the sun.


Solar prominence is what is coming over the edge of the sun in this picture.  Solar prominences are filaments, or thin clouds of solar gas,  held to the sun by its magnetic field.  And, they are on the edge of the sun, appearing brighter than the dark outer space behind them.  A quiescent prominence expels hot gas into the solar system, typically lasting for about a month on average.  On the other hand, eruptions like the one developing in the photograph, might erupt within hours into a CME.  A CME, also known as Coronal Mass Ejection, is a burst of solar wind coming from the solar corona.  Both types of prominences, though, succeed in expelling hot gas into the solar system.  The prominence recorded in the picture was during an early stage of the eruption, and it quickly became the biggest ever recorded.  It was so gigantic, that the whole Earth would be able to fit inside of it.  Prominences look dark when next to the sun because, although they are hot, they are still slightly cooler than the sun's surface.   More large solar prominences are to be expected over the next three years, as the sun evolves toward solar maximum, which is the period of greatest solar activity in the sun's cycle.