Thanks Chuck (and welcome back to the list). What you wrote makes sense. If our sun's heliosphere was visible to outside observers in some solar system far far away, then obviously almost all the stars we see in the night-time sky would have observable heliospheres. If that were the case, then objects like the Bubble Nebula would be something of a ho-hum sort of thing not worthy of Tyler Allred's, David Rankin's or Joe Bauman's time and effort. --- On Tue, 1/11/11, Chuck Hards <chuck.hards@gmail.com> wrote: From: Chuck Hards <chuck.hards@gmail.com> Subject: Re: [Utah-astronomy] So Long, Solar System To: "Utah Astronomy" <utah-astronomy@mailman.xmission.com> Date: Tuesday, January 11, 2011, 10:23 AM On 12/27/10, M Wilson <astro_outwest@yahoo.com> wrote:
Okay Joe (or anybody), I have a question.
If someone on a distant planet took an astro-photo type picture of our little star, would the heliosphere show up as something similar to the Bubble Nebula? Or is the gas and partricles just to tenuous for it to be detected.
You know, that's an excellent question. My 2 cents: The heliospheres of dwarf-type stars (such as our sun) are tiny, mere light-hours in diameter. Planetary nebulae are huge in comparison, light-years across, and with higher densities. When referring to solar wind behaviors at extreme distances, we are actually talking about pressure regions and magnetic flux lines, rather than a visible, obviously material structure.
From Wiki: "The point where the solar wind slows down is the termination shock; the point where the interstellar medium and solar wind pressures balance is called the heliopause; the point where the interstellar medium, traveling in the opposite direction, slows down as it collides with the heliosphere is the bow shock."
Here's the entire Wiki entry: http://en.wikipedia.org/wiki/Heliosphere _______________________________________________ Utah-Astronomy mailing list Utah-Astronomy@mailman.xmission.com http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy Visit the Photo Gallery: http://www.slas.us/gallery2/main.php Visit the Wiki: http://www.utahastronomy.com