Talk:Heliopause (astronomy)

Supersonic and subsonic are terrible terms when applied to intersteller radiation. We need better ones.

The 'heliopause' page talks about the distance to the heliopause being closer in the direction of the Sun's orbit around the galaxy. I would have thought that the intersteller medium would be travelling in the same orbit as the Sun. Wouldn't the heliopause be closer in the direction of the Sun's motion through the intersteller medium, which is NOT necessarily the same direction as the Sun's orbit?

WRT supersonic and subsonic: what exactly is the speed of sound in a medium in which there is no sound?!?


 * Zero, of course, but those terms provide a useful point of reference in explaining such high speeds to the non-scientific. There are probably better terms, though I can't think of any right now. -- Jim Redmond 17:42, 6 Nov 2003 (UTC)


 * I would have expected subsonic, in this context, to refer to the speed of sound in the solar wind (around 10 km/s, apparently). I'm pretty sure it's not related to the speed of sound in air.  Sorry if that's what you meant and I just didn't get it. -- Prumpf 01:15, 10 Nov 2003 (UTC)

If it wouldn't be the speed of sound in the solar wind, the definition of the "termination shock" would be completely arbitrary.


 * "what exactly is the speed of sound in a medium in which there is no sound?!?"
 * Afaict there is sound in any medium its just denser mediums transmit it better than less dense ones and the solar wind and intersteller medium are very low density so sound transmission is extremely weak.

could someone knowledgeable check this out?
I made one correction, but what is meant by the particle's being "highly energised by their negative acceleration"? If the particles are slowing down, they're losing energy, no?. Matt 04:48, 26 February 2006 (UTC)

Differentiating shock and pause
"The distance to the heliopause is 76 AU, as detected by Voyager 2." Voyager 2 has now reached the heliopause itself or the termination shock before it? I have been reading the latter (i.e., the solar wind has not been actually stopped where the crafts are now). Does anyone know the space between the shock and the pause? Is this line strictly accurate? Marskell 13:01, 25 May 2006 (UTC)

I'm pretty sure that this is the distance to the termination shock. NHammen 22:25, 29 June 2006 (UTC)
 * This article no longer mentions how far away from the sun the Heliopause is. Can we get an update? Firsfron of Ronchester  03:46, 12 April 2007 (UTC)