APOD: A February without Sunspots (2019 Mar 06)

Comments and questions about the APOD on the main view screen.
User avatar
Chris Peterson
Abominable Snowman
Posts: 14358
Joined: Wed Jan 31, 2007 11:13 pm
Location: Guffey, Colorado, USA

Re: APOD: A February without Sunspots (2019 Mar 06)

Post by Chris Peterson » Fri Mar 08, 2019 7:29 pm

geoffrey.landis wrote:
Fri Mar 08, 2019 7:23 pm
True. But over the five billion years that the sun has been around, even a very very slight self interaction would equilibrate the concentration.
Maybe... depending on the kind of interaction. If it's gravity alone, the result could be dilution, as well, like the way that globular clusters evaporate. The transfer of orbital angular momentum concentrates some mass, but also scatters some. So any concentration may be paired with an overall mass reduction.
Chris

*****************************************
Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com

BDanielMayfield
Don't bring me down
Posts: 1971
Joined: Thu Aug 02, 2012 11:24 am
AKA: Bruce
Location: East Idaho

Re: APOD: A February without Sunspots (2019 Mar 06)

Post by BDanielMayfield » Sat Mar 09, 2019 12:05 am

geoffrey.landis wrote:
Fri Mar 08, 2019 7:23 pm
True. But over the five billion years that the sun has been around, even a very very slight self interaction would equilibrate the concentration.
What do you mean by this?

I used to wonder about how much of the Sun's mass, the Earth's mass, etc. might be dark matter, but Chris' logical points about momentum put my mind at ease about these questions.

If a significant amount of the mass internal to stars is dark matter it throws off the equations of state re the conditions inside stars and therefore stellar lifetimes. Simply stated, stars can't run on dark matter, so if their cores aren't fully normal matter they couldn't last as long as they are observed to be doing universally.

Bruce
"Happy are the peaceable ... "