Science Forums 2

[Turtle]

Originally Posted by Essay

Parallel? Did you mean perpendicular?

Uhm...erhm...I don't think so? I had it in my mind that the axes through the galactic plane & solar plane were parallel.
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Originally Posted by Esssay

Cool Pic!
from: IRAS View Of The Milky Way Galaxy
"The hazy, horizontal S-shaped feature that crosses the image is faint heat emitted by dust in the plane of the solar system."

Yes, that blue line is at ~60 degrees! Not quite the 90 degrees I thought it was, but still far from parallel.
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Shall we say, "not aligned" as we thought? Picture's worth a thousand words at any angle.

Originally Posted by E Say

PHY 445/515: Coordinate Systems
"The ecliptic coordinate system is based on the apparent Solar orbit, and is the natural system for Solar System studies.... The inclination of the ecliptic with respect to the celestial equator is 23 degrees."

Shouldn't that 23 degrees be added onto the 62 degrees (Earth's angle) to get the angle of the solar system to the galactic plane?

But it looks like 60ish degrees.
Maybe that's a mistake, and they should be saying "The galactic equator is inclined to the celestial ecliptic equator by 62.6 degrees."

...or does it just "look" that (62 degrees) way because it's photographed from earth?
...and the galactic equator would be inclined ~86 (62.6+23.3) degrees to the ecliptic equator?
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I puzzled over this awhile when reading the link. I think the explanation is in this part (boldening mine):

Originally Posted by Stony Brook

Ecliptic Coordinates
The ecliptic coordinate system is based on the apparent Solar orbit, and is the natural system for Solar System studies. The equator (the ecliptic) is the plane of the terrestrial orbit, projected onto the celestial sphere. The poles are projections of the Earth's orbital poles. Coordinates , are measured in degrees. The inclination of the ecliptic with respect to the celestial equator is

23o26'21".448 - 46".82T - 0".0006T2 + 0".0018T3,
where T in the number of Julian Centuries from 2000AD. The origin is the same as that of the celestial system. The north ecliptic pole is located at 18h +66o33' in celestial coordinates. Conversion from ecliptic to celestial coordinates involves only a rotation of the sphere. ...

Originally Posted by Eee Say

Any info. on direction of travel (Southern Hemisphere forward?)?
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Great links: Thanks,

~

Nothing that I have seen yet on who leads, N or S.

My pleasure; thanks for interesting questions. I think we can worry this bone a bit more before we bury it, eh?