B Celestial plane orientation to the galactic core

[AutodiJack]

TL;DR Summary

In relation to the galactic core, is the celestial plane tilted 23.4 toward or away?

Sorry if this is obvious, but I have studied all the images of galactic orientation online, but I need to be sure.

Diagram i made to help illustrate what I mean:

I believe it's towards, using this as a reference: https://www.physicsforums.com/threa...sun-and-solar-system-in-the-milky-way.888643/

But those diagrams don't show the direction of the core, only the poles. Unless I just don't get it.

 

[phinds]

I believe it's a meaningless question since you can look at it as being either way, based on the on the direction you are looking at it from and what side of the galaxy the Earth is on. You have to define the geometry with precise terms, otherwise the answer of "is it angled toward or away" is "yes, it is"

 

[Vanadium 50]

If you flipped your pictures upside down, don't towards and away switch places?

 

[Drakkith]

The answer is in the second picture in your reference. The 'Angle between celestial north and galactic north' is the angle between the Earth's axis and the line pointing from the Sun to the galactic center, and is 62.87 degrees, which means the plane is pointing more towards the core than away.

 

[Drakkith]

I believe it's a meaningless question since you can look at it as being either way, based on the on the direction you are looking at it from and what side of the galaxy the Earth is on. You have to define the geometry with precise terms, otherwise the answer of "is it angled toward or away" is "yes, it is"

I'm not sure what you mean here, phinds. The celestial plane is tilted the same way all day and all year and only changes over very long time scales.

 

[phyzguy]

What is the "celestial plane"? Do you mean the plane of the Earth's equator, the plane of the ecliptic, or something else?

 

[Bandersnatch]

The answer is in the second picture in your reference. The 'Angle between celestial north and galactic north' is the angle between the Earth's axis and the line pointing from the Sun to the galactic center, and is 62.87 degrees, which means the plane is pointing more towards the core than away.

It is the second picture, agreed. But. The angle you're talking about is in a plane roughly parallel to the Sun-Galactic Centre direction. That is, the right ascension of the Galactic North is approx 13h, close to the direction of the autumnal equinox (to the right of the picture). In the picture it represents more the general slant of the plane of the ecliptic than that of the equatorial plane.

Diagram i made to help illustrate what I mean:

As was said, the second is right. However you need to fix the labels. The Earth in that picture revolves around the Sun in the anti-clockwise direction, both by convention and by the depicted orientation w/r to the galaxy. So what follows the winter solstice should be the vernal (spring) equinox, not autumnal. Unless it's meant to represent the direction towards the equinox (but then there would be more to fix elsewhere), and not the time of the year.
Incidentally, the first picture would have Summer when it's labelled Winter, as it's the inclination of the equatorial plane that determines the seasons.

Back to the directions. You can find the equatorial coordinates of the major points of the galactic coordinate system on Wikipedia. The Galactic Centre is towards approx. RA 17h 45m, dec -29 deg. In both cases roughly 5 degrees of arc from the direction towards the Sun during the Winter solstice. That's close enough to assume it's the same direction for our purposes.
So as you look at the second picture, with the Earth at the Winter solstice point, towards the Sun, the declination value tells you how far below ('cause it's negative) the Earth's equatorial plane you'll see the centre of the Galaxy. Since you're looking below, the plane of the equator has to be tilted up - as depicted in the 2nd one.

 

[Drakkith]

It is the second picture, agreed. But. The angle you're talking about is in a plane roughly parallel to the Sun-Galactic Centre direction. That is, the right ascension of the Galactic North is approx 13h, close to the direction of the autumnal equinox (to the right of the picture). In the picture it represents more the general slant of the plane of the ecliptic than that of the equatorial plane.

To be clear, I meant the 2nd picture in the OP's reference, or this PF thread.
Image:

 

[Bandersnatch]

To be clear

Fair enough. I meant OP's drawings when referring to the 2nd picture in my post. The point stands, though.
In the picture from the reference you can see that the two component angles of displacement from the axis of the ecliptic are roughly at 90 degrees. The tilting of the ecliptic w/r to the galactic equatorial plane is pretty much sidewise, so how much the two are inclined does almost nothing to the direction towards the core. You could rotate the entire galactic plane w/r to the ecliptic around the line connecting the nodes (i.e. vary the 60.2 deg angle over full 360 degrees) and you'd get the direction towards the core stay almost the same. That's why the sum of this angle with the axial tilt is a red herring.