On what day of the year is a line through the center of Earth and sun aligned with the galatic center?

Answer 1

The sun does not align with the galactic center. It misses it by about 5 or 6 degrees. What the sun does do is cross the galactic equator at about that distance from the center, every year on the solstice. This is really a coincidence, as there is no reason the equinoxes or solstices would line up with anything outside of the solar system.

I studied this in detail after all these predictions about that 2012 nonsense. I discovered that this *almost* alignment occurs every year at the same time. But I also discovered how close it is to the 18 hr meridian, or the point of the winter solstice on the ecliptic. That was a surprise.

I assumed you meant when the sun was between us and the galactic center, but Peet is correct, technically, in pointing out that the "line" you asked about would include when the earth is between the sun and the center, six months, or 180 degrees later, (or earlier).

So Raymond, "almost" is a rather fuzzy term, isn't it? You think 5 degrees isn't almost. I think it is. In either case, it isn't aligned.

Stork, it's not 90 degrees. More like 70 or 75, but in either case, that means that the sun will cross the glalctic equator, from our point of view, twice a year.

Answer 2

Actually this will happen twice per year. Once when the Earth is on the side of the sun that faces the galactic center, and once when earth is on the opposite side.

The Galactic Center is in Sagittarius, at 17 hours 45 minutes right ascension. So one of these conjunctions happens during Sagittarius - 270 days after the spring equinox. around December 16th, roughly. The other will happen half a year later, or around June 18th.

Note though that this "conjunction" is not exact. The orbit of the Earth fits on a 2-dimensional plane and it is rare that objects in deep space line up exactly with this, since they are in three dimensions. In this case, December 16th is when we line up with the Right Ascension (the astronomy equivalent of Longitude) but we are off on the Declination (the astronomy equivalent of Lattitude) and we will never be spot on. I think the galactic center it is about 6 or 7 degrees below the ecliptic.

Answer 3

It never is aligned.
It never is almost aligned.

The Galactic centre's direction is at right ascension 17h 45.7m and declination 29 deg. 00' South (in coordinates of 2000)

The Sun's southernmost declination is 23.4393 degrees South, at R.A. 18h 00m at the December solstice (coordinates of current year).

The closest the line can get to the direction of the Galactic centre is 5.5607 degrees. Eleven times the apparent diameter of the Sun.

With precession, the equatorial coordinate system (based on Earth's rotation spin) shifts over a 25,800 year cycle (precession) so that the direction of the Galactic centre passes through the R.A. 18h once per 25,800 years.

When that occurs (around, but not quite in 2012) then the angle is at the minimum of 5.5607 degrees; this can only occur on a December solstice (because that is the day when the Sun's declination is furthest south).

One year before (and after) the year of closest approach, the minimum angle is "bigger" by almost one tenth of an arc-second (smaller than the resolution of the best Earth-based optical telescope).

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Every year, the line joining the centres of Earth and Sun does cross the same Right Ascension as the Galactic centre (and it does so twice if you don't mind the direction of the line).

Every year, the line joining the centres of Earth and Sun does cross the same ecliptic longitude as the Galactic centre (and it does so twice if you don't mind the direction of the line).

Every year, the line joining the centres of Earth and Sun does cross the same Galactic longitude as the Galactic centre (and it does so twice if you don't mind the direction of the line).

Every year, the line joining the centres of Earth and Sun does cross the same Right Ascension as the Galactic centre (and it does so twice if you don't mind the direction of the line).

Every year, the line joining the centres of Earth and Sun does cross the Galactic equator (same Galactic latitude as as the Galactic centre) (and it does so twice if you don't mind the direction of the line).

However, it does not do these at the same time because it never points directly through the centre.

Answer 4

Never . The orbit of the planets about the Sun is tilted almost 90 degrees compared to the swirl of the Milky Way. That's why the band of the Milky Way runs north to south in the night sky, not east to west. The Sun, a planet, and the center of the galaxy can form a triangle, but never a straight line.

Answer 5

Ha----- Bad Astronomy
http://www.bautforum.com/astronomy/66414-galactic-alignment.html

It actually happens every year!

Answer 6

Never.