Clear moonless nights in August are the best nights to see for yourself how our Solar System is oriented within our Milky Way Galaxy. On many summer evenings every year I look above our southern horizon and stand in awe. The quote that always comes to mind is one credited to Einstein, “The most incomprehensible thing about the universe is that it is comprehensible.”

I can still recall how completely surprised I was when I first became aware that I could see this orientation in our night sky. I had barely recovered from that surprise when I was hit with a second. Our Solar System lies within the main disk of our Milky Way galaxy but is not in a parallel orientation to the main disk of stars. The plane of our Solar System, the Ecliptic, intersects the plane of the main disk of our home galaxy at about a 60-degree angle. I realized that my intuition had led me to think that the plane of our Solar System would lie within and be “parallel” to the plane of the Milky Way disk.

It is truly incredible that we can observe the orientation of our Solar System in the Milky Way Galaxy in person, in real time, and interpret it correctly. Who was the first person to realize and verbalize this relationship correctly, I wonder? What a feeling that must have been! The above along with knowing where to look to see the North Galactic Pole and the North Ecliptic Pole helps me in my age old quest of – where am I and where am I going?

We see the plane or main disk of our galaxy running pretty much northeast (overhead) to southwest – so where must the North Galactic Pole be? It is 90 degrees or perpendicular to the main disk and so it is to the northwest.

We see the Ecliptic (the arc the planets, Moon, and Sun appear to travel) running across our southern sky at this time of night and year. Where must the North Ecliptic Pole be? It is 90 degrees or perpendicular to the Ecliptic Plane and so it must be pretty much to the north. Note the angular distance between the North Galactic Pole and the North Ecliptic Pole is about 60 degrees – that matches the angular intersection between the two planes – cool! 3-D geometry in the night sky is fun!

Bowing to the adage, “A picture is worth a thousand words”, I hope the graphics help in finding your own orientation in space and time.

Next week we will explore Aquila, the Great Eagle that flies overhead along the Milky Way and toward the center of our home galaxy.

Clear skies.