Polaris

Comments and questions about the APOD on the main view screen.
moodman
Asternaut
Posts: 2
Joined: Mon Jul 18, 2005 3:47 pm

Polaris

Post by moodman » Mon Jul 18, 2005 3:52 pm

Hi All,

I am a newly registered member here, and have been viewing APOD for almost 8 years. A recent picture piqued my interest.

The picture is the "Star Trails Over Vienna" picture of July 14.

I had always thought that Polaris was THE center of our star's apparent revolution, yet it can be seen that there is a dark space at the actual center near Polaris, meaning that Polaris revolves too!

Now, my question is: "What is at the TRUE center of the revolution?"
Has Hubble ever photographed this true "center"? If you have a picture of this true center, can you link me to it? I think others might have the same question.

Thanks in advance.

Odegard
Ensign
Posts: 16
Joined: Tue Jun 14, 2005 11:10 pm

Post by Odegard » Mon Jul 18, 2005 5:03 pm

Stars move about in the Milkyway and it's only chance that there is a star close to earths rotation axis today.

moodman
Asternaut
Posts: 2
Joined: Mon Jul 18, 2005 3:47 pm

Post by moodman » Mon Jul 18, 2005 5:30 pm

I understand, but I am referring to the"dark" space which shows up in the very center of the apparent Polaris' orbit. I was thinking that maybe the Hubble has done a deep field photo of this area, and am wondering what such a picture would reveal?

Odegard
Ensign
Posts: 16
Joined: Tue Jun 14, 2005 11:10 pm

Post by Odegard » Mon Jul 18, 2005 5:49 pm

The Milky Way is a relatively thin disk of stars. Earths rotation axis points outwards from this disk. There might be stars located behind Polaris, or more aligned to the rotation axis, but I don't know of any such stars.

However, you can be certain of finding a galaxy if you look hard enough. Take a look here: Hubble's Deepest View of the Universe Unveils Bewildering Galaxies across Billions of Years

What this means is that where ever you look, if you look hard enough, you'll eventually see a galaxy.
Maintainer of the Norwegian mirror

William Roeder
Ensign
Posts: 59
Joined: Thu Jun 16, 2005 3:46 pm

Post by William Roeder » Mon Jul 18, 2005 5:55 pm

The motion of the stars around the Milkyway is a minor dynamic. It will take 100's of thousands of years before nearby stars (like Polaris) change their position noticably.

The precession of the Earth's axis takes only 26,000 years.

See Why is Polaris the North Star?