I have been reading up about our Milky Way galaxy and I thought I might share some of the more interesting notes; seeing as how this is basically where we live in the Universe. Our puny little solar system is part of the Milky Way.
The Milky Way is shaped like a flat-ish disk with a diameter of 100,000 to 120,000 light years.
The Milky Way spirals around at about 250 kilometres per second, which is about 560,000 miles per hour.
It takes the Milky Way 200 million years to complete a revolution.
The flat-ish disc of the Milky way is warped, somewhat like a circular piece of paper floating down to the ground might be (see picture), hence the spiral arms 'wobble' up and down as they rotate around the center—causing a sine-wave shape. Each wobble cycle takes 30 million years.
Based on the latest research our Milky Way galaxy contains an estimated 250 billion stars. From what we know this is relatively small for a galaxy. The largest galaxy we can see is Galaxy IC 1101 and it has over 100 trillion stars.
All of the stars you can see at night with the naked eye are contained solely within the Milky Way galaxy.
The Milky Way spawns about seven new stars each Earth year.
As man does not yet have the technology to look at the Milky Way from outside (i.e., from above or below) all pictures that exist depicting the Milky Way are illustrations based on information we have gathered. The following illustration is the latest from the NASA site. It shows the location of our sun (our sun is called Sol) which is located about two thirds of the way along the Orion Spur spiral of the Milky Way.
In the illustration the 0 and 180 degree longitudinal lines are marked with the distance from our Sun (Sol) in light years.
When we look into the night sky with the naked eye 99 percent of what we see is just the Milky Way, and we can only see about 6,000 light years which is really only a small part of the galaxy. In the illustration, the first ring shown outside of Sol indicates how far we can see looking up into a clear night's sky—which is not very far when compared to the size of the Milky Way.
Our Milky Way is part of a galaxy cluster we call the Virgo Super-cluster Local Group. There are some 50 other identified galaxies in the Virgo Super-cluster Local Group.
The Milky Way, like everything else in the Universe, is moving through space at an incredible speed. The most recent calculations indicate that the Virgo Super-cluster Local Group is moving through space at about 600 kilometres per second, or about 2.2 million kilometres per hour.
Those folk that spend their life thinking about this stuff are pretty sure now that the Milky Way is comprised of six spiral arms: the Outer Arm, the Perseus Arm, the Orion Spur Arm (sometimes referred to as the Local Arm because Sol in in this arm), the Sagittarius Arm, the Scutum-Crux or Scutim-Centaurus Arm, and the Norma Arm.
I found it interesting. Hope you do too.