Our galaxy (Milky Way) is one of the spiral galaxies. Our solar system is located in one of the spiral arms. The Milky Way is like a flat disc (diameter: 100000 light-years, thickness: 1000 light-years). The thickness increases at the galactic center.
Our galaxy rotates. The rotation period is 220 million years. The distance between the solar system and the galactic center is 26000 light-years.
There is a super-massive black hole at the center of Milky Way. All stars in the galaxy rotate around the galactic center. Sun’s rotation around the galactic center takes about 225 million years. Sun also moves up and down through the mid-galactic plane. One complete up-and-down cycle takes 64 million years.
Like all galaxies our galaxy moves within space. The speed relative to CMB (Cosmic Background Radiation) is 552 km/second
Our galaxy moves through the interstellar gas cloud like a pie on the face, not like a freesbe
Milky Way’s north is the front facing the interstellar gas
The speed of our galaxy relative to the interstellar gas is 200 km/second
As the galaxy moves against the interstellar gas a shock wave is created. The cosmic radiation due to the shock wave is much greater in the galactic north
The solar system is passing through the mid-galactic-plane and it is on it’s way north. The solar system is getting closer to the radiation region.
The threat of cosmic rays are due to their indirect effects. The danger of cosmic rays is that they create muons when they collide with atmospheric particles. Muons penetrate deep into the oceans
Charged particles caused by cosmic rays increase the cloud cover according to Henrik Svensmark at the Danish National Space Center. New experiments are being carried out at CERN to test Svensmark’s claims. Cloud formation by cosmic rays and the effect on climatology is hotly debated. No firm conclusions have been established yet.
Our galaxy is situated in a local group that includes the Andromeda galaxy, Magellanic Clouds, and about 35 other galaxies. This local group is located within a cluster called Virgo. The members of the Virgo cluster move together in in space.
In our local group, Andromeda galaxy is our largest companion and it is moving towards us. Andromeda and Milky Way will collide in few billions years.