Booming with old and young stars, M101 has some huge and extremely bright H II regions. In this image these can be seen as the tiny pockets of fiery red and these areas are mainly comprised of enormous clouds of hydrogen gas and star forming regions we often refer to as nebulae.
The fact that it is 21 million light-years away, means that the light we're seeing in this image left the Pinwheel Galaxy about 21 million years ago - many millions of years before humans ever walked the Earth.
This image was taken by astrophotographer Terry Hancock. You can view more images from Terry Hancock on his Flickr page as well as his Facebook page Down Under Observatory and his website www.downunderobservatory.com.