Most people who can pick out at least two constellations in the night sky can point out the Big Dipper. As it turns out, the Big Dipper is not a constellation. It’s an asterism within the constellation Ursa Major (Big Bear). An asterism is only a part of a constellation; it’s like a picture within a picture.
The Big Dipper is probably the most beneficial star pattern to know. The reason? The two end stars of the bowl point toward the North Star (Polaris). That star has been giving guidance at night for generations. It’s the only bright star that doesn’t seem to move out of place all night, or even all year. The final twelve missionaries that escaped captivity in Haiti in December of 2021 had a testimony of being helped by God to reach freedom. One of the ways He sent His help was by the reliable positioning of these stars, giving them guidance in those early morning hours.
The two end stars of the dipper bowl are named Dubhe and Merak. Merak is at the bottom of the bowl and is about 80 light years away from us. Dubhe is the top star of the bowl that points toward Polaris and is over 120 light years away. That’s about 235 trillion miles farther away. Most constellations show the patterns they have because of being in a specific alignment instead of all being in the same area of space.
The Big Dipper is as persistent as it is precise in showing the way to the North Star. For most people in North America, it never sets. Instead, it spins in a silent circle around the North Star once per day. In March after sunset, the Big Dipper looks like it’s standing on the end of its handle.
When we look up into the night sky, we are literally seeing an out-of-this-world view. Depending on where you look, it can be hard to see out of our home galaxy. We are right in the disk of the enormous Milky Way Galaxy, packed with over 100 billion stars that are spread through huge gas and dust clouds. When we look toward the Big Dipper, we’re looking up out of this crowded disk of our galaxy for an out-of-this-galaxy view.
Huge galaxies are visible around the Big Dipper area. Just below the handle end star, Alkaid, sits the well-known Whirlpool Galaxy. Just above Alkaid is the large Pinwheel Galaxy. They are both over 20 million light years away. That means it would take 20 million years to get there if you’d blast off toward them at 186,000 miles per second! On the other end of the Big Dipper is a pair of galaxies named M81 and M82. They are probably the easiest-to-see pairing of galaxies in a telescope.
There is a pairing of stars in the Big Dipper itself too. The bright star Mizar and dimmer star Alcor sit at the crook of the handle. People in various ancient cultures used this double star as an eyesight test instead of spending money at the optometrist to accomplish the same thing. In a telescope, you can see a third star in the group, Mizar B.
Professional observatories have found that there are actually five stars in the group. The stars we see in the night sky usually appear a single point of light, but, in reality, close to half are multiple star systems close enough to each other to join their light into one spot.
So that star you see is not always a single star, and the Big Dipper is not a categorical constellation. Therefore, things aren’t always as they appear, much to our complete consternation.