Big Dipper and Little Dipper

Introduction

If you step outside on a clear night, you'll likely see an arrangement of stars called the Big Dipper and the Little Dipper. These famous star groupings have been part of human culture for thousands of years, helping navigators and inspiring stargazers worldwide.

In this article, we'll examine these two dippers in more detail: what they are, how we can spot them in the night sky, how they got their names, what the difference between the two is, and many more.

Asterisms and Constellations

Before we start exploring these star arrangements, it is essential to understand the difference between constellations and asterisms. Despite popular belief, both dippers are asterisms.

Asterisms and constellations are basic ideas in astronomy, but they show different aspects of star observation.

Constellations are patterns of stars in the sky that astronomers have officially named and recognized. Historically, people have associated these patterns, which often form recognizable shapes or figures, with mythological characters, animals, or objects. They help astronomers, sailors, and navigators find specific areas in the sky.

Some famous constellations include Orion, Ursa Major (which includes the Big Dipper), and Cassiopeia. In modern astronomy, there are 88 recognized constellations.

Asterisms are informal groups of stars inside one or multiple constellations. Unlike constellations, asterisms are not officially recognized by astronomical organizations but are instead popularly recognized by stargazers. They serve as easily recognizable landmarks in the sky, aiding amateur astronomers in locating specific stars or constellations.

The Big Dipper, Little Dipper, and the Summer Triangle are examples of well-known asterisms. The Big Dipper is part of the larger Ursa Major constellation, and the Little Dipper - is part of Ursa Minor. Meanwhile, the Summer Triangle comprises stars from the constellations Cygnus, Lyra, and Aquila.

The Big Dipper

The Big Dipper is one of the most recognizable asterisms in the night sky. Seven bright stars form it, tracing out the shape of a ladle or a dipper. It is part of the larger Ursa Major constellation or the Great Bear.

The Big Dipper is visible throughout much of the Northern Hemisphere. Different cultures have observed and referenced it throughout history.

How Can I Find the Big Dipper

Finding the Big Dipper in the night sky is relatively easy, as it is one of the most recognizable star patterns.

To find the Big Dipper in the sky, start by locating the northern part of the sky. In the northern hemisphere, it's typically visible year-round. Look for a large ladle-shaped pattern of seven bright stars. These stars form the outline of the Big Dipper, with the bowl of the spoon resembling a rectangle and the handle extending from it.

People often call the two stars at the end of the spoon's bowl the "pointer stars" because they point toward the North Star, Polaris.

The Big Dipper Moves Around

Because of the Earth's rotation, the Big Dipper appears to move around Polaris, also known as the North Star. As the Earth spins on its axis, stars in the night sky circle around the celestial pole near Polaris in the northern hemisphere. Since the Big Dipper is close to Polaris, it looks like it moves around the star throughout the night.

However, it's important to remember that the stars stay in fixed positions relative to each other. The movement of stars we see is due to Earth's rotation.

How Did the Dippers Get Their Names

The Big Dipper's and Little Dipper's name comes from its resemblance to a ladle or dipper. The name "dipper" comes from their bowl-like shape, while "big" or "little" distinguishes them from each other. These names come from ancient cultures. Back then, people often linked celestial objects with familiar shapes and items from their environment.

As for the whole constellations, they have been depicted as various objects throughout history, including a bear, a wagon, and a spoon. While the tradition of associating them with a bear is Indo-European, appearing in Greek mythology and Vedic India, the name "bear" also has similarities in Siberian and North American traditions.

The Big Dipper Stars

Of course, as the Big Dipper is only an asterism and not the whole constellation, it does not consist of that many stars. Nonetheless, here are the seven beauties that make up the Big Dippers asterism:

1. Dubhe: One of the brightest stars in the Big Dipper and serves as the pointer star to Polaris, the North Star. It is an orange giant star approximately 123 light-years away from Earth.
2. Merak: Another bright star in the Big Dipper, situated next to Dubhe. It has a slightly bluish hue and is about 79 light-years from Earth.
3. Phecda: The third star from the end of the handle of the Big Dipper. It is a white giant star 83 light-years away from Earth.
4. Megrez: The faintest star in the Big Dipper's bowl and serves as the connecting point between the handle and the bowl of the Dipper.
5. Alioth: The brightest star in the Big Dipper's handle and the third brightest overall in the constellation. It is a blue-white star approximately 81 light-years away from Earth.
6. Mizar: One of the most famous stars in the Big Dipper. A binary star system with Alcor located about 78 light-years away from Earth.
7. Alkaid: The last star in the handle of the Big Dipper. A hot blue-white main-sequence star approximately 101 light-years from Earth.

The Little Dipper

The Little Dipper, part of the constellation Ursa Minor, lies in the northern celestial hemisphere. It is smaller and less prominent than its counterpart, the Big Dipper. It was also spotted in Ptolemy's time and is considered one of the oldest constellations known to the ancient Greeks.

Ursa Minor is famous for containing the bright star Polaris. Polaris has been important for navigation throughout history because it marks the direction of the North Pole.

Like the Big Dipper, it resembles a spoon or a scoop, with Polaris at the end of its handle.

How Can I Find the Little Dipper

To find the Little Dipper in the sky, you first need to locate the North Star. The end of the handle of the Little Dipper. That is the brightest star in the constellation and serves as a guide.

If you can't find the North Star at first, you can use the Big Dipper as a helpful guide to find this northern coordinator. The two outer stars in the bowl of the Big Dipper point directly to Polaris. Imagine a line connecting these two stars and extending it about five times the distance between them. This line will lead you to Polaris; from there, you can trace the rest of the stars in the Little Dipper.

The Little Dipper Stars

1. Polaris: The brightest star in Ursa Minor. It's a reliable navigation guide because it stays almost still in the sky while other stars move around it. Polaris is a yellow supergiant star located approximately 434 light-years away from Earth.
2. Kochab: Another prominent star in the Little Dipper. It is an orange giant star approximately 130 light-years away from Earth.
3. Pherkad: A blue-white giant star located approximately 487 light-years away from Earth. It is part of a binary star system, meaning it has a companion star.
4. Yildun: A star system consisting of two white stars. It is approximately 180 light-years away from Earth.
5. Epsilon Ursae Minoris: A star system consisting of two yellow stars. It is 347 light-years away from Earth.
6. Zeta Ursae Minoris: A star system consisting of two white stars. It is approximately 380 light-years away from Earth.
7. Eta Ursae Minoris: Star system consisting of two yellow stars. They are approximately 97 light-years away from Earth.

Differences Between the Big Dipper and the Little Dipper

Size and Brightness

The Big Dipper is larger and brighter than the Little Dipper. Its stars are more widely spaced, easier to distinguish, and all approximately the same brightness. In contrast, the Little Dipper is smaller and has fainter stars with different brightness levels. You need darker skies and careful observation to see its shape clearly.

Part of Something Bigger

The Big Dipper is just a smaller part of the much larger Ursa Major Constellation. The Little Dipper asterism is part of the constellation known as Ursa Minor. However, the asterism and the constellation pattern are the exact same. It is somewhat rare for both of them to have the same pattern.

Position in the Sky

The Big Dipper is farther from the celestial pole than the Little Dipper. This makes the Little Dipper harder to spot, especially with light pollution or obstructed views.

Conclusion

In conclusion, our detailed exploration of the two Dippers has provided a comprehensive understanding of their characteristics:

1. An asterism is an informal grouping of stars within or across constellations, often recognized by stargazers. In contrast, a constellation is a formally recognized pattern of stars by the IAU with historical, cultural, and scientific significance in astronomy.
2. The Big Dipper is one of the most recognizable asterisms in the night sky. It is formed by seven bright stars that seem to trace out the shape of a ladle or a dipper. The Big Dipper is part of the larger Ursa Major constellation or the Great Bear. 
3. The Little Dipper, part of the constellation Ursa Minor, is smaller and less prominent than its counterpart, the Big Dipper. It also has seven stars and is famous for containing the North Star Polaris, which had a significant role in navigation.
4. The Big Dipper is larger and brighter, and its stars are more spaced out. Meanwhile, the Little Dipper is a smaller, more compact version of its counterpart and contains many dimmer stars.

References

1. Abel, Paul; May, Brian (2015-01-15). How to Read the Solar System: A Guide to the Stars and Planets. Pegasus Books.
2. Wikipedia - "Big Dipper"
3. Wikipedia - "Ursa Minor"
4. NASA - "What are Asterisms?"
5. NASA - "What are Constellations?"