Two Page Essay On The Little Dipper

The Little Dipper is an asterism in the larger constellation of Ursa Minor, the Little Bear. Asterisms are patterns of stars of similar brightness. The stars may be part of a larger constellation or may be formed from stars in different constellations.

Ursa Minor, though, is almost entirely represented by the Little Dipper. The handle forms the Little Bear's tail, and the dipper's cup forms its flank. The most famous star in the Little Dipper is Polaris, which is currently known as the North Star or Pole Star, as it appears to be aligned with Earth's axis, or Celestial Pole. (It's actually offset by 0.7 degrees, according to NASA.) All of the stars in the Northern Hemisphere appear to circle around Polaris as the Earth rotates, while Polaris remains stationary and is a very useful guide for navigation.

Polaris — also known by its genitive or possessive name, Alpha Ursae Minoris (alpha Mi) — is at the end of the Little Dipper's handle. Along the handle are Yildun (delta UMi) and Epsilon Ursae Minoris (no traditional name). Forming the bowl are Alifa al Farkadain (zeta UMi), Kochab (beta UMi), Pherkad (gamma UMi) and Anwar al Farkdain (eta UMi).

To find the asterism, it is easiest to take the outer two stars in the "bowl" of the Big Dipper and project the line upward in the opposite direction to the "bottom" of the Big Dipper. The two stars will point to Polaris.

The seven stars

The seven main stars of Ursa Minor have been known since antiquity, but further research in the telescopic age nailed down parameters such as their distance, mass and whether the star in question was actually a multiple star. Here are some basics about each one of the stars, mainly according to the website of Jim Kaler, a professor emeritus of astronomy at the University of Illinois.

Polaris (Alpha Ursae Minoris): 323 light-years from Earth and about six times the mass of the sun. The star is a yellow supergiant that has stopped hydrogen fusion; instabilities in the star cause it to pulsate (change brightness slightly) over a four-day period, putting it in the class of Cepheid variables. The star has a smaller companion, an eight-magnitude dwarf that is about the mass of the sun.

Kochab (Beta Ursae Minoris): 131 light-years from Earth, and about three sun masses. Much of its light is sent out in infrared wavelengths. It appears to have a little more barium relative to what is found in the sun, and a little less iron.

Pherkad (Gamma Ursae Minoris): 487 light-years from Earth, and about five times the mass of the sun. The star is relatively young (100 million years old) and when it fuses all its hydrogen, it will turn into a giant similar to Kochab before its outer layers fall off and the remaining core cools, leaving behind a white dwarf.

Yildun (Delta Ursae Minoris): 181 light-years from Earth, and about 3 times the mass of the sun. The star rotates much faster than the sun, finishing an entire rotation in just 19 hours (compared with the sun's 25 days). Otherwise, the star is an average white class A star.

Eps UMi (Epsilon Ursae Minoris): 345 light-years from Earth, and about 3.5 times the mass of the sun. This is a double star (best seen with a spectrograph) where the stars eclipse each other, with a period of about 39.5 days. The sun has ceased hydrogen fusion and is on the way to becoming a red giant.

Akhfa al Farkadain (Zeta Ursae Minoris): 375 light-years from Earth, and about 3.5 times the mass of the sun. It rotates quickly, with a period of 1.5 days. It also may be a slightly variable star, but more investigation is needed to confirm that.

Anwar al Farkadain (Eta Ursae Minoris): 97 light-years from Earth, and about 1.4 times the mass of the sun. The star appears to be close to stopping (or has already stopped) hydrogen fusion. It also rotates quickly, in less than 1.4 days.

History and cultural references

Little is known about how the Little Dipper came to be recognized as an asterism, but Tom Kerss, an astronomer at the Royal Observatory Greenwich, said it likely inherited its name from the Big Dipper. That said, the handle of the Little Dipper is the "wrong" way compared to its bigger cousin, he said. That is, the handle "curves" in the opposite direction.

Sometimes the two asterisms are called "The Kites" in England because they bear slight resemblances to the airborne toys that children play with. The Big Dipper also has been called The Plough or Carl's Wagon, but there are no similar names for the Little Dipper.

Two of the stars in the Little Dipper are nicknamed the "guardians of the pole," Kerss added in a Space.com interview. Kochab and Pherkad, on the far end of the asterism from Polaris, form the outer edge of the dipper's bowl. While the stars are not over the Celestial Pole right now, Kerss said, "three thousand years ago, they were acting as a double pole star. They were in position where Polaris is now, and were fairly close together."

Earth's axis changes over time due to a phenomenon called "precession," which pulls the direction of the axis in a circle that takes 12,000 years to trace out in the sky. What this means is the direction of north changes in the sky over time. "The name was given to them by the ancient Arabs and was relevant for over 1,000 years, when they were near the pole."

Recent astronomical news

While Polaris has been considered a constant beacon for navigators over the centuries, astronomers discovered in 2014 that the star is shining more brightly than before. The star has been known as a Cepheid variable star for many decades, but previously it was dimming since the early 1990s. Newer research then determined the star was brightening again since 2000.

Today, based on observations from astronomers in other centuries, the team behind the 2014 discovery says the North Star is about two and a half times brighter than it was two centuries ago, and perhaps 4.6 times brighter than it was for ancient astronomers.

The year 2014 also saw one of the closest supernovae in years, between the Big Dipper and the Little Dipper. Located in the galaxy M82, the supernova was first spotted by a group of students on Jan. 21 by a group of students led by Steve Fossey at the University College London.

"It was a surreal and exciting experience taking images of the unidentified object as Steve ran around the observatory verifying the result," UCL student Guy Pollack said in a statement.

Additional resources

Do you remember as a child looking into the sky to find shapes in cotton-ball clouds? How often did you see the same shape as someone else? For my family, we saw very different animals or objects, and it was only when we specifically pointed out distinct features that we could agree on a shape.

Similarly, how likely is it for cultures scattered across the globe to see the same shapes in the stars? Ursa Major and Ursa Minor, the Big and Little Bears with distorted tails, are well-known constellations in today’s world because they are easy to spot, hold the asterisms we know as the Big Dipper and Little Dipper, and are important for finding the North Star. Even though these bears have long tails unlike any bear we know today, they caught the attention of the Ancient World as well.

In Roman legend, Jupiter had a lover, Kallisto (or Callisto), who conceived and birthed a son. Jupiter’s wife, Juno, was jealous and cursed Kallisto by turning her into a bear. Years later the son, Arcas, was hunting and came face to face with his mother. Not knowing the bear’s identity, Arcas pulled back an arrow (or a spear in some versions) but Jupiter, to protect Kallisto, intervened and turned Arcas into a bear. To further protect them from Juno’s wrath, he decided to cast them into the sky out of her reach. The weight of the bears as he hurled them into the sky by their tails was enough to stretch the tails into the long ones they have today. Juno, though, found one last way to curse them when she convinced the god of the sea to forbid them to enter the water to rest, so evermore they are forced to wander around the North Pole.1

The Finns, Arabians, Phoenicians, Persians, and inhabitants of northern Asia also call this constellation a long-tailed bear.2 Some say this could be cultural crossover throughout the years, but then why would North American natives see the same picture of a long-tailed bear in the sky, as reported by four early-comers in the late 1600s early 1700s?3

Multiple tribes of the New World, including the Iroquois and Algonquin, have a legend something like this: a giant, magical bear was threatening a village of people and their food. In order to protect themselves, villagers sent their best hunters to track and kill the bear. Mile after mile the bear grew tired; the hunters drew closer until one was able to fatally wound the bear. The bear, in his magic, ran off the earth, straight into the heavens, and took the hunters into the stars with him. As the crimson flow from the wound dripped down onto earth, it turned the colors of the trees red, the mark of autumn. After the hunters spent a winter in the sky, a spirit reentered the bear. The bear rose up, and the chase began again. The hunters killed the bear each autumn, but each spring a new bear came to life to run.

Oceans separate cultures and people, yet so many see the bears in the sky, just as if you and your buddy were looking at clouds and found the same shape. “Thus, circling the globe from the valley of the Ganges to the great lakes of the New World, we find ourselves confronted with the same sign in the northern skies, the relic of some primeval association of ideas, long since extinct.“4

Did this constellation name and idea originate at the same place and from the same people before being scattered throughout the earth?

It begs the question: Did this constellation name and idea originate at the same place and from the same people before being scattered throughout the earth? Claudius Ptolemy in the 2nd century AD meticulously mapped coordinates in ecliptic latitude and longitude for over one thousand stars known to him via legends and his own eyes. Throughout a year, he would have seen all visible stars—winter constellations, summer constellations, and everything in between. Mapping them would have given him a large circle of stars centered at some pivot point. In a time-lapse photo of the night sky, what star does not move? Rather, what point does the sky pivot around? If you answered Polaris (the North Star), you are mostly correct. More accurately, the sky pivots around the North Celestial Pole (NCP), but the North Star is very close to it (less than a degree away). The amazing thing about Ptolemy’s chart is that it does not pivot around the North Star at all! The NCP being somewhere else in the past means it has moved from its position in Ptolemy’s time to now point at the Polaris.

Within the last few hundred years, E. W. Maunder and R. A. Proctor along with others have looked at Ptolemy’s star map and realized the North Celestial Pole is different now because of a phenomenon of physics called precession.

When you spin a top, it rotates quickly around an axis that goes through two points—the handle and where it touches the table. The earth is like a top spinning on an axis, and that axis of rotation gives us 24-hour days—one complete spin. As the top spins, it begins to wobble, looking as if it will fall over. This wobble is centered on a different axis—one from where the tip meets the table, perpendicular through the center of the circle around which it wobbles. This motion of wobbling around an axis, or precession, is due to the force of gravity; the force is due to spinning, or torque. The earth undergoes precession just as a top would because the sun’s gravitational pull on the earth’s equatorial bulge produces a torque. You can imagine the earth’s precession: the axis giving us the 24-hour days traces out a circle in the sky that takes approximately 26,000 years to complete. As the wobble of the earth continues, the NCP (local 24-hour pivot point) moves through the sky. Therefore the North Star will not always be the North Star, nor has it always been the North Star because the earth has been wobbling for ages.

So how does this help us discover when the constellations originated? Using Ptolemy’s map of the stars, Maunder and Procter found the pivot point, NCP, at the time the stars were given to Ptolemy and, using the precession of the earth, traced back to the time the constellations originated. Maunder explains this process and comes to the conclusion that constellations began around 2,800 BC.5 Procter came up with the date 2,100–2,200 BC.6 Using similar methods and Ptolemy’s map again, “Maunder considers that the designers of the figures lived, in all probability, between 36° and 42° north latitude.”7 Others have done the same calculations, and all converge on dates in the third millennium BC in latitudes between 30° and 42° north.8

What does this mean for us today? Well, for those who believe in a land bridge between Asia and Alaska 10–12,000 years ago, it presents the problem of how people developed the same constellations as absurd as two long-tailed bears. The fact that some cultures across the globe have the same constellations in their night sky supports the idea that all people groups once were together sharing information. But if people did not develop the constellations until the third millennium BC, then how did Native Americans see two bears in the sky, as did people in the Old World, when the physical link between the Old World and the New World was severed thousands of years earlier?

The time period for the origin of the constellations as we know them in the third millennium BC coincides with the biblical timeline.

Interestingly, the time period for the origin of the constellations as we know them in the third millennium BC coincides with the biblical timeline. The Flood and Tower of Babel were in the third millennium BC. Furthermore, the latitude range of the origin of the constellations agrees with the biblical location of the post-Flood society on the Plane of Sumer. If the constellations developed at that time, then as people dispersed after God’s judgment at the Tower of Babel, they would have taken the constellations with them. Thus the land bridge connecting Asia and the Americas existed much later in the biblical chronology than in the secular chronology. Though modifications in the constellations were inevitable, one would expect some common elements, such as the two bears, to persist.

It is improbable that more than one culture would have developed two long-tailed bears among the constellations independently. It is far more likely that similarities between different constellation systems is the result of a common origin rather than a coincidence. Hence the presence of Ursa Major and Ursa Minor in the constellations of diverse cultures bears testimony of the reliability of biblical history at the earliest epochs of post-Flood and post-Babel human migration.

Brooke C. Nelson wrote this while at Answers in Genesis as an intern with Dr. Danny Faulkner during the summer of 2016.

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