When the sun sets, constellations and shooting stars come out to shine. They share tales of old, carry the origins of the galaxy across the cosmos, and play a vital role in our past, present, and future.
Part of this vast wealth of knowledge has been mapped out by ancient astronomers who created celestial globes. These globes originated long before planetariums and satellites; they were our first spherical maps of the sky.
Celestial Globes
Designed and mapped with the Earth in the center of the universe, celestial globes were first designed by ancient Greeks in the 6th Century BC. Celestial globes map the stars in the night sky by placing them in constellations relative to how they would appear to humans viewing them from Earth. Dots, stars, or holes often mark individual stars. Should the globe be equipped with an opening to insert a light source, the stars would be projected upon a dark surface, making a rudimentary planetarium.
Many incarnations of celestial globes have been made over time, and our modern take is the MOVA Constellations Globe (pictured above). This globe maps the 88 constellations recognized by the International Astronomical Union with silver-toned dots, star shapes, and lines over a deep black — and always cloudless — night sky.
What Are Constellations?
There are billions of stars in the night sky, and for centuries humans around the globe—from the ancient Greeks and Romans to Native American, Asian, and African cultures—have grouped stars into pictures. These pictures are known as constellations and have shared stories and religious significance throughout history while also providing navigational aid to sailors and seasonal planting reminders to farmers. Their combined stories help shape our history on Earth.
Today, there are 88 officially listed constellations. The most well-known are Orion, Ursa Minor, and Ursa Major. You might be tempted to name the Big Dipper in that list. However, while it is universally the most recognized star pattern, it is not a constellation! It is an asterism (or prominent group of stars) that forms part of Ursa Major.
The stars in a constellation do not share the same plane in space. Their distances vary by millions of lightyears. Additionally, the brightness of a star does not determine its distance from Earth. Brightness is directly related to the size of a star. So, the brightest stars can be some of the furthest in a constellation.
The rotation of the Earth affects our ability to see certain constellations at different times. Farmers used these changes to determine when to plant and harvest. This also means that the stars remain fixed in space while we move. The North Star is a prime example. No matter where you are in the Northern Hemisphere, the North Star is visible and fixed above the North Pole. Therefore, following the North Star will always lead you north.
The Stories Constellations Share
Each constellation has a name and a story tied to it. Some are rooted in mythology, while others are linked to religion or relate to astrology.
Some famous examples include:
Andromeda: Andromeda was born to Cassiopeia and King Cepheus, and to appease the gods, she was chained to a rock to be fed to a sea monster. Thankfully Perseus was so captivated by Andromeda’s beauty he saved her. So great is their story; it lives on in the night sky forever.
Crux (Southern Cross): Having slight variations across different cultures, the cross is traditionally seen to have biblical significance with the crucifixion of Jesus. Farmers also used the Southern Cross to signal the start of planting season as it came into view in the late spring.
Ursa Major (Great Bear): This constellation relates to Greek mythology and is referenced in the Old Testament, and contains the Big Dipper. The Big Dipper is used by many as a navigational guide to finding the North Star. Enslaved people even used it in their search for freedom around the time of the Civil War.
History of Shooting Stars
Stars are not the only celestial bodies visible in the night sky. For millennia, people have looked up, hoping to see a shooting star. Their seemingly random and fleeting appearance in the night resulted in a wide range of theories about their existence.
A Native Americans viewed shooting stars as a foretelling of war. Ancient Greeks believed so profoundly in the power of shooting stars they named Asteria the goddess of shooting stars. Today, we are familiar with their symbolism and the saying that one should “wish upon a shooting star.”
The Science of Shooting Stars
In scientific terms, shooting stars are meteors. They leave a streak across the night sky as they burst into flame from the heat of the Earth’s atmosphere. Meteors were meteoroids—tiny bits of asteroids or comets—that carried the universe’s origins in their rocky mass. As the meteors break free from larger asteroids or comets, they fall out of orbit and go careening about the solar system until they collide with another planet or burn up on entry into their atmospheres.
Meteor showers are celestial events in the night sky when several meteors (shooting stars) enter the Earth’s atmosphere at once or over a few hours. Meteor showers are caused by the trail of debris left by comets as they pass in orbits near the Earth, making their arrival predictable with the use of science and technology. Astronomers use this information to create calendars of dates and locations where meteor showers can be best observed.
Whether you believe in their myths and legends, use them for navigation, or simply enjoy finding them on a constellation globe and in the night sky, constellations and shooting stars will continue to bring people together as we learn about them our past and dream of our future.
