How and why was the universe born? Astronomy is known to be one of the first natural sciences developed by early civilizations worldwide, although ancient astronomers were limited in their investigations of the sky. 

Over time, people have wondered why the seasons change from summer to winter, why the moon has different phases throughout the month, how the stars align and barely shift, or how solar eclipses occur. This curiosity began as far back as the Babylonians.

Let’s explore the history of this discipline and how it has evolved from using the moon, sun, and stars to track time to be a key part of religious, cultural, and agricultural practices. 

Early Astronomy

Let’s dive into where astrological theories began, starting with the 3rd Century!

3rd Century BCE

Ancient Greek philosophers documented that the Earth was a sphere. The night sky looked different from various Earth locations, hinting at our planet’s curved surface. 

They also observed the moon’s round shadow during lunar eclipses, enabling them to accurately measure the circumference of Earth.

6th Century BC

Ancient Greek philosophers documented that the Earth was a sphere. The night sky looked different from various locations on Earth, and this hinted at our planet’s curved surface. 

They also observed the round shadow of the moon during lunar eclipses, able to accurately measure the circumference of Earth.

185 BC

Chinese astronomers were the first to document a Supernova, and in the year 964, our neighboring Andromeda galaxy was observed by a Persian astronomer, who described it as a “nebulous smear”. In star charts, Andromeda was known as a “little cloud”.

Before the 16th Century, Earth was believed to be at the center of the Solar System, with every other planet revolving around it (also called the Geocentric Model).

1543

Polish astronomer Nicolaus Copernicus put forth the Heliocentric Model of the Solar System, where the planets orbit the sun, which isn’t true today. This theory was one of many revolutionary ideas about astronomy that emerged during the Renaissance period.

Astronomers Tycho Brahe and Johannes Kepler realized an on-point description of planetary motions, creating the foundation for Isaac Newton’s gravitational theory! 

1609

Genius astronomer Johannes Kepler published a book in Heidelberg called Astronomia Nova, recording the first two laws of motion of the planets. He discovered the elliptical orbits of Mars and the other planets around the sun.

Influenced by Copernicus and his teacher Michael Maistlin–a heliocentric–Kepler relied on long-term, accurate, and credible observations of the Danish astronomer Tycho Brahe. He gave the laws that have ruled our planet since:

The first law: the planets erase around the sun’s elliptical orbits which the sun holds.

The second law: They are erased from the planet at equal times in equal areas.

17th Century

Previous astronomy investigations were strengthened by the invention of the telescope in the early 17th century. 

Italian astronomer and Scientist Galileo Galilei popularized telescopes to study and discover celestial objects, such as Jupiter’s four biggest moons.

In 1609, Galileo observed the mountains and valleys of the moon, the nature of our galaxy, sunspots, the planet Saturn with its ring, and the four satellites of Jupiter. His observations radically changed the worldview of his time.

1923

In 1923, Edwin Hubble changed the scientific view of the universe when he used the 2.5-metre diameter hooker telescope to prove the Andromeda Nebula extends beyond our Milky Way galaxy.

Greek Astronomy 

Applying geometry to solve astronomy problems, Aristotle on the Heavens supported the claim that Earth was a sphere. 

Aristotle mentioned how Earth’s shadow–as seen on the moon during a lunar eclipse–is circular. He also mentioned the visible changes of the stars, as one moves from north to south on Earth.

Astronomy Beliefs Changing

Instead of single planets revolving around the sun, moons revolve around the planet. As a heliocentric follower of Nicholas Copernicus, Galileo realized this. 

The phases of Venus–which showed this planet orbits the sun–and the four satellites of Jupiter, now called Galilean, proved that the moon was not the only case. This destroyed the belief that all celestial bodies revolve around the earth, laying down the foundations of modern astronomy.

Thanks to the construction of perfect telescopes, astronomers have slowly managed to reconstruct the universe’s history. Astronomy’s progress over the last 400 years has provided answers to questions from millennia, putting an end to many kinds of superstitions.

Eclipses are alignments of celestial bodies and comets, and likewise for asteroids–also known as “dirty snowballs” by astrophysicist Fred Whipple in 1950.

Babylonian astronomers in the first and second millennia BCE tracked five points of light in the night sky that moved differently from other stars; these five points weren’t stars at all. Today, it is believed that Babylonians were among the first to recognise the planets Mercury, Venus, Mars, Jupiter, and Saturn, which were visible to the naked eye at different times of the year.

Present Day

Today, astronomers collect data on celestial objects using huge telescopes on the ground as well as in space. 

Hubble’s discovery of the universe’s continuous expansion paved the way for other astronomers to theorize its origin.

Debunking The Big Bang Theory

The Big Bang Theory–proposed by Georges Lemaitre–was later destroyed by strong evidence: the discovery of the cosmic microwave background (CMB) or “faint” noise leftover from the massive explosion that rose everything in the universe. 

CMB was accidentally discovered by radio astronomers five years before the 1969 Apollo 11 Moon Landing. These more modern telescopes equipped with big mirrors allow astronomers to capture light from very faint and faraway objects. 

Powerful Telescopes and Techniques

Specialized techniques and sensitive scientific instruments have been developed to study not only visible light but the electromagnetic spectrum of light, including infrared light, radio waves and X-rays.

Larger, more complex telescopes and techniques have allowed astronomers to directly observe black holes, distant exoplanets, and gravitational waves. These improvements let astronomers collect even more data about planets within our solar system in the second half of the 20th century.

Many robotic space campaigns–including Mariner, Venera, and Voyager–have ventured farther than ever before.

Astronomy – An Ever-Changing Science

From astrophysics to astrogeology, astronomy started by counting stars to charting constellations, and now it is so much more. Through its development over thousands of years, scientists to this day are trying to understand the nature of the universe.

Although we may never truly grasp dark matter, black holes, supernovas, white dwarfs or neutron stars, there is one thing for certain: space is full of endless possibilities, with courses like the online Master of Science in Education now preparing people to teach STEM subjects in classrooms and helping build on the scientific foundations of the past to go above and beyond what we understand on Earth.

Published by: Khy Talara