It is much harder for us to understand the universe as we know it today than it was for ancient man to grasp his idea of the universe. Today we consider the universe to include not only the earth and our solar system,
but the Galaxy to which this solar system belongs (called “the Milky Way”), and all the other galaxies as well. There are some 200,000,000,000 stars in just our own galaxy—and there are millions of other galaxies stretching out into the universe. Man’s imagination just cannot grasp this vastness!
But in ancient times, they had a very simple picture of the universe. They thought that the sun, moon, stars, and planets were small objects moving around the earth. They believed that the universe was as it appeared to them—with a vast, flat. immovable earth in the center and a great do„me overhead, sprinkled with thousands of little shining lights.
The Greeks started the true science of astronomy. Most of the ancient Greeks thought that the earth stood still in the center of the universe. Pythagoras, who lived in the sixth century B.C., seems to have been the first to suggest that the earth is a sphere. But he still thought it was the center of the universe and did not move.
Aristarchus, who lived in the third century B.C., believed the earth was a sphere that rotated on its axis and revolved around a stationary sun. In the second century A.D., an astronomer named Ptolemy wrote a book called the Almagest. He thought the earth was the center of the universe, and he tried to show how the planets, the sun, and the moon moved around the earth. His ideas were accepted for 14 centuries.
Copernicus, in 1543, suggested the sun as the center of the universe. Then came the discovery of the telescope and man had a better means of finding out what the universe is really like. As more and more facts were gathered, our modern idea of the universe was gradually developed.
What Tools Do Astronomers Use To Study The Universe?
1. Cameras. Hubble’s scientific instruments analyze different types of light ranging from ultraviolet (UV) to infrared (IR).
4. Past Instruments.
Ancient people were intrigued by the sky, and they understood how it worked much better than we do today. Their methods of observation, though, were quite primitive—they relied on the shadows of objects to see the night sky and had no knowledge of depth perception because their eyes were on the side of their head. Ancient astronomy was, quite simply, a way of life for ancient peoples. The science they developed was used for navigation, agriculture, and predicting seasonal patterns.
Although the planet Earth has been home to humans for a few hundred thousand years, the idea that the planet is a planet and not just a solid ball of rock and ice has been around for a lot of time. The Ancient Greeks believed in the spherical Earth, while the ancient Egyptians believed it was flat. The Greek philosopher Thales, around 600 BCE, even proposed that the Earth was round. Others, like Aristotle, rejected this idea, saying the Earth was the center of the universe.
The ancients used to believe that the planets were gods, living beings, and not just small objects orbiting the Sun. They believed that planets moved around the Earth, and they also believed that some planets had their own moons. In the middle ages, the planets became objects of study, but it wasn’t until the 17th century that the planets began to be viewed as the “fixed” objects we know them as today.