What is astronomy?
Every one of us is an astronomer, in a sense. Every time you look up and see the stars, you’re doing astronomy, just like humans have done for thousands of years. Let’s give astronomy an official definition. Astronomy is the study of everything that lies beyond the Earth’s atmosphere. That’s a lot of stuff. The Celestial Sphere Here’s a little something to help us put the heavens in perspective the celestial sphere. When people first started looking at the sky, they imagined that all those little lights out there were hanging on the inside of a large bowl. Well, not so much a bowl, really, but a sphere that surrounded the Earth. We call that imaginary sphere the celestial sphere. All the stars are on the surface of the imaginary celestial sphere and the Earth is inside in the center. Now, we know that all the stars and planets and everything are different distances from us, but the idea of the celestial sphere is still convenient for pinpointing things in the sky. To use the celestial
That’s easy. Astronomy is the study of Outer Space. Why should we study Outer Space? We study Outer Space because we are part of it. That’s right. You are part of outer space, everything is. We live on Earth. Earth is part of Outer Space. The Earth circles the Sun. The Sun is a star, and just like all the other stars it is part of Outer Space. Lets talk about the how Astronomy became a science. 400 years ago humans began to really understand the Universe. Before then, many people thought the Universe was a giant glass ball which circled the Earth. They thought the stars were holes in the glass where light from heaven could shine through. And that everything in the Universe circled around the Earth. In 1607 a man named Galileo changed the way we view the sky. Galileo used a telescope and for the first time saw what the Universe really was. The most important thing he saw was that Jupiter had moons. This meant that everything did not circle the Earth. Galileo could prove to others that t
Astronomy is the study of celestial objects, phenomena, and origins. One of the oldest sciences, astronomy has been practiced since prehistoric times. Modern astronomy depends highly on accepted physical theories, such as Newton’s Laws of Motion and general relativity. In the past, astronomy was something anyone could do, and many seers and sages made reputations for themselves by using the stars for useful functions, such as telling what time of the year it is, or navigating the seas. Columbus and his contemporaries used the stars to navigate across the Atlantic ocean. It wasn’t until the Renaissance that the theory of heliocentricity in astronomy, the idea that the Earth orbits the Sun rather than vice versa, began to acquire popular currency. Telescopes were invented in 1611 by Galileo Galilei, and he used his to take detailed observations of our Moon, which he revealed was mountainous, and observe Jupiter’s four largest moons, now named the Galilean moons in his honor. Newton impro
Good question and if you’re coming here you might be wondering. Maybe we should start with what astronomy isn’t. Astronomy is not the same thing as present day “astrology”. Astrology is an old practice, which has many different levels. I won’t pretend to be that knowledgable about it because I’ve never been involved with it, but its clear that there are many different levels of astrology, from pulling your horoscope from the newspaper to people that attempt to predict things by positions of planets and stars as they relate to each other. That’s where I’ll leave it. Astronomy is a big thing. Astronomy IS the study of the cosmos, at all levels. It is the investigation of life on Mars; using large telescopes to peer back in time to see galaxies merging; figuring out what Jupiter is made out of; finding planets around other stars by observing the change in the star’s spectrum as the planets orbit around it; and much, much more. Ask an amateur (or professional) astronomer what your horoscop
Astronomy is the science dealing with all the celestial bodies in the universe, including the planets and their satellites, comets and meteors, the stars and interstellar matter, the star systems known as galaxies, clusters of galaxies, and quasars. Astronomy is such a broad topic that astronomers specialize in one or more parts of the field. For example, the study of the solar system is a different area of specialization than the study of stars. Astronomers who study our galaxy, the Milky Way, often use techniques different from those used by astronomers who study distant galaxies. Many planetary astronomers, such as scientists who study Mars, may have geology backgrounds and not consider themselves astronomers at all. Solar astronomers use different telescopes than night time astronomers use, because the Sun is so bright. Theoretical astronomers may never use telescopes at all. Instead, these astronomers use existing data or sometimes only previous theoretical results to develop and
