What is astronomy?
Every night, using the science of astronomy, the entire universe can be revealed above us. Although at some point we've all had that "blanket of stars" moment, it is an illusion. The visible planets and the bright stars you can see with your eyes are mostly very close to us — in cosmic terms — but the night sky has incredible, almost unfathomable depth. Not only can our own galaxy, the Milky Way, be navigated and known but other galaxies can be probed using telescopes, on Earth and in space, and in various wavelengths of light from all kinds of cosmic objects.
Here’s everything you need to know about what astronomy is, what it’s not, and how recent developments within the field of astronomy are making it more exciting than ever before.What does astronomy mean? A dictionary will tell you that it’s the branch of science that deals with celestial objects, space, and the physical universe as a whole. Astronomy is the study of everything in the universe that’s beyond our own planet’s atmosphere. The planets in our own solar system, our own star the sun, and the bright stars can all be seen with the naked eye. However, astronomy can go much deeper, taking advantage of telescopes and other scientific instruments to study other stars and their planets in our galaxy, as well as distant galaxies beyond our own. It can gather clues about the nature of the physical, chemical and biological universe itself.
Astronomers aren’t stargazers. Or, at least, there’s no longer any need for them to be. If you think an astronomer treks up mountains to spend night after night behind the eyepiece of a giant telescope, think again. These days telescopes can be controlled remotely, so it’s common for modern astronomers to simply make requests for observations and then download computer-generated data and images the next morning for their analysis. That includes space telescopes like the Hubble Space Telescope.
People very often confuse astronomy with astrology. Every professional astronomer has had to hear someone say to them, "so you’re an astrologer, right?" Astrology and astronomy are not the same thing, but they used to be. Observational astronomy can be traced back to Ancient Egypt and Mesopotamia as far back as 3,000 B.C., but the calculating of solar eclipses, the movements of the planets and theories about how the night sky works was the job of ancient astrologers who presumed that celestial events and alignments had a direct impact on human affairs.
Modern astrologers attempt to do something similar, making predictions about human lives based on pseudoscience. Astrology is not a science. n the past century or so, astronomy has been broadly split into two camps — observational astronomy (using telescopes and cameras to collect data about the night sky) and theoretical astronomy (using that data to analyze, model and theorize about how objects and phenomena work).
They complement each other, yet within these two broad categories modern astronomy includes many subsets, from astrometry to exoplanetology, that intrinsically overlap yet help explain the many things astronomers do. Here’s what they all mean:
Astrometry: This ancient branch of astronomy concerns precise calculations of the motions of the sun, the moon and the planets. It includes predictions of solar and lunar eclipses, and meteor showers. It also includes exoplanetology, a relatively new and very exciting field that concerns itself with the discovery and characterization of planets outside of the solar system.
Planetary astronomy: How did the solar system come to be? This is the central question penetrating planetary astronomy, which focuses on the formation, evolution and death of planets, moons and other objects. In the solar system it also includes planetary geology.
Astrophysics: Astrophysicists apply the laws and theories of physics to astronomical observations. It’s an attempt to understand the mechanism behind how the universe was created and how it has and will evolve.
Astrochemistry: Astrochemists study the composition and reactions of atoms, molecules and ions in space.
Astrobiology: This emerging and, for now, largely theoretical field of astronomy is the study of life beyond Earth.
Stellar astronomy: The study of the life cycle and structure of the sun and the stars, stellar astronomy concerns the classification of stars, and populations of stars.
Solar astronomy: Galactic astronomers study our galaxy, the Milky Way, while extragalactic astronomers peer outside of it to determine how these groups of stars form, change and die.
Cosmology: Although it’s sometimes used to mean astronomy, strictly speaking, cosmology refers to the science of the origin and nature of the universe. The key concept in cosmology is the Big Bang Theory, the most widely accepted explanation of how the universe began. Cosmology also includes purely theoretical subjects including string theory, dark matter and dark energy, and the notion of multiple universes.
