Astronomy - The Basics
Astronomy is the study of the universe and everything that is in it. Astronomers use scientific methods and tools to gather facts and valid evidence in order to interpret or describe the matter that is in space, including the Sun, Moon, planets, and other bodies in the Solar system. Astronomy is a division of science, which uses measurable and identifiable observations to formulate and test predictions about the natural world within established laws and theories.
How can astronomers logically inquire about the unknown or unobservable in space? Astronomers use what they do know about the known world and relate it to the unknown. By using the laws of physics, scientists can generate hypotheses that explain the unknown and unobservable. To do this, a scientist has to make a hypothesis based on what is already known from the laws of physics.
For example, the Big Bang Theory and Solar Nebula Theory are hypotheses of how the universe and the sun were formed. According to some scientists, about 13.7 billion years ago, an extremely hot and dense state of matter and energy suddenly emerged from the singularity. This hot and dense state expanded rapidly in all directions as it cooled over billions of years. Gradually, the cooling matter and energy formed the elements that would become galaxies, stars, and eventually, planets like the Earth and its vast oceans. A portion of this hot and dense matter coalesced into a spiraling cloud of superheated hydrogen gas and dust. Scientists call this a solar nebula and it is from this that the sun was formed through nuclear fusion. By using what is already known of the nature and the laws of physics, scientists form these hypotheses. By using physics to measure the distance and speed of moving objects, scientists theorize that everything in the universe was once joined in a hot and dense state of matter approximately 13.7 billions years ago.
The Difference Between Astronomy and Astrology
An antique zodiac calendar
Astrologist also make observations and predictions regarding celestial matter; however, astrology does not rely on founded theory or facts known about the universe. Considered a pseudoscience, astrology has roots in ancient times and is still practiced today. Astrologists divide the the sky into twelve divisions or sectors of a circle, with each division measuring 30 degrees. You may know the names of these divisions already: Aries, Taurus, Gemini, Cancer, Leo, Virgo, Libra, Scorpio, Sagittarius, Capricorn, Aquarius, and Pisces. Astrologists use these fixed divisions to determine the placement of such celestial bodies as the sun, moon, and planets. Astrologist believe the placements of the sun and moon within the astrological circle have influence on life on Earth.
In order to make observations about the universe, astronomers start with the basics of astronomy. These basics form the foundation for the science and the study of the universe. View this presentation to learn more about the basics of astronomy. Click the player to begin.
Download a printable version of the interactivity.
The size of the universe is immense. In order to learn more about the universe, scientists must be able to work with huge numbers representing the vast distances in space. Watch the video Measuring Distance in the Solar System from eMediaVA℠. While watching the video, consider the following questions:
- Which numbers would you prefer to work with, the very large numbers or those written out in scientific notation? Why?
- Explain why we need such large numbers, but we rarely use or hear of these numbers dealing with everyday life.
Astronomy - The Basics Review
Now that you have learned the basics of astronomy, review your knowledge in this non-graded activity. Read each statement and select the correct answer to fill in the blank. Then, click SUBMIT to check your response. Click the player to get started.