Learn about Astronomy

When you look at the sky during the night, are you fascinated by the stars?

Thousands of years ago, our ancestors were also fascinated by the night and day skies. They gave names to different stars and planets and they created stories about them. For instance, in Greek mythology, the sun is said to be a god named Apollo, while the moon is said to be a goddess named Diana. Diana and Apollo are supposed to be twins. Today, this fascination with stars is still alive. However, instead of myths, a science called astronomy has been developed not just to study stars but also other celestial or sky objects such as planets, galaxies, comets, star clusters and nebulae.

What is astronomy?

Astronomy is classified as a natural science that studies celestial objects and phenomena or events that occur outside our planet’s atmosphere. It uses other sciences like physics, chemistry, and meteorology to study the formation, development and motion of the universe and its components.

How did astronomy develop?

Astronomy is considered one of the earliest sciences. This is evident from the artifacts left behind by ancient civilizations such as the Stonehenge in England and the monuments in Egypt. Based on archaeological discoveries, the Maya, Indians, Chinese, Babylonians and Greeks were already observing the night sky thousands of years ago. However, it was only when the telescope was invented that astronomy became a modern science. Prior to the invention of the telescope, astronomy included various disciplines such as astrometry, astrology, calendar-making and celestial navigation. Astrometry is the science that maps out the positions of planets and stars. Today, astrology, the system which uses the positions of stars and planets to predict human affairs, is not a part of astronomy. In fact, astronomy is sometimes called astrophysics, giving emphasis to its scientific foundations.

What were the contributions of various civilizations to astronomy?

During the time of the Babylonians, the cyclical nature of lunar eclipses was discovered. This repeating cycle was called “saros”. During the time of the ancient Greeks, a rational explanation for the movement of stars and the changing of night and day was sought. Aristarchus of Samos was able to calculate the size of the Earth and the respective sizes and the distances of the Moon and Sun from the earth. Hipparchus developed the first astronomical device called the astrolabe and cataloged about 1020 stars. During the Middle Ages, medieval Europe did not make significant developments in astronomy. However, in the Islamic world, astronomical observatories were built. The discovery of the Andromeda galaxy, which is the nearest galaxy to our own Milky Way galaxy, is attributed to a Persian astronomer named Azophi. Other Muslim astronomers who had significant contributions include Albumasar, Arzachel, Al-Birjandi and Biruni.

What were the scientific developments in astronomy during the Renaissance?

There were many changes that occurred during the Renaissance. Copernicus proposed the heliocentric theory, which states that the sun is the center of the solar system. This Copernican theory was defended and further explained by the great scientists Johannes Kepler and Galileo Galilei. Galileo Galilei was able to use a telescope to come up with his observations but he was imprisoned because his belief was not the same as that of the prevailing doctrine of the Catholic Church. Afterwards, Isaac Newton came up with the laws of motion to explain the motion of celestial bodies, including the planets and the sun.

What is observational astronomy?

Observational astronomy is the use of visible light and the other types of electromagnetic radiation in order to gather information regarding celestial objects. The divisions of observational astronomy are based on which part of the electromagnetic spectrum is utilized.

• Radio astronomy. In radio astronomy, wavelengths of radiation more than 1 millimeter are used for observation. Celestial objects which are observed in radio astronomy include supernovae, pulsars, active galactic nuclei and interstellar gas.

• Infrared astronomy. Infrared radiation refers to radiation with wavelengths greater than that of red light. Because the earth’s atmosphere produces significant amounts of infrared radiation, infrared astronomic observatories have to be situated either in high and dry places or somewhere in space. Infrared astronomy is useful for studying celestial objects too cold to emit radiate visible light like planets, circumstellar disks, galaxy cores, and water in comets.

• Optical Astronomy. Optical astronomy refers to the study of celestial objects in the range of visible light. This means that astronomical observations are made using the human eye and telescopic aids. This is the oldest type of astronomy and this is what you practice when you observe the night sky with or without a telescope.

• Ultraviolet astronomy. This type of astronomy is used to observe ultraviolet wavelengths and is best for studying thermal radiation and hot blue stars.

• X-ray astronomy. This type of astronomy uses X-ray wavelengths. Celestial objects that emit X-rays include elliptical galaxies, pulsars and supernova remnants.

• Gamma-ray astronomy. This type of astronomy studies the emissions of celestial objects with the shortest wavelengths. Special telescopes named atmospheric Cherenkov telescopes are used for this type of astronomy. It studies celestial objects like black holes, neutron stars and pulsars.

With astronomy, you are able to explore the wonders of the universe, including the planets, the stars, the galaxies, the supernovae, the black holes and the many unknowns out in space. If you are interested in astronomy check out this website: www.solarsystemscope.com. It was put together by a group of astronomy fans and they have made very user-friendly interactive 3D model of the solar system and the night sky with real-time planetary positions. Use it to help kids understand science further, particularly the movements of the planets and to recognize constellations. Or alternatively for the price of a cup of coffee, why not download our engaging e-book Introduction to Astronomy e-book to launch your child’s love for science!