Welcome to my blog, haru_space! I am so excited and so thankful you are reading this. Although I would love to get deep into all the fascinating findings, theories, and observations that ultimately cultivated my personal love for outer space, we have to start with the foundation of the subject itself.
First, let’s start here.
What is astronomy?
If said briefly, it is the study of everything beyond the Earth’s atmosphere, such as the phenomena and celestial objects in the sky. There are plenty of astronomers worldwide, but they don’t always study the exact same thing. Some may study nearby objects such as the sun or the moon, while others may study objects light-years away, such as black holes and distant galaxies.
So technically, if you are interested in the night sky and you are studying it, then you’re technically an astronomer…
What do astronomers do?
One thing astronomers do is use electromagnetic radiation* from space and scientifically analyze the data collected by their instruments.
*electromagnetic radiation: all of the types of radiation included in the electromagnetic spectrum
To get their findings, astronomers use many different types of telescopes - these telescopes are each in charge of a specific type of electromagnetic radiation. After they collect data, they convert it in to a format which humans can see.
For example, radio telescopes will catch the radio waves and amplify or make the waves large enough to create a visible image from them → the radio waves get converted into an image with visible light!
The telescopes can also be ground-based or up in space, with each having different reasons for the location!
Telescopes may be more ideal up in space because:
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There is no light pollution*
Light pollution: lights from human-made structures such as streetlights or houses emit light into the sky, making it harder to observe stars
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There is no atmosphere.
There is no chance for disruption/distortion of the light coming from space. The clouds or the air molecules will not obscure the telescope’s view if it is already above the atmosphere.
When we see a star on a clear night, it’s not at its clearest state. Molecules in the atmosphere can interact and bump into the light, distorting it.
But this is also the reason why stars twinkle!
How do telescopes work?
There are two main types of telescopes.
- Reflector telescope: This type of telescopes are larger and more popular with modern telescopes. It works by reflecting the incoming light with the mirrors inside the telescope (hence the “reflector” in the name), and the reflected light is then magnified by the eyepiece, and the viewer is able to see the image.
- Refractor telescope: This is more common in ancient telescopes, and in modern times, it is used on smaller/made-for-kids type of telescopes. It works with the lens, which is inside the telescope, refracting the incoming light from the sky. The refracted light is then magnified by the eyepiece (similarly to the reflector telescope). Currently, modern professional telescopes are not refractor telescopes because the lenses are expensive to make, extremely heavy, and the refraction process takes up a lot more space.
What are different branches of astronomy? How does astronomy relate to other subjects?
To put it simply, astronomy is a specialized field of physics. Because physics explains the way the world works, it has clear connections to other science subjects, such as chemistry, biology, and even archaeology. All of these subjects team up to answer the most fundamental questions that humans have, such as…
- How do stars form?
- What is dark matter?
- What was going on in the early universe?
- Is there life beyond Earth?
Here are some of the different branches of astronomy:
- Astrometry - This is a very mathematics-based branch, and it is the oldest branch ever known. Measuring the positions and motion of the objects in the sky, astrometry is able to calculate a variety of things; for example, it can compute the moon, a certain planet, and Earth’s motion to help predict eclipses.
- Astrobiology - You would think biology would have been the furthest field of study from astronomy. This is a newer field of astronomy and deals with the essential question “Is there life beyond Earth?” It may loop in geology, chemistry, and other subjects to predict the chances of life existing beyond our planet.
- Cosmology - Cosmology consists mainly of physics and theories, and according to NASA, it is “the study of the large-scale properties of the universe as a whole”. Some topics cosmologists may research include the origins of the universe, the function of the universe, and its composition.
- Astrophysics - Astrophysics is an interchangeable word between astronomy. It uses physics and math to apply laws to explain the behavior of celestial objects. Instead of studying the universe as a whole like cosmology, it may focus on one specific phenomenon or object, such as a star or a planet, in the universe and explain its behavior.
- Astrochemistry - This is the study of the composition and molecular behavior of celestial objects. It poses the question of the object’s behavior and relates it to its behavior in space and how it can affect its functionality.
How did ancient civilizations use astronomy to their benefit?
Let’s just say that astronomy can be dated back as far as 1000 BCE (considered to be one of the oldest subject in the natural sciences), and it has some of the oldest artifacts related to science.
As some of you may be aware, ancient civilizations used stars to track time and navigate themselves. Before clocks and calendars were invented, the stars’ movements were used for agriculture and predicting seasons; in fact, the very first astronomers made calendars by observing the phases of the moon. They could also navigate themselves by the stars’ locations, as it was used for directions, and many memorized constellations as well.
Fun fact: We know Polaris as the North Star of today. However, in the ancient skies, the stars were at different positions, meaning that Polaris did not actually point north for them, and they used a different star to guide them instead!
And that is the end! Thank you so much for reading until the end, and I hope that this blog helped you get an overview of astronomy. I hope you enjoyed, and stay curious!
Haru
Sources:
“A History of Astrometry - Part 1 Mapping the Sky From Ancient to Pre-Modern Times.” European Space Agency. Updated 1 September 2019. sci.esa.int/web/gaia/-/53196-the-oldest-sky-maps. Accessed 10 July 2024.
“Astrochemistry.” Center for Astrophysics. cfa.harvard.edu/research/topic/astrochemistry. Accessed 10 July 2024.
Carter, Jamie. Pultrarova, Tereza. “Astronomy: Everything you need to know.” Space.com, Last updated 26 July 2023. space.com/16014-astronomy.html#section-type-of-astronomy. Accessed 6 July 2026.
“Constellations.” Royal Museums Greenwich. rmg.co.uk/stories/topics/constellations. Accessed 6 July 2026.
Harvey, Ailsa. Tillman, Nola Taylor. “What is cosmology? Definition & History.” Space.com, Published 21 February 2022. par. 1. space.com/16042-cosmology.html#section-history-of-cosmology-astronomy. Accessed 6 July 2026.
“What is Astronomy?” American Museum of Natural History, amnh.org/explore/ology/astronomy/what-is-astronomy. Accessed 6 July 2026.
Zacharias, Norbert. “Astrometry.” Scholarpedia. Updated 10 March 2011. http://www.scholarpedia.org/article/Astrometry#:~:text=Astrometry is the science which,until about the 19th century. Accessed 6 July 2026.
