Theoretical Vs. Observational Astronomy

Comet NEOWISE over Stonehenge

Astronomy is one of the oldest existing sciences, started when humans first looked at the night sky. The study of the sky is split into two main parts, observational astronomy and theoretical astronomy. Observational astronomy deals with the study of electromagnetic radiation from space. This simply means taking photos of the sky and then analyzing these photos. Theoretical astronomy uses tools of physics and chemistry to create analytical models. This branch tries to explain why things happen.

How do these branches work together?

The two branches complement and support each other with their results. Observational astronomy verifies predictions made by theoretical astronomy. Observational astronomy also observes new and interesting events. Theoretical astronomy explains events seen in observational astronomy.

One recent example of this is the dimming of Betelgeuse. First, Observational astronomers noticed that the red giant Betelgeuse was brightening and dimming rapidly. Then, theoretical astronomers came up with the theory that a gas cloud was causing the star to behave so strangely. Together, these two branches were able to find a strange occurrences, and the explain it.

How we think Betelgeuse brightened and dimmed.

Which study is better?

Both fields are extremely important! Without observational astrophysics, we would not be able to know what was happening in the universe. Without theoretical astrophysics, we would not be able to understand why events happen in the universe. Most great theories come out of both theoretical and observational astrophysics!

For example, Einstein theorized that gravity could bend light. A couple of years later, astronomers were about to prove that theory right by looking at a solar eclipse. 

A total solar eclipse like the one used to prove Einstein right.

Which study is more interesting?

This is a matter of personal opinion. If you are the type of person who likes to know exactly how and why something happens, then theoretical astronomy will appeal to you.

Equations used to model a star

If you like to discover new objects and beautiful sights, then you will most likely have more interest in observational astronomy. Observational astronomers take all of the photos of beautiful galaxies and nebula. Below you can see some of the most beautiful images taken by Hubble.

This new Hubble image, captured and released to celebrate the telescope’s 23rd year in orbit, shows part of the sky in the constellation of Orion (The Hunter). Rising like a giant seahorse from turbulent waves of dust and gas is the Horsehead Nebula, otherwise known as Barnard 33. This image shows the region in infrared light, which has longer wavelengths than visible light and can pierce through the dusty material that usually obscures the nebula’s inner regions. The result is a rather ethereal and fragile-looking structure, made of delicate folds of gas — very different to the nebula’s appearance in visible light.
NASA/ESA Hubble Space Telescope has trained its razor-sharp eye on one of the universe's most stately and photogenic galaxies, the Sombrero galaxy, Messier 104 (M104). The galaxy's hallmark is a brilliant white, bulbous core encircled by the thick dust lanes comprising the spiral structure of the galaxy. As seen from Earth, the galaxy is tilted nearly edge-on. We view it from just six degrees north of its equatorial plane. This brilliant galaxy was named the Sombrero because of its resemblance to the broad rim and high-topped Mexican hat. At a relatively bright magnitude of +8, M104 is just beyond the limit of naked-eye visibility and is easily seen through small telescopes. The Sombrero lies at the southern edge of the rich Virgo cluster of galaxies and is one of the most massive objects in that group, equivalent to 800 billion suns. The galaxy is 50,000 light-years across and is located 30 million light-years from Earth.
The star-forming region NGC 3603 - seen here in the latest Hubble Space Telescope image - contains one of the most impressive massive young star clusters in the Milky Way. Bathed in gas and dust the cluster formed in a huge rush of star formation thought to have occurred around a million years ago. The hot blue stars at the core are responsible for carving out a huge cavity in the gas seen to the right of the star cluster in NGC 3603's centre.
This image of a pair of interacting galaxies called Arp 273 was released to celebrate the 21st anniversary of the launch of the NASA/ESA Hubble Space Telescope. The distorted shape of the larger of the two galaxies shows signs of tidal interactions with the smaller of the two. It is thought that the smaller galaxy has actually passed through the larger one.
o celebrate its 28th anniversary in space the NASA/ESA Hubble Space Telescope took this amazing and colourful image of the Lagoon Nebula. The whole nebula, about 4000 light-years away, is an incredible 55 light-years wide and 20 light-years tall. This image shows only a small part of this turbulent star-formation region, about four light-years across. This stunning nebula was first catalogued in 1654 by the Italian astronomer Giovanni Battista Hodierna, who sought to record nebulous objects in the night sky so they would not be mistaken for comets. Since Hodierna’s observations, the Lagoon Nebula has been photographed and analysed by many telescopes and astronomers all over the world. The observations were taken by Hubble’s Wide Field Camera 3 between 12 February and 18 February 2018.

Do you have a preference for observational or theoretical astronomy? Let me know in the comments below!

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