The mysteries of the universe: What do astronomers do?

The other day I stumbled across a question on twitter. “How do astronomers know all of this”, in response to a post showing the scale of the universe and different objects within it. I replied with a simple explanation about how we use large telescopes to observe various objects and simulations to understand the physics, but I thought I would write a longer blog post on this topic. With the South African government investing heavily on some of these large telescopes, it is even more important for people to understand why this undertaking is so important.

There are two main types of astronomers or astrophysicists. On the one side the theoreticians: the ones that mainly work through complicated mathematical equations and creating mind-blowing simulations; but what I am going to talk about here is observational astrophysics, which I focus on, and where South Africa has shown great interest with the development of the Square Kilometer Array and the successful Southern African Large Telescope.

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Image of spiral galaxy M101 in four X-ray, Optical, Ultraviolet and Infrared Light taken using different telescopes

What exactly do we do?

Observational astronomers use telescopes (like MeerKAT, the Southern African Large Telescope, and several others) to study the night sky. These telescopes function as “light buckets” and collect information in the form of optical (visual) or radio light. Most land-based telescopes operate in optical or radio light because the atmosphere prevents any other light from reaching the earth, but space-based telescopes (like the famous Hubble Space Telescope) can detect X-rays, Infrared, and ultraviolet light.

This light can be used in a few different ways. We can take a picture of distant objects like galaxies to study things like their shape, structure, size and position. We can track how the light in an object like a star changes with time – which is how planets around distant stars are often discovered. Or, we can break the light up into a spectrum, which allows us to probe deeper into the chemical makeup of an object. Different types of light reveal different aspects of astronomical objects. While optical light is really good at detecting stars, the faint gas that fuels galaxies is only visible in radio wavelengths and hot, energetic events pop up as X-rays or gamma rays.

Bigger telescopes allow us to observe objects that are fainter and further away. This allows us to see further back in time, to understand the universe at earlier stages of its evolution. The further away an object is (and often the fainter an object is), the longer it takes for light to reach us here on Earth. Therefore, the light we collect with our telescopes essentially lets us look back in time to when the universe was much younger and smaller than it is today.   

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MeerKAT telescope dishes. Credit: SARAO.

Why does this matter?

Aside from being able to detect asteroids that might crash into Earth, astronomy has many benefits. Studying objects in space allows us to work on answers to some of the mysteries of physics. Gravity – something we all interact with on a daily basis (unless you are reading this from the International Space Station) – is something physicists thought we understood since Isaac Newton’s days. Until some astronomers looked at the motions of galaxies and realised that there was something invisible causing these galaxies to move in unexpected ways. This led to the discovery of dark matter – which we are still trying to figure out!

Just two years ago, the groundbreaking observation of a neutron star merger (which our very own SALT contributed to) revealed where heavy elements like gold are originally created. This event, which was detected through gravitational waves and various wavelengths of light simultaneously, was one of the most important discoveries of this decade.

Astronomy teaches us about how the universe works. Although not every discovery will have implications for our everyday life, we have a natural curiosity about the universe we live. Many people experience a sense of appreciation and wonder when they look up at the night sky, especially in the absence of city lights, and wonder what’s out there. Astronomy allows us to explore that curiosity and appreciate our universe.

(At the very least, astronomy gives us a bountiful amount of pretty pictures. You can find a new one every day on the Astronomy Picture of the Day website.)

If you are curious to learn more about how specific fields in astronomy contribute to scientific questions, I have a post on Medium that goes into much more detail! You can also learn more about astronomy through Crash Course: Astronomy and by following NASA on social media.

10 Things to do to prepare for your studies

Since many of us are getting back to our courses and research, I thought I’d share 10 things that I believe will help me to prepare for my Masters. These are things that will help you save time, stay organized, focus on what’s important for your research and feel more confident. While my experience is limited to being a Masters student in Astrophysics, many of these tips are broadly applicable.

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A research notebook is a place to dump all your thoughts, questions, to-do lists, calculations, meeting notes and general research. I personally love pen and paper, and I’m partial to dot-grid notebooks, but any notebook or even a digital Google Doc could serve this purpose. Having a notebook dedicated for your rough work is so much easier than having dozens of loose sheets of paper that get lost. Because there’s no pressure for this notebook to be any form of neat, it’s easier to make productive mistakes in it.

Listing (academic) strengths and weaknesses

Your Masters studies are the perfect opportunity to improve on your weaknesses and take advantage of your strengths. While there are some things that I am ‘good at’ (like reading and understanding journal articles), there are several other skills in my field that could use some work (like radio astronomy, for example). Knowing what your strengths and weaknesses are can help you find a balance between the stress you can handle, the areas you would like to grow and the intensity of your work.

Deciding on research interests

At Masters level, the academic research world is your oyster. You might want to veer off into something totally new; you might want to stay where you are because of how interesting it is, or where it looks like your field is going. For example, I love extragalactic astronomy so I’m staying right here. However, I might incorporate some relevant techniques from other areas. Since MeerKAT is taking its first data, and the SKA continues to develop, getting more experience with radio observations is vital for me as a South African astronomer.

Choosing a supervisor

Your choice of a supervisor can dictate whether you thrive or survive through postgraduate studies. The best advice I ever got about research was “Choose your supervisor – not your project”. I would suggest meeting with several potential supervisors within your research interests and going with the person you feel like you can comfortably work with. Then develop a project you are interested in together. 

Brainstorming a topic

I haven’t done this (yet) but it is high up on my agenda. After choosing your supervisor, spend a meeting with them brainstorming a few possible ideas for your research project. After this meeting, you can follow up by reading research articles and thinking about what resources you have available (in terms of data, equipment, etc). Although your topic will naturally evolve and change over time, it’s good to have an idea of where to start and where you’d like to be heading.

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My Masters’ programme requires 6 months of coursework and I have to – of course – choose my courses. One of the easiest ways to do this is to talk to students who have done the programme already and are in the same field to find out which courses are most relevant and which ones are not that great. Take your skills, strengths and weaknesses into account to choose courses that will have the most benefit!

Choosing a system to stay organized

As I mentioned in the first point, my notebook is really important for keeping my thoughts organized. However, I will need a system that can handle scheduling and the digital components of my academic life. Since we are in 2019, there are thousands of apps and programmes that make it a lot easier to keep track of papers, references, notes, meetings and classes. Choose a system you like, that is accessible to your devices, and most importantly – works for you (I will be using Google Calendar, Google Docs and my bullet journal for this).

Creating templates

A recent problem I have had is trying to create figures that are all the same size, with readable fonts and colour schemes, that work within A4 journal-article layouts. It’s awful and time-consuming to be fiddling around with plotting parameters and googling fixes for ‘how to make my errorbars thicker in Python’. To solve this, I am going to create templates that I can easily copy and adapt.

Having templates ready will ensure that your work is presented in a consistent way and will save you a lot of time. I will be creating templates for plots, presentations and my actual thesis draft (if you don’t use LaTeX – I would suggest learning it as soon as possible!). Github is a good place to store these templates, and you can have a look at websites like Overleaf for example templates of several types of academic documents.

Updating my CV & LinkedIn account

By the time this post is live, I will be able to officially add ‘MSc Student: Astrophysics & Space Science’ to my CV. It is always good to check if there is anything new that might be missing from your CV and LinkedIn accounts. You never know when there may be a conference, workshop or summer school that you want to apply for on short notice. Having your CV ready to go can save you a lot of stress in these situations.

Reading relevant books

WhatsApp Image 2019-02-20 at 20.30.48.jpegI don’t know about you, but I don’t how to write a thesis. Fortunately, I was recommended a book called ‘How to Succeed in Your Masters and Doctoral Studies’ by Johann Mouton that can (hopefully) teach me. Most university libraries will have a copy of this book or something similar. Have a look around, ask other students for recommendations and try to find a book that appeals to you!

If you are not much of a reader, there may be workshops that you can sign up for offered by your university. Learning how to write a thesis is not something that we’re typically taught in the way Calculus or Statistics are taught and there’s no harm in getting some help!


Even if you’ve done just a few of these things, you’ll feel much more prepared and ready to tackle anything that comes your way this year! All the best for 2019’s academic year.