Mysteries of the Universe

How much of our universe do we know?

Public science engagements have been the fuel that drives my love for astronomy. Whenever I have astronomy-related public engagements these are some of the questions I often get: Is there life out there? What is the fate of our universe? How was the universe formed? In this blog, I am to tackle these questions and give a brief overview of the universe as we know it.

The longest presiding theory of how the universe formed is The Big Bang Theory (no Sheldon is not part of it); According to this theory, 13.8 billion years ago the universe was just a single point (singularity) an explosion occurred (‘big bang’) and the universe started expanding. This period of rapid expansion (inflation) lasted for a short moment, as the expansion slowed down the temperature decreased to a point where basic building blocks of particles started forming (nucleosynthesis). This epoch was followed by a phase where the universe was a dense plasma (Cosmic Microwave Background) the remnants of this plasma are still visible today and can be observed using radio telescopes (e.g. ACT; PLANCK). As the universe continued expanding clumps of matter were pulled by gravity and stars were birthed. As more matter accreted larger structures started forming; first galaxies, then clusters of galaxies and these structure formations evolved to the universe we have today.

Source: phys.org

The Lambda Cold Dark Matter (LCDM) model is the mathematical representation of the Big Bang theory. Lambda (Λ) is the cosmological constant which was used by Einstein to compute his theory of general relativity; it is related to dark energy (which could be understood as a force that pulls things apart, causing the universe to expand). Cold dark matter is deferent to the normal matter (baryonic) as it does not emit light (‘photons’) but its existence is proved through its gravitational effects. According to this model, the universe is constituted of 68% dark energy, 27% dark matter and 5% ‘normal’ matter. So, all the stars you see at night and the billions of galaxies that have been observed only make up 5% of the universe! Using the LCDM model we can also predict the fate of our universe; currently, cosmologists believe that our universe is ‘flat’, hence, it will continue expanding forever and eventually the universe will be a cold frozen place. No need to worry though, it won’t happen any time soon (soon being billion years scale).

Although the Big Bang theory and the LCDM model explain the bulk of the observable universe, it has been adapted to further explain the physical phenomenon that we observe today (e.g. The Oscillating Universe Theory).

The curious mind never rests! So now that we have a clearer idea of the origins of the universe more questions pop up. One of the prominent questions is: Are we alone in the universe? I believe not, but of course, we have to back our beliefs with scientific evidence. There are two main approaches to answering this question; searching for earth-like planets and awaiting signals from aliens.

Kepler, a NASA space telescope is on a mission to locate planets that are in the habitable zone which could sustain life. To date, Kepler has detected 4164 exoplanets and recently it was reported that the most earth-like planet was discovered by the Kepler mission. This exoplanet orbits a star similar to our sun, it’s 1.06 times bigger and receives 75% of the sunlight that Earth receives from the sun. As exciting as it may sound, this planet is 300 light-years away from us; this means that if we were able to travel at the speed of light, it would take us 300 years to reach this planet. So please take care of our planet, we have no alternative home!

The SETI Institute, on the other hand, aims to use radio telescopes to ‘listen’ to extraterrestrial intelligent life. Their strategy is to search for narrow-band radio transmissions that come from outside our solar system, these transmissions would indicate extraterrestrial technological advancement and signal the possibility of intelligent life outside our solar system. A SETI Institute researcher once presented at a conference I was attending, a student asked: ‘So if we do eventually find aliens, what’s the plan?’. The presenter didn’t quite answer the question, my only hope is that they would be kinder than humans.

Astronomy is an exciting field because it is continuously evolving. With the majority of the Square Kilometre Array (SKA) being hosted by South Africa, there has never been a better time for young students to hop on the astronomy bandwagon. The SKA project will require expertise from various fields such as; Engineering, Artisan, Computer Science etc. The beauty of astronomy is that it doesn’t box one to a particular set of skills but instead exposes one to various fields.

The ultimate ‘cherry on top’ is that although many questions have been answered, many more are yet to be asked. Sometimes it takes decades to answer one question (e.g. the existence of gravitational waves) and at times the discovery of one phenomenon raises a thousand more questions (e.g. Fast Radio Bursts). So if you, like me, are always on a quest for problems to solve; then astronomy will be equally fascinating for you.

From MeerKAT to beyond the Milky Way

South Africa is a very exciting place to do astronomy for many reasons. The most prominent reason? The MeerKAT telescope. In this post, I’m (finally) going to write about the most talked-about telescope on the African continent and why I’m so excited about it! I’ll tell you about the telescope, my involvement in it and why it’s so groundbreaking. 

MeerKAT_Radio_Telescope

What is MeerKAT?

In technical terms, MeerKAT is a 64-dish radio interferometer telescope and is the precursor to the Square Kilometer Array telescope. MeerKAT receives astronomical signals across its 64 dishes, which provides an extremely high level of sensitivity. These signals come in the form of radio waves – the same kind of radio waves that you use to listen to 5FM, make cellphone calls with and connect to the WiFi over. Since radio waves are commonly used all over the world for everyday tasks, detecting them from space is particularly challenging. This is why the Karoo was chosen as the location for MeerKAT and subsequently SKA. It’s far from most cities and people, in a special ‘radio-quiet’ zone. With very little radio interference in the area and the high sensitivity that comes with 64 radio dishes, MeerKAT is able to detect extremely faint signals from the distant universe right here in South Africa!

My MeerKAT work 

Although I’m not directly involved in MeerKAT through the South African Radio Astronomical Observatory or using radio observations, my Masters research is part of one of the ‘Large Survey Projects’ that are in-progress. The project – called LADUMA (Looking At the Distant Universe with the MeerKAT Array) – will measure faint, neutral hydrogen gas far back in the universe’s history. Although this gas is very difficult to detect, it’s the most abundant element in the universe and fuels the birth of stars. 

Why am I so excited about this?

MeerKAT has – and will continue to – produced amazing science and it’s only a year old! It has already produced two papers published in Nature (most excitingly – the discovery of giant, radio bubbles at the center of the Milky Way) and its sensitivity has exceeded expectations. The technical upgrades and new modes that are still in development and are being added to the telescope will continue to improve its effectiveness and unlock new kinds of science.

Aside from the science – MeerKAT is South African! Unlike Table Mountain and the Kruger National Park and several other things that we’re proud of as South Africans – MeerKAT is something that we’ve built. When I was growing up, telescopes like the SKA, MeerKAT and SALT were a source of inspiration and interest for me as a future scientist. Now, it’s incredible to be part of these big projects. 

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MeerKAT has also created so many opportunities for South Africans to study and train as astronomers, engineers, computer scientists, and develop expertise in many different areas. Although many people work in astronomy and astronomy-related fields, a large portion of people take these skills to other fields that contribute to the country.

Overall, MeerKAT is proof that South Africa can be at the forefront of science and technology. It’s a massive undertaking that we’ve not only succeeded at – but excelled at. When there are so many other problems that we’re facing as a country – it’s a source of hope and a sign of progress. The future of science in South Africa is bright.