From the Karoo to the stars
South Africa is a real player on the global astronomy stage
The announcement by NASA in February this year that it has discovered seven Earth-like planets — about the size of our own home — orbiting a star just 40 lightyears away has caused widespread excitement in the world of astronomy.
Since the first discovery of an exoplanet in 1988, interest in the search for extra-terrestrial life has intensified. Mankind has always had a relationship with our galaxy and a fascination with other forms of life that may be out there — and these seven planets and the star they orbit have potential to be suitable for life.
The exoplanets orbit a star in the constellation Aquarius called Trappist-1 — the centre of a solar system very different from our own. Because Trappist-1 is tiny, it is an ultra-cool dwarf star with low mass that allows its planets to orbit closely and remain in the habitable zone. It is about a tenth of the mass of our sun and about one-thousandth as bright.
Interest in exploring the universe and exoplanets is what makes new developments such as the Square Kilometre Array (SKA), a multi-billion dollar international project to build the world’s largest radio telescope, a boon to scientific research.
The SKA will be a collection of hundreds of thousands of radio antennas with a combined collecting area equivalent to approximately one million square metres, or one square kilometre.
Radio astronomy involves the study of the universe through the radio range of the electromagnetic spectrum, between 3kHz and 300GHz — wavelengths of radiation longer than the visible range that our eyes can sense. Many objects in the universe emit radio frequencies, including planets, stars, galaxies, black holes and remnants of the Big Bang.
Unlike higher frequency radiation, radio waves can pass through clouds of dust and gas, including Earth’s atmosphere, making them easily detectable using Earth-based telescopes. Radio astronomy has produced some of history’s greatest astronomical discoveries.
The project is one of the largest scientific endeavours in history and will be more than 10 times more sensitive than any current radio telescope, and much faster at surveying galaxies. The unprecedented flow of data from the telescope will be supported by supercomputing facilities with several times the processing speed of any current supercomputer and one trillion times the computing power that landed men on the Moon.
The SKA project has been in progress since 1993, when the Large Telescope Working Group was established by the International Union of Radio Science, developing objectives for the forthcoming generation of radio astronomy. In 2012 the SKA host sites were selected. Australia’s Murchison region was awarded the low-frequency and survey components and South Africa’s Karoo region was granted the mid- and high-frequency components.
Last year prototype systems were deployed and a critical design review conducted, which led to SKA phase one approval, with construction to happen in 2018 and early science results expected at the beginning of the next decade.
The SKA aims to shed light on longstanding mysteries of the universe, including the question of how the first stars, galaxies and black holes were formed. Using its incredible sensitivity, the SKA will look back 13-billion years to the point of the universe’s infancy, when the opaque plasma created by the Big Bang recombined to form the first neutral particles, which collapsed into the first stars and galaxies.
It will also question the accuracy of Einstein’s Theory of Relativity, and look into differentiating dark matter and dark energy, what drives cosmetic magnetic fields, as well as the all-important question to the person in the street — are we are alone in the universe?
The argument for astronomy
Astronomy tests the fundamental theories around which technology is based and enables the study of scales of size, mass, distance, temperature and density. It also enables the testing of time scales that are impossible to reproduce in a laboratory.
Until the advert of atomic clocks in 1967, astronomy provided the fundamental standard of time, and today astronomical techniques are needed to determine the orientation of the earth in space, which is necessary for the use of Global Positioning Systems (GPS).
From the centuries when man first started to travel, celestial navigation was the only way ships and supply trains were able to find their way. The basics of celestial navigation are still taught in some countries to pilots and seamen for finding their bearings in emergencies.
Astronomy has also impacted on medical advances and many people involved in forensics and medical imaging train as astronomers to learn basic techniques and their application. The career opportunities that stem from studying astronomy are varied and fascinating.