The South African Astronomical Observatory and the Southern African Large Telescope are among the 70 ground- and space-based observatories that observed the explosion of two colliding neutron stars, immediately after their gravitational shock waves were detected by the U.S.-based Laser Interferometer Gravitational-Wave Observatory.
Neutron stars are the smallest, densest stars known. They are the remains of massive stars which exploded as supernovae. In this particular event, dubbed GW170817, two such neutron stars spiralled inwards and then collided, emitting gravitational waves that were detectable for about 100 seconds. The collision also resulted in a kilonova explosion of light, initially in the form of gamma rays which were detected by space-based telescopes. The gamma rays were then followed by X-rays, ultraviolet, optical, infrared, and radio waves.
This allowed astronomers to localise the event within hours and launch follow-up observations by SALT and numerous other telescopes in South Africa and around the world. South African activities also included the first observations contributing to published scientific results by the MeerKAT radio telescope under construction in the Karoo.
Gravitational waves from colliding black holes were first detected only two years ago, and have been detected three more times since then, leading to the 2017 Nobel Prize in Physics being awarded to three US scientists. Black hole collisions, however, are not expected to emit light. GW170817 is the first time light and gravitational waves from the same event have been observed.
The significance of the present event lies in the combination of the gravitational waves and light. “Imagine you have only one sense”, explains Petri Vaisanen, Head of SALT Astronomy Operations, who was the observer at SALT during the frantic search for the counterpart for the gravitational wave event. “All your life you have merely looked at the world. Two years ago you heard something, voices coming from somewhere around you. But then, suddenly, you actually see someone talking. How much more will you understand about how the world works when you put those together? Immensely more. That to me sums up the momentous discovery, and hints at the possibilities going forward.”
August 18, 2017, the day and night following the LIGO detection and the initial successful searches in Chile for the counterpart, was a busy day for observational astronomers. “After a flurry of messages and emails that afternoon in Sutherland, I finally got the coordinates”, continues Vaisanen. “There was a new object, which had caused the whole of space-time to ripple, sitting at the outskirts of the galaxy NGC 4993 some 130 million light-years away. I knew that everyone with a working telescope in the Southern Hemisphere was scrambling to get data on it. We decided to drop all other plans for that evening, and went for a spectral observation with SALT, since you need a large telescope for such observations breaking up the light into all its colours. It was a difficult observation since we had to do it in twilight, before it got properly dark. I’m very proud of the whole team, SALT was only the third observatory to provide a spectrum of the target, and the first spectrum that clearly started showing anomalous behaviour proving that this was no run-of-the-mill transient event”.
The significance of getting early observations stems from the afterglow of the collision changing very rapidly. Piecing together the new science from the event requires combining observations spanning the first hours, days and weeks after the merger. The first SALT spectrum has a very prestigious spot in the combined scientific paper, with thousands of authors and hundreds of institutions. In addition, several, more detailed scientific papers have also been written based on SALT, SAAO and other Sutherland observations.
“Finally, the irony of the moment for me, anxiously sitting at the telescope that evening looking at the new object, was that just three weeks before I had attended a meeting discussing the future of optical searches of gravitational waves and the SAAO part in it. There were arguments that it could be decades before we are able to localise such events well enough for observations, and it would probably not be worth expending the effort. It’s amazing how quickly things change.”
Sutherland telescopes reveal the details of the neutron star merger
Theorists have predicted that what follows the initial collision is a “kilonova” explosion— a phenomenon by which the material that is left over from the neutron star collision, which glows with light, is blown out of the immediate region, far out into space. The light-based observations from other large international telescopes show that heavy elements, such as lead and gold, are created in these collisions and subsequently distributed throughout the universe – confirming the theory that a major source for the creation of elements heavier than iron does, indeed, results from these neutron star mergers.
The early SALT observations showed that the explosion was relatively bright and blue. Only two or three days later, further observations by SALT, SAAO and other major international telescopes showed that the light was rapidly fading and turning red, due to the dusty debris blocking the bluer light, as predicted by the theory of the evolution of a kilonova explosion. Simultaneously, MASTER (a joint Russian-South African optical telescope located in Sutherland) and IRSF (Infra-Red Survey Facility; a joint Japanese-South African infrared telescope also in Sutherland) continued to monitor GW170817 for two weeks, showing that it gradually faded in the visible light but brightened in the infrared, consistent with the final stages of the afterglow from the surrounding debris.
The results of this unprecedented event have demonstrated the importance of collaborative multi-messenger observations and mark a new era in astronomy. “The ability of SALT and SAAO telescopes to respond rapidly to unexpected discoveries is a major reason for the success of these observations and will ensure similar successes in the future”, says Dr Stephen Potter, Head of Astronomy at the SAAO. “We are very proud to have played a major role in such a historical event thanks to the sterling efforts and expertise of SAAO and SALT staff who ensure that our observatory is at the forefront of world-class scientific endeavours.”
Online retail gets real
After decades of experience in selling online, retailers still seek out the secret of reaching the digital consumer, writes ARTHUR GOLDSTUCK.
It’s been 23 years since the first pizza and the first bunch of flowers was sold online. One would think, after all this time, that retailers would know exactly what works, and exactly how the digital consumer thinks.
Yet, in shopping-mad South Africa, only 4% of adults regularly shop online. One could blame high data costs, low levels of tech-savviness, or lack of trust. However, that doesn’t explain why a population where more than a quarter of people have a debit or credit card and almost 40% of people use the Internet is staying away.
The new Online Retail in South Africa 2019 study, conducted by World Wide Worx with the support of Visa and Platinum Seed, reveals that growth is in fact healthy, but is still coming off a low base. This year, the total sale of retail products online is expected to pass the R14-billion mark, making up 1.4% of total retail.
This figure represents 25% growth over 2017, and comes after the same rate of growth was seen in 2017. At this rate, it is clear that online retail is going mainstream, driven by aggressive marketing, and new shopping channels like mobile shopping.
But it is equally clear that not all retailers are getting it right. According to the study, the unwillingness of business to reinvest revenue in developing their online presence is one of the main barriers to long-term success. Only one in five companies surveyed invested more than 20% of their online turnover back into their online store. Over half invested less than 10% back.
On the surface, the industry looks healthy, as a surprisingly high 71% of online retailers surveyed say they are profitable. But this brings to mind the early days of Amazon.com, in 1996, when founder Jeff Bezos was asked when it would become profitable.
He declared that it would not be profitable for at least another five years. And if it did, he said, it would be in big trouble. He meant that it was so important for long-term sustainability that Amazon reinvest all its revenues in customer systems, that it could not afford to look for short-term profits.
According to the South African study, the single most critical factor in the success of online retail activities is customer service. A vast majority, 98% of respondents, regarded it as important. This positions customer service as the very heart of online retail. For Amazon, investment back into systems that would streamline customer service became the key to the world’s digital wallets.
In South Africa online still make up a small proportion of overall retail, but for the first time we see the promise of a broader range of businesses in terms of category, size, turnover and employee numbers. This is a sign that our local market is beginning to mature.
Clothing and apparel is the fastest growing sector, but is also the sector with the highest turnover of businesses. It illustrates the dangers of a low barrier to entry: the survival rate of online stores in this sector is probably directly opposite to the ease of setting up an online apparel store.
A fast-growing category that was fairly low on the agenda in the past, alcohol, tobacco and vaping, has benefited from the increased online supply of vapes, juices and accessories. It also suggests that smoking bans, and the change in the legal status of marijuana during the survey, may have boosted demand.
In the coming weeks, we can expect online retail to fall under the spotlight as never before. Black Friday, a shopping tradition imported “wholesale” from the United States, is expected to become the biggest online shopping day of the year in South Africa, as it is in the USA.
Initially, it was just a gimmick in South Africa, attempting to cash in on what was a purely American tradition of insane sales on the Friday after Thanksgiving Day, which occurs on the third Thursday of November every year. It is followed by Cyber Monday, making the entire weekend one of major promotions and great bargains.
It has grown every year in South Africa since its first introduction about six years ago, and last year it broke into the mainstream, with numerous high profile retailers embracing it, and many consumers experiencing it for the first time.
It is now positioned as the prime bargain day of the year for consumers, and many wait in anticipation for it, as they do in the USA. Along with Cyber Monday, it provides an excuse for retailers to go all out in their marketing, and for consumers to storm the display shelves or web pages. South African shoppers, clearly, are easily enticed by bargains.
Word of mouth around Black Friday has also grown massively in the past two years, driven by both media and shoppers who have found ridiculous bargains. As news spreads that the most ridiculous of the bargains are to be had online, even those who were reticent of digital shopping will be tempted to convert.
The Online Retail in SA 2019 report has shown over the years that, as people become more experienced in using the Internet, their propensity to shop online increases. This is part of the World Wide Worx model known as the Digital Participation Curve. The key missing factor in the Curve is that most retailers do not know how to convert that propensity into actual online shopping behaviour. Black Friday will be one of the keys to conversion.
Carry on reading to find out about the online retailers of the year.
Reliable satellite Internet?
MzansiSat, a satellite-Internet business, aims to beam Internet connections to places in South Africa which don’t have access to cabled and mobile network infrastructure, writes BRYAN TURNER.
Stellenbosch-based MzansiSat promises to provide cheap wholesale Internet to Internet Service Providers for as little as R25 per Gigabyte. Providers who offer more expensive Internet services could benefit greatly from partnering with MzansiSat, says the company.
“Using MzansiSat, we hope that we can carry over cost-savings benefits to the consumer,” says Victor Stephanopoli, MzansiSat chief operating officer.
The company, which has been spun off from StellSat, has been looking to increase its investor portfolio while it waits for spectrum approval. The additional investment will allow MzansiSat’s satellite to operate in more regions across Africa.
The MzansiSat satellite is being built by Thales Alenia Space, a French company which is also acting as technical partner to MzansiSat. In addition to building the satellite, Thales Alenia Space will also be assisting MzansiSat in coordinating the launch. The company intends to launch the satellite into the 56°E orbital slot in a geostationary orbit, which enables communication almost anywhere in Africa. The launch is expected to happen in 2022.
The satellite will have 76 transponders, 48 of which will be Ku-band and 28 C-band. Ku-band is all about high-speed performance, while C-band deals with weather-resistance. The design intention is for customers of MzansiSat to choose between very cheap, reliable data and very fast, power-efficient data.
C-band is an older technology, which makes bandwidth cheaper and almost never affected by rain but requires bigger dishes and slower bandwidth compared to Ku-band connections. On the other hand, Ku-band is faster, experiences less microwave interference, and requires less power to run – but is less reliable with bad weather conditions.
MzansiSat’s potential military applications are significant, due to the nature of the military being mobile and possibly in remote areas without connectivity. Connectivity everywhere would be potentially be life-saving.
Consumers in remote areas will benefit, even though satellite is higher in latency than fibre and LTE connections. While this level of latency is high (a fifth of a second in theory), satellite connections are still adequate for browsing the Internet and watching online content.
The Internet of Things (IoT) may see the benefits of satellite Internet before consumers do. The applications of IoT in agriculture are vast, from hydration sensors to soil nutrient testers, and can be realised with an Internet connection which is available in a remote area.
Stephanopoli says that e-learning in remote areas can also benefit from MzansiSat’s presence, as many school resources are becoming readily available online.
“Through our network, the learning experience can be beamed into classrooms across the country to substitute or complement local resources within the South African schooling system.”