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.”
Auto rivals team up for connected car demo
Rivals BMW, Ford and Groupe PSA, maker of Peugeot and Opel cars, have teamed up with the 5G Automotive Association (5GAA), Qualcomm Technologies and Savari for Europe’s first live demonstration of C-V2X direct communication technology operating across vehicles from multiple auto manufacturers.
The live demonstration also featured a live showcase of C-V2X direct communication technology operating between passenger cars, motorcycles, and roadside infrastructure. C-V2X is a global solution for vehicle-to-everything (V2X) communication in support of improved automotive safety, automated driving and traffic efficiency.
The demonstration exhibited the road safety and traffic efficiency benefits of using C-V2X for Vehicle-to-Vehicle (V2V) collision avoidance, as well as Vehicle-to-Infrastructure (V2I) connectivity to traffic signals and Traffic Management Centers (TMC). C-V2X was operated using real-time direct communications over ITS spectrum and demonstrated its ability to work without cellular network coverage, and underscores its commercial readiness for industry deployment as early as 2020. Superior performance and cost-effectiveness compared to other V2X technologies, along with forward-compatibility with 5G, make C-V2X direct communications a preferred solution for C-ITS applications.
Six demonstrations were shown including: Emergency Electronic Brake Light, Intersection Collision Warning, Across Traffic Turn Collision Risk Warning, Slow Vehicle Warning and Stationary Vehicle Warning, Signal Phase and Timing / Signal Violation Warning and Vulnerable Road User (pedestrian) Warning. The vehicles involved included two-wheel e-scooters provided by BMW Group, and automotive passenger vehicles provided by Ford, Groupe PSA, and BMW Group, all of which were equipped with C-V2X direct communication technology using the Qualcomm® 9150 C-V2X chipset solution. V2X software stack and application software, along with roadside infrastructure, were provided by industry leader, Savari.
C-V2X is globally supported by a broad automotive ecosystem, which includes the fast growing 5GAA organization. The 5GAA involves over 85 global members comprised of many leading automakers, Tier-1 suppliers, software developers, mobile operators, semiconductor companies, test equipment vendors, telecom suppliers, traffic signal suppliers and road operators.
Cellular modems will be key to the C-V2X deployment in vehicles to support telematics, eCall, connected infotainment and delivering useful driving/traffic/parking information. As C-V2X direct communication functionality is integrated into the cellular modem, C-V2X solutions are expected to be more cost-efficient and economical over competing technologies, and benefit from accelerated attach rates. C-V2X direct communication field validations are currently underway in Germany, France, Korea, China, Japan and the U.S.
C-V2X currently stands as the only V2X technology based on globally recognized 3rd Generation Partnership Project (3GPP) specifications, with ongoing evolution designed to offer forward compatibility with 5G. C-V2X also leverages and reuses the upper layer protocols defined by the automotive industry, including the European Telecommunications Standards Institute (ETSI) organization. C-V2X includes two complementary transmission modes:
- Direct communication as shown in this demonstration for V2V and V2I use cases
- V2N network communication, which leverages mobile operators for connectivity and delivers cloud-based services, including automated crash notification (ACN, as mandated by eCall), hazard warnings, weather conditions, green light optimal speed advisory (GLOSA), parking spot location, and remote tele-operation to support automated driving, to name a few.
“This demonstration builds on the successful C-V2X showcase we organised with our members Audi, Ford and Qualcomm in Washington DC in April, said Christoph Voigt, Chairman of 5GAA.
“We are excited to witness the growing momentum behind this life-saving technology and to see our members working together to deploy C-V2X, and to make it hit the road as soon as possible.”
“The BMW Group introduced the first C-ITS use cases already in 2013 with the market introduction of the BMW i3. Today most of envisaged C-ITS use-cases are already institutionalized. With the implementation of C-V2X, the BMW Group accomplishes the last set of the puzzle with a practical path to C-ITS showing quick benefits,” said Christoph Grote, Senior Vice President Electronics, BMW Group.
“With its ability to safely and securely connect vehicles, along with its evolution into 5G, C-V2X is integral to Ford’s vision for future transportation in which all cars and infrastructure talk to each other,” said Thomas Lukaszewicz, Manager Automated Driving, Ford of Europe. “We are very encouraged by preliminary test results in Europe and elsewhere which support our belief that C-V2X direct communications has superior V2X communication capabilities.”
“We’re moving forward with seamless communication between cars and their environment for enhancing road safety, as well as our customers’ safety,” said Carla Gohin, Group PSA’s Vice President for Research and Advanced Engineering. “Following the first European C-V2X direct communications demonstration we hosted with Qualcomm Technologies last March, we’re pleased to work with leading automotive and technology companies today to highlight that C-V2X interoperability is a reality.”
“This demonstration of interoperability between multiple automakers is not only another milestone achieved towards C-V2X deployment, but also further validates the commercial viability and global compatibility of C-V2X direct communications for connected vehicles,” said Enrico Salvatori, senior vice president & president, Qualcomm Europe and MEA. “We look forward in continuing to work alongside leaders in the automotive industry, like the 5GAA, BMW Group, Ford, Groupe PSA and Savari, to help advance the automotive industry’s shift towards a safer, connected and more autonomous future.”
“As one of the V2X pioneers, our company is extremely pleased to continue to help enable the next step in the V2X revolution that we helped start back in 2008,” said Ravi Puvvala, CEO of Savari. “For the last year and a half, the Savari team has worked diligently alongside the dedicated C-V2X engineers in the 5GAA partnership. The resulting string of increasingly impressive demonstrations is continuing to convince the world that C-V2X will soon be deployed around the world.”
Win a Poster Heater with Gadget and Takealot.com
This winter Gadget and Takealot.com are giving away three Poster Heaters, which look like posters but become heaters when you plug them in.
Three Gadget readers will each win a unit, valued at R550 each. To enter, follow @GadgetZA and @Takealot on Twitter and tell us on the @GadgetZA account how many Watts the heater consumes.
What’s the big deal about these heaters? Many of us are struggling to keep the balance between soaring electricity costs and the need to keep warm this winter.
However, the recently launched Poster Heater by EasyHeat and distributed in South Africa by Takealot.com is not only one of the most cost effective electric heaters currently on the market, it is also easy to setup and use.
As the name indicates, it is a poster similar to one you would hang on a wall. But, plug it in and it turns into a 300 Watt heater. The Poster Heater isn’t designed to heat hallways or large rooms, but rather smaller ones like a bedroom or a baby’s nursery or a dressing room.
It uses radiant heating, which means that it heats up in a couple of minutes and the heat is directed at the objects or people around it, quickly taking the chill out of the air and providing a comfortable ambient temperature.
The other advantage of radiant heating is that it doesn’t dry out the air like infrared or gas heaters. Users also don’t have to worry about their children or pets getting too close to it because, even though it gets hot, it can be touched.
To enter the competition follow the steps below:
Competition entry details:
3. The competition closes on 31 July 2018.
4. Winners will be notified via Twitter on 1 August and Takealot.com will be in touch to organise delivery.
5. The competition is only open to South African residents.