A collaboration of telescopes, including a contribution by the Southern African Large Telescope (SALT) in Sutherland, has unveiled a cosmic explosion about 200 times more powerful than a typical supernova.
To prove the record breaking nature of this supernova explosion, crucially, its distance had to be established. This was achieved with spectroscopic observations taken by SALT.
“Upon seeing the spectral signatures from SALT and realising that we had discovered the most powerful supernova yet, I was too excited to sleep the rest of the night,” said Subo Dong, an astronomer and a Youth Qianren Research Professor at the Kavli Institute for Astronomy and Astrophysics (KIAA) at Peking University.
“This impressive result highlights strengths of SALT and the benefits of Chinese-South African collaboration in astronomy, and we are looking forward to strengthening such collaboration in future”, said Petri Vaisanen, head of science operations at SALT.
At its peak intensity the explosion, called ASASSN-15lh, shone with 570 billion times the brightness of the Sun. If that statistic does not impress, consider that this luminosity level is approximately 20 times the entire output of the 100 billion stars comprising our Milky Way galaxy.
As described in a new study published today in Science, ASASSN-15lh is amongst the closest superluminous supernovae ever found, at around 3.8 billion light years away. Given its exceptional brightness and closeness, ASASSN-15lh might offer key clues in unlocking the secrets of this baffling class of celestial detonations.
“ASASSN-15lh is the most powerful supernova discovered in human history,” said Dong, the study lead author. “The explosion’s mechanism and power source remain shrouded in mystery because all known theories meet serious challenges in explaining the immense amount of energy ASASSN-15lh has radiated.”
ASASSN-15lh was first glimpsed in June 2015 by twin telescopes with 14-centimeter diameter lenses in Cerro Tololo, Chile conducting the All Sky Automated Survey for SuperNovae (ASAS-SN), an international collaboration headquartered at The Ohio State University. (Hence ASASSN-15lh’s somewhat menacing moniker.) These two tiny telescopes sweep the skies to detect suddenly appearing objects like ASASSN-15lh that are intrinsically very bright, but are too far away for human observers to notice.
A spectrum taken at the 2.5 meter du Pont telescope in Chile suggested that ASASSN-15lh might indeed be a superluminous supernova.
To know for sure how luminous ASASSN-15lh was, a measurement of its distance was required. This was determined with spectroscopic observations by Dong’s colleague Saurabh Jha of Rutgers University using the Southern African Large Telescope (SALT). “SALT and its queue schedule observing are ideal for rapidly following up transient events like ASASSN-15lh,” explained Jha.
To clear up where exactly ASASSN-15lh is located, as well as numerous other mysteries regarding it and its hyper-kinetic ilk, the research team has been granted valuable time this year on the Hubble Space Telescope. With Hubble, Dong and colleagues will obtain the most detailed views yet of the aftermath of ASASSN-15lh’s stunning explosion. In concert, Jha has continued to use SALT to obtain spectroscopic follow-up observations to analyze the composition and structure of the explosion as it progresses, including making use of special “Director’s discretionary time” awarded to study this unique event. Important insights into the true wellspring of its power should come to light.
One of the best hypotheses is that superluminous supernovae’s stupendous energy comes from highly magnetized, rapidly spinning neutron stars called magnetars, which are the leftover, hyper-compressed cores of massive, exploded stars. But ASASSN-15lh is so luminous that this compelling magnetar scenario falls short of the required energies. Instead, ASASSN-15lh-esque supernovae might be triggered by the demise of incredibly massive stars that go beyond the top tier of masses most astronomers would speculate are even attainable.
“The honest answer is at this point that we do not know what could be the power source for ASASSN-15lh,” said Dong. “ASASSN-15lh may lead to new thinking and new observations of the whole class of superluminous supernova, and we look forward to plenty more of both in the years ahead.”
Money talks and electronic gaming evolves
Computer gaming has evolved dramatically in the last two years, as it follows the money, writes ARTHUR GOLDSTUCK in the second of a two-part series.
The clue that gaming has become big business in South Africa was delivered by a non-gaming brand. When Comic Con, an American popular culture convention that has become a mecca for comics enthusiasts, was hosted in South Arica for the first time last month, it used gaming as the major drawcard. More than 45 000 people attended.
The event and its attendance was expected to be a major dampener for the annual rAge gaming expo, which took place just weeks later. Instead, rAge saw only a marginal fall in visitor numbers. No less than 34 000 people descended on the Ticketpro Dome for the chaos of cosplay, LAN gaming, virtual reality, board gaming and new video games.
It proved not only that there was room for more than one major gaming event, but also that a massive market exists for the sector in South Africa. And with a large market, one also found numerous gaming niches that either emerged afresh or will keep going over the years. One of these, LAN (for Local Area Network) gaming, which sees hordes of players camping out at the venue for three days to play each other on elaborate computer rigs, was back as strong as ever at rAge.
MWeb provided an 8Gbps line to the expo, to connect all these gamers, and recorded 120TB in downloads and 15Tb in uploads – a total that would have used up the entire country’s bandwidth a few years ago.
“LANs are supposed to be a thing of the past, yet we buck the trend each year,” says Michael James, senior project manager and owner of rAge. “It is more of a spectacle than a simple LAN, so I can understand.”
New phenomena, often associated with the flavour of the moment, also emerge every year.
“Fortnite is a good example this year of how we evolve,” says James. “It’s a crazy huge phenomenon and nobody was servicing the demand from a tournament point of view. So rAge and Xbox created a casual LAN tournament that anyone could enter and win a prize. I think the top 10 people got something each round.”
Read on to see how esports is starting to make an impact in gaming.
Blockchain is generally associated with Bitcoin and other cryptocurrencies, but these are just the tip of the iceberg, says ESET Southern Africa.
This technology was originally conceived in 1991, when Stuart Haber and W. Scott Stornetta described their first work on a chain of cryptographically secured blocks, but only gained notoriety in 2008, when it became popular with the arrival of Bitcoin. It is currently gaining demand in other commercial applications and its annual growth is expected to reach 51% by 2022 in numerous markets, such as those of financial institutions and the Internet of Things (IoT), according to MarketWatch.
What is blockchain?
A blockchain is a unique, consensual record that is distributed over multiple network nodes. In the case of cryptocurrencies, think of it as the accounting ledger where each transaction is recorded.
A blockchain transaction is complex and can be difficult to understand if you delve into the inner details of how it works, but the basic idea is simple to follow.
Each block stores:
– A number of valid records or transactions.
– Information referring to that block.
– A link to the previous block and next block through the hash of each block—a unique code that can be thought of as the block’s fingerprint.
Accordingly, each block has a specific and immovable place within the chain, since each block contains information from the hash of the previous block. The entire chain is stored in each network node that makes up the blockchain, so an exact copy of the chain is stored in all network participants.
As new records are created, they are first verified and validated by the network nodes and then added to a new block that is linked to the chain.
How is blockchain so secure?
Being a distributed technology in which each network node stores an exact copy of the chain, the availability of the information is guaranteed at all times. So if an attacker wanted to cause a denial-of-service attack, they would have to annul all network nodes since it only takes one node to be operative for the information to be available.
Besides that, since each record is consensual, and all nodes contain the same information, it is almost impossible to alter it, ensuring its integrity. If an attacker wanted to modify the information in a blockchain, they would have to modify the entire chain in at least 51% of the nodes.
In blockchain, data is distributed across all network nodes. With no central node, all participate equally, storing, and validating all information. It is a very powerful tool for transmitting and storing information in a reliable way; a decentralised model in which the information belongs to us, since we do not need a company to provide the service.
What else can blockchain be used for?
Essentially, blockchain can be used to store any type of information that must be kept intact and remain available in a secure, decentralised and cheaper way than through intermediaries. Moreover, since the information stored is encrypted, its confidentiality can be guaranteed, as only those who have the encryption key can access it.
Use of blockchain in healthcare
Health records could be consolidated and stored in blockchain, for instance. This would mean that the medical history of each patient would be safe and, at the same time, available to each doctor authorised, regardless of the health centre where the patient was treated. Even the pharmaceutical industry could use this technology to verify medicines and prevent counterfeiting.
Use of blockchain for documents
Blockchain would also be very useful for managing digital assets and documentation. Up to now, the problem with digital is that everything is easy to copy, but Blockchain allows you to record purchases, deeds, documents, or any other type of online asset without them being falsified.
Other blockchain uses
This technology could also revolutionise the Internet of Things (IoT) market where the challenge lies in the millions of devices connected to the internet that must be managed by the supplier companies. In a few years’ time, the centralised model won’t be able to support so many devices, not to mention the fact that many of these are not secure enough. With blockchain, devices can communicate through the network directly, safely, and reliably with no need for intermediaries.
Blockchain allows you to verify, validate, track, and store all types of information, from digital certificates, democratic voting systems, logistics and messaging services, to intelligent contracts and, of course, money and financial transactions.
Without doubt, blockchain has turned the immutable and decentralized layer the internet has always dreamed about into a reality. This technology takes reliance out of the equation and replaces it with mathematical fact.