After finding three times more black holes than expected in the Palomar 5 cluster, scientists believe they may have unlocked an understanding of how stellar streams are formed.
In the darkness of space, there are voyages of stars travelling in bright streams.
The origins of these stellar ‘tidal streams’ aren’t fully known, but they are thought to be ejected from disrupted dwarf galaxies or from star clusters.
A new paper published in Nature Astronomy addresses star clusters, black holes and their relation with star streams by examining Palomar 5, a globular cluster.
“We do not know how these streams form, but one idea is that they are disrupted star clusters,” explained Prof Mark Gieles from the Institute of Cosmos Sciences of the University of Barcelona, who is lead author of the paper.
“However, none of the recently discovered streams have a star cluster associated with them, hence we can not be sure. So, to understand how these streams formed, we need to study one with a stellar system associated with it. Palomar 5 is the only case, making it a Rosetta Stone for understanding stream formation.”
The 10bn-year-old cluster Palomar 5 is located about 80,000 light-years away in the Serpens constellation, and is one of roughly 150 globular clusters that orbit around the Milky Way.
Born during the earliest stages of galaxy formation, it is now in its final stages of dissolution. In Palomar 5, the researchers believe that they might have unlocked an understanding of these stellar streams.
Researchers simulated the orbits and the evolution of each star from the formation of the cluster until its final dissolution. They varied the initial properties of the cluster until a good match with observations of the stream and the cluster was found.
While Palomar 5 formed with a lower black hole fraction, they found that stars escaped more efficiently than black holes.
“The number of black holes is roughly three times larger than expected from the number of stars in the cluster, and it means that more than 20pc of the total cluster mass is made up of black holes,” said Gieles.
“They each have a mass of about 20 times the mass of the sun and they formed in supernova explosions at the end of the lives of massive stars, when the cluster was still very young.”
Over time, the black hole fraction began to increase, puffing up the cluster in what researchers called a “gravitational slingshot” interaction. This launched even more stars into the void, creating the star stream.
As more and more stars fly out of the cluster, in approximately a billion years’ time, Palomar 5 will disappear and only black holes will be there at its demise.
“This work has helped us understand that even though the fluffy Palomar 5 cluster has the brightest and longest tails of any cluster in the Milky Way, it is not unique,” added Dr Denis Erkal, a co-author of the paper from the University of Surrey.
“Instead, we believe that many similarly puffed up, black hole-dominated clusters have already disintegrated in the Milky Way tides to form the recently discovered thin stellar streams.”
The researchers highlighted the importance of the work for understanding globular cluster formation, the initial masses of stars and for the evolution of massive stars. What’s more, it has important implications for the study of gravitational waves.
“It is believed that a large fraction of binary black hole mergers form in star clusters,” said Dr Fabio Antonini from Cardiff University, another co-author on the paper.
“A big unknown in this scenario is how many black holes there are in clusters, which is hard to constrain observationally because we cannot see black holes. Our method gives us a way to learn how many [black holes] there are in a star cluster by looking at the stars they eject.”
Qualtrics CEO Zig Serafin sat down with Silicon Republic editor Elaine Burke to discuss his leadership style as an expert in experience management.
It has been an eventful few years for US tech company Qualtrics, and not least because of the pandemic.
The company founded by a family out of Utah was bought by SAP in 2018 for $8bn. It then went public in January 2021 with a successful IPO that valued the company at $15bn. That same year then saw Qualtrics earn $1bn in revenue for its experience management technology. But what is experience management?
CEO Zig Serafin says it’s the “ultimate advantage” for modern businesses. It’s about tuning in to the needs and desires of customers and taking action on that knowledge “with empathy, with speed and at scale”.
Serafin was in Dublin recently while on a tour across Europe meeting with Qualtrics clients. He spoke with SiliconRepublic.com for our Conversations with Leaders series shortly after checking in on the company’s new office in the Irish capital.
Qualtrics’ already substantial footprint a stone’s throw from St Stephen’s Green is expanding in response to the company’s global growth. “Dublin is the epicentre of how we operate across Europe,” said Serafin, and this European HQ is fully equipped with all the fixings of the modern tech office and more – including its own pub.
But Serafin said Qualtrics, a company obsessed with creating optimal experiences, knows that these days workplaces need to offer flexibility and the ability to work from home as well as a workspace that provides a “home from home”.
“Both experiences are important,” he said. “That digital experience and the physical experience, and how they come together.”
Qualtrics’ own research shows that it can take just one negative experience to lose a customer, or an employee, and with the sheer array of tools available to businesses today, it is possible to continuously track and improve experiences. But possible doesn’t mean easy.
There’s plenty of data available – from user analytics to customer support chats to online sentiment analysis and everything in between. And while Qualtrics has all the software and AI capabilities to parse this information and make it not just digestible but actionable, Serafin said the secret sauce is something altogether more human.
“At the end of the day it comes down to this notion of empathy,” he said. And that’s the throughline of Serafin’s leadership, too.
In our interview, he expressed how empathy (and a helping of TACOS) is at the core of Qualtrics. He also shared what he learned about leadership from his early years on the family farm through to 17 years at Microsoft, where he faced a review with Bill Gates in his first week on the job.
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This week marks a truly important video game anniversary: it is 50 years since Nolan Bushnell and Ted Dabney incorporated Atari Inc, the company that laid the foundations for the video games industry. There have been many appraisals of the company and its landmark achievements in the games press over the past few days – from the arrival of a Pong machine in Andy Capp’s Tavern in Sunnyvale, California, in 1972, through classic titles such as Breakout, Asteroids and Missile Commands, to the iconic home consoles. So many moments of creative genius, so many genres, concepts and conventions bursting into existence at the hands of scruffy engineers and designers such as Ed Logg, Larry Kaplan and Dona Bailey.
But one element that often gets overlooked in these nostalgic reveries is the way in which Atari taught the first generation of electronic gamers how to think symbolically. With two rectangles and a square, Pong invited us to visualise tennis, while Night Driver’s series of moving rectangles convinced us we were driving a car. Some will point to the 1972 console the Magnavox Odyssey as the originator of these concepts, but it was Atari putting them in arcade machines – and later consoles –all over the world.
It was also Atari that generated a whole universe around its simple games. Through beautiful cabinet designs, expert use of iconography and graphic design, and the gorgeous illustrations on its Atari VCS cartridges, the company sought to simulate the imagination of players before they even held the controller. The boxes for titles such as Berzerk and Defender, all highly abstract and visually simple games, were alive with drama; they showed human characters, explosions and colours that were impossible to achieve on screen at the time, quietly providing players with the imaginative tools they needed to become immersed. Would we have cared so much about the fate of the lifeless rock at the base of the screen in Missile Command if it hadn’t been for George Opperman’s package art? The tense commander at his desk, the explosions, the missiles seemingly scorching out of the box itself …
It was George Opperman who also designed Atari’s now legendary logo, consisting of three simple lines, the two exterior shafts curving inwards toward the peak. Over the years Opperman claimed many influences for his design – Mount Fuji, Japanese alphabet symbols, Pong itself – personally, I’ve always viewed it as a spaceship. But it’s how the image seems to sum up the excitement and futuristic promise of the company that really matters. When we see the logo flash briefly on the screen in Ridley Scott’s Blade Runner, it’s a quick visual signifier that this is a highly technological landscape. It fits in perfectly with a world of androids and flying cars.
Nolan Bushnell saw how video games could naturally bleed from the screen into real space, meat space. During the 1970s, the industry started in pubs and taverns, then moved into arcades and eventually the home, and they had effects on all of them: they changed behaviours and got written into our lives in subtle ways. His introduction of the Chuck E Cheese pizza restaurant chain, which combined family eating with a video game arcade, brilliantly monetised the ways that games, although graphically simple, had worked their way from the TV screen to dinner table conversation. We laugh about how the original VCS console had wood panelling, but this was a deliberate attempt to ape the aesthetics of the 1970s living room, with its wooden furniture, TV and stereo cabinets. Atari understood that assimilation would be a vital element of success.
Even now, in this age of near photorealism, video games rely on the kind of abstractions that Atari perfected. The heart symbols to denote the number of lives we have left; the heavy use of icons and exterior narratives; the endless references to familiar cinema tropes. We saw Atari being played on TV shows and films, we saw Atari in comics. While its games were still being drawn with two sprites each a single byte in size, the iconography of Atari was out there in the world. It’s something Nintendo would learn from, and later Sony, with its cultural melting pot of a console: the PlayStation. Atari was a myth maker too: from the Easter egg hidden in Adventure to the buried copies of E.T. in the California desert, the company itself became a source of digital folklore that took on meanings beyond anything portrayed on your TV.
50 years ago, Atari began to show us that games exist in a strange liminal space between the screen and the brain, and they are constantly able to escape. The dots on the screen are only ever part of the picture, and the picture never stops moving.
What to play
While we’re in a nostalgic mood, I’m really enjoying Capcom Fighting Collection. You’d probably expect a dozen famous titles from the Street Fighter series, but that’s already been covered by Street Fighter 30th Anniversary Collection. Instead, we get five games from the spooky, goth-infused Darkstalkers series, the mid-1990s fantasy-themed Red Earth and a bunch of offbeat Street Fighter dalliances including the ridiculously compelling Super Puzzle Fighter II Turbo, which brilliantly combined fighting game dynamics with … Tetris. The games are filled with blistering attacks and truly imaginative character designs, all lovingly updated for the modern era.
Available on: PC, PS4, Switch, Xbox One Approximate playtime: As long as you want
What to read
Eurogamer is running a whole series of features for Pride, including this piece talking to Captain Fluke about being the first openly trans esports commentator and this one on the joy of gay fan faction and mods. Elsewhere, IGN has listed its favourite ever LGBT+ characters in video games.
Verge has a really interesting piece on a group of creatives making branded worlds for big companies in Fortnite. Everyone talks about Facebook when referencing the coming era of the metaverse, but I’m pretty sure Fortnite is going to be just as important as an explorable shared space for interconnected worlds – and the advertising potential therein.
We also found out this week that Hidetaka Miyazaki, the creative genius behind Dark Souls and Elden Ring, is almost finished on his next project. This is good news for me as, after 225 hours, I’m nearing the end of Elden Ring and would be very happy to slide straight into his next game if possible.
If I’ve got you interested in Atari’s design and illustration philosophy, The Art of Atari by Tim Lapetino is a gorgeous book. For a more technical analysis of the company, try Racing the Beam: The Atari Video Computer System by Nick Montfort and Ian Bogost.
This week’s question comes from Tim and his daughter Caitlin, and is answered by Keza:
“We got really into Hades over lockdown, loving the ‘it’s the same each time but really different too’ concept as well as the lore and the artwork. Can you recommend a similar game that we could play together?”
Hades is what’s known as a roguelike – one of those games where you have to start again from the beginning each time, but each playthrough throws different challenges at you – and, happily for you both, this genre has been having a moment over the past few years. Hades is a contender for the very best game in this genre, so it’s hard to rival, but here are some others to try.
Dead Cells is a kind of cyberpunk-fantasy action game where you gradually explore a shapeshifting castle; Spelunky 2 has you delving down below the Earth through caves full of amusing hazards, and has a great sense of humour (you can also play co-op); Into the Breach is something a little different, a strategy game where you have to defend the world from hostile invaders, travelling back in time after each failed attempt. And for a story and art style as good as that of Hades with a different gameplay feel, try developer Supergiant’s previous games Pyre,Transistor and Bastion, if you haven’t already.
China is claiming that as of Wednesday, its Tianwen-1 Mars orbiter has officially photographed the entire Red Planet. And it’s shown off new photos of the southern polar cap and a volcano to prove it.
“It has acquired the medium-resolution image data covering the whole globe of Mars, with all of its scientific payloads realizing a global survey,” state-sponsored media quoted the China National Space Administration (CNSA) announcing.
Among the images are one of Mount Askra with its crater, shots of the South Pole whose ice sheet is believed to consist of solid carbon dioxide and ice, the seven-kilometer deep Valles Marineris canyon, and the geomorphological characteristics of the rim of the Mund crater.
Mount Askela. Click to enlarge
Mars South Pole. Click to enlarge
Valles Marineris. Click to enlarge
Mund crater. Click to enlarge
Tianwen-1 had been in orbit around Mars for 706 days. The orbiter circled Mars 1,344 times, as of an announcement from CNSA. The space org said Tianwen-1 has completed its scheduled missions.
In conjunction with its rover Zhurong, Tianwen-1 amassed 1,040 gigabytes of raw scientific data through 13 onboard scientific payloads.
The mission has allowed CNSA to observe solar occultation and solar wind together with international observatories – including those in Russia, Germany, Italy, Australia and South Africa – to improve the accuracy of space weather forecasts. Good news for Matt Damon.
CNSA said it will share more scientific data with the international community in due course.
In December, Zhurong and the European Space Agency’s Mars Express spacecraft performed an in-orbit relay communication test to demonstrate it was possible to relay data from Zhurong back to Earth via Mars Express. The demonstration was successful, if a bit complicated – Mars Express had to “listen” for Zhurong since the rover was unable to communicate directly because the frequencies used don’t match.
Even though the mission is officially over, the orbiter and rover are still in working order. The orbiter will stay in orbit and continue its remote sensing and data relay activities while Zhurong will hibernate until weather conditions improve – likely in December. ®