Quanta Physics World  May 2018

Seen and heard

Weird and wonderful stories from the world of physics

(Cardiff University)

The price of football

With the 2018 FIFA World Cup kicking off next month, you’d better start collecting those Panini stickers now if you want a compete album. There are 682 stickers this time, but how much would it cost to collect them all? There are five stickers in a packet, which each costs 80p, so if you were incredibly lucky and had no duplicates it would take 137 packets, or £109.60, to complete. In reality, you will end up with lots to spare – probably of an obscure Panamanian right back – so Cardiff University mathematician Paul Harper has analysed the realistic cost of finishing the album. He found that, if you just bought packet after packet without swapping duplicates with friends, you would need to buy, on average, 4832 stickers or 967 packets to complete the book, at a whopping £773.60. But if you got together 10 friends in a swap group, filling the album would reduce the cost to a mere £247. Bargain.

The rhythm of the beat

Are music fans’ movements during a rock concert the same as those of fans during a football match? To answer that question, in 2016 seismologist Jordi Díaz from the Institute of Earth Sciences Jaume Almera in Barcelona installed a seismometer in the basement of the institute’s building, which is near to FC Barcelona’s stadium. Speaking at the European Geosciences Union general assembly in Vienna last month, Díaz revealed that he could pick up signals from football fans jumping up and down when their team scored – and even as they entered and left the ground. A rather large signal came in March 2017 when Barcelona were playing Paris Saint-Germain in a Champions League knock-out game. Trailing 4-1 from the first leg, Barcelona scored in the final minute of the match to win 6-5, taking them through to the next round and sparking wild celebrations. Díaz also studied the signal generated from a Bruce Springsteen rock concert in the city in 2016, finding that the seismometer could even be used to differentiate songs because fans danced differently depending on the rhythm of a tune. And as the music fans’ movements are more coordinated than those of the football fans, the seismometer could also differentiate between the two forms of activity. Yes, but what happens when football fans start dancing?

Fake news

Mathematical physicists Alexandre Bovet of Belgium’s University of Namur and Hernan Makse of the City College of New York have looked at how Twitter users interacted with purveyors of fake news during the 2016 US presidential elections. Using a “comprehensive” dataset of 171 million Tweets made during the five months before the election, they identified 30 million Tweets, sent by 2.2 million users, which were classified as spreading fake and extremely biased news. They found that “influencers” who spread centre- and left-leaning news largely determined the opinion of Hillary Clinton supporters. Yet they found the opposite for right-wing voters, who tended to influence the output of people producing fake-news Tweets. And who, according to the study, was one of the biggest spreaders of biased news? Yes, @realDonaldTrump.

 

(iStock / CopterAnansak)

Subatomic vote

What’s your favourite particle? Physics labs around the world were championing their favourites in March for the title of “Most Awesome Subatomic Particle”. CERN backed the proton with the SLAC National Accelerator Laboratory in California putting its weight behind the photon. The electron, meanwhile, was championed by the National High Magnetic Field Laboratory in Tallahassee, Florida, while the Institute for Quantum Matter at Johns Hopkins University in Baltimore, Maryland, supported the neutron. After some intense canvassing, in late March people took to Twitter to pick their favourite. The winner, with 36% of the vote, was the photon. Second was the proton with 26%. The electron came third with 22% followed by the neutron with a lowly 16%. One wonders why the neutrino was left out; after all, it could be the only particle to offer physics beyond the Standard Model.