Quanta Physics World  January 2018

Seen and heard

Weird and wonderful stories from the world of physics

(ICRR)

Watery world

If you want a challenge for the new year, the Institute for Cosmic Ray Research (ICRR) in Tokyo, Japan, has just the thing. It’s created a 300-piece jigsaw of the Super-Kamiokande neutrino detector in Kamioka, Japan. The detector is a giant stainless-steel tank filled with 50,000 tonnes of ultra-pure water and lined with 13,000 photomultiplier tubes that detect the Cherenkov radiation released when a neutrino collides with a water molecule. In other words, it’s a jigsaw puzzle featuring water and lots and lots of identical tubes. Costing ¥1500 (£10) and with a finished size of 38 × 26 cm, a limited number of the jigsaws went on sale in late October. But its fiendish nature doesn’t seem to have put anyone off: the puzzle sold out within days. Jigsaw enthusiasts, however, will be pleased to know that, as Physics World went to press, the ICRR was planning to release more.

Once and once again

This magazine’s “once a physicist” column has for many years profiled people who have gone on to do something else, such as Elon Musk, who founded PayPal and Space X. But we recently spotted someone who’s a “once-and-now-again-a-physicist”. Sandra Miarecki did a bachelor’s degree in astronomy at the University of Illinois Urbana–Champaign, graduating in 1986 before becoming a US Air Force pilot for 20 years. In 2010 she then came back full circle and began a PhD in neutrino physics at Lawrence Berkeley National Laboratory, which she completed in 2016. “I debated whether my 42-year-old brain would be spongy enough to tackle a PhD programme,” Miarecki told Symmetry. She’s now an assistant professor at the Air Force Academy in Colorado Springs, teaching classical mechanics and electromagnetism. Maybe that actually makes her a “once-a-once-and-now-again-a-physicist”.

Anchovies in space

Italian astronaut Paolo Nespoli seems to have been having a fun time on the International Space Station (ISS). In November he became the first person to contribute to Wikipedia from space when he recorded and uploaded two audio messages, one in English and one in Italian. In the 44-second clip, Nespoli outlines the three times he travelled into space, the first being in 2007 when he was on the Discovery shuttle that helped to build the ISS. Shortly after his Wikipedia exploits, Nespoli and his five colleagues on the ISS then spent time painstakingly crafting their own pizzas using ingredients in a kit delivered on a cargo resupply mission that contained flatbread, tomato sauce, cheese, pepperoni, olives, olive oil, anchovy paste and pesto. After playing around with the pizzas like they were frisbees, the astronauts cooked them in foil. Nespoli, who has been in orbit since July, declared them “unexpectedly delicious”. It must be the furthest fast-food delivery in history.

 

(S Rubinstein / Harvard University)

Feeling crumpled?

The end of the holiday season can mean a lot of recycling. And as we all know, if you put a dent into the side of an aluminium can, it’s easier to crush from top to bottom. But predicting the exact force needed to crumple a dented can is notoriously difficult, requiring knowledge of the exact dimensions and position of the flaw. Thankfully, physicists at the École Polytechnique Federale de Lausanne and Harvard University have now worked out a relationship between the size of the dent and the force needed to buckle the can (Phy. Rev. Lett. 119 224101). They put an empty Coke can in between two metal plates to produce a vertical force. The researchers then poked the side of the can using a metal ball attached to the end of a rod, continuously pushing the ball further into the can until it buckled with a loud snap. By varying the size of the ball and the force of the plates, they determined that the cans generally buckle with a force greater than 700 N. The researchers say that the work could help with the design of rockets, aeroplanes and, of course, beer cans.