Category: Front page block widget (4 posts)

Just Like Chocolate

Recycling plastics for a greener future By: Molly Sun Every day, I cook up something new – fresh biscuits, fettuccine, and even soft-serve ice cream. But none of my creations are edible. The fluffy biscuits are buttery-yellow polyurethane foam, deceptively warm and soft. The fettuccine noodles are long, brittle strands of polyurethane film with a snap as satisfying as their alfredo-smothered twins. As a polymer chemist, I make and study polyurethane in all their weirdly delicious forms to figure out not how to eat them (to my regret on dinnerless late nights in the lab), but how to consume them as recyclable plastics. As they are, none of my plastic creations are recyclable either – a deep problem for a hungry world saturated with plastic waste. While consuming our leftovers presents an appetizing solution, the puzzle lies in how to make our used polyurethanes palatable again. Most plastics fall in a category called thermoplastics, meaning heat breaks down their molecular structure and makes them easy to reshape, like chocolate. For example, the polyethylene that makes up water bottles is a thermoplastic, so like chocolate, they are easy to melt down and mold into new shapes. The tiny molecular chains in thermoplastics are held together merely by weak electrostatic attractions, like strands of yarn bound to each other by a shock of winter static. However, most polyurethane has a particular chemical structure that prevents it from being remolded like thermoplastics. Its molecular strings are locked together by chains known as crosslinks, as if strands of soft, pliable yarn were linked by metal chain links. The presence of crosslinks dramatically changes the properties of […]

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Vicky Kalogera is Thrilled by the Extraordinary

A senior astrophysicist at the LIGO Scientific Collaboration and Daniel I. Linzer Distinguished University Professor at Northwestern, Kalogera digs into why she keeps coming back to astrophysics, after more than three decades in astronomy. By: Katie Liu The universe chirped on a Monday. The first indication that astronomical history had been made came in the form of emails piling in Dr. Vicky Kalogera’s inbox. Kalogera, a professor of physics and astronomy at Northwestern, was also a leading astrophysicist of an international group of scientists known as the Laser Interferometer Gravitational Wave Observatory (LIGO) Scientific Collaboration. They were chasing after an elusive aftereffect of colliding black holes and dead stars, known as gravitational waves. Albert Einstein predicted their existence over a century ago, but such phenomena were long thought impossible to detect. It was September 14, 2015. LIGO detectors had just turned on following several years of instrument upgrades and renovations. That Monday was also packed for Kalogera, as she juggled hours of back-to-back meetings. Communication zipped back and forth as she checked her phone every now and then. There was something about a signal. Kalogera was convinced, however, it had to be yet another system test – extra insurance to check that the detectors were working properly. With that in mind, she went on to pick up her then-three-year-old from daycare and headed home. As she was setting up dinner, one of her graduate students pinged her with a text. “Have you looked at our emails today?” Yes, Kalogera replied, she had. “Are we testing? Is this a signal? What are we doing?” “We got a signal.” No way, she […]

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Fungus Eating Flowers: Orchids, Climate Change, and the Nature of Evolution

By: Christian Elliott A shorter version of this story ran in Sierra Magazine on December 4, 2022. Dennis Whigham closes the car door, straightens his blue baseball cap and squints into the woodland before him. A maze of planks crisscrosses a forest floor covered with cables and hoses. Little yellow flags wave in the breeze and lights on white metal boxes tied to trees blink on and off. Motors hum as little robot lids open and close, taking methane measurements. PVC pipes support wide nets of leaves above the ground. He smiles. “Now all I have to do is figure out where the hell we put the seed packets,” he says, stroking his white beard.  This is the Smithsonian Environmental Research Center’s high-tech experimental forest in coastal Maryland. Twice a year, scientists flood it with 80,000 gallons of saltwater to study the effects of hurricanes and sea level rise on forests. It’s a massive, expensive undertaking called TEMPEST. But Whigham’s goal here is different. He, like many other Smithsonian scientists, has hitched a ride on TEMPEST’s infrastructure – International Space Station-style – to do his own experiment. He wants to know how sea level rise will affect Maryland’s native orchids. He’s arrived with his longtime colleague Melissa McCormick to locate and dig up orchid seeds they planted throughout the forest a year ago to see if any have sprouted. It’s not an easy task, but two heads are better than one. As she walks carefully through the dead leaves, trying not to step on hoses, McCormick points out a small green leaf, speckled with purple.  “Tipularia!” she says triumphantly, bending […]

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