Science

Researcher used a laser to superheat a sample of gold and measured its temperature with a pulse of ultra-bright X-raysGreg Stewart/SLAC National Accelerator Laboratory Wafer-thin sheets of gold shot briefly with lasers can be heated up to 14 times their melting point while remaining solid, far beyond the theoretical limit, raising the possibility that some solids may have no upper melting point at all. Superheating is a common phenomenon where a solid can heat up beyond its melting point, or a liquid can heat up past its boiling point, without changing state. For example, a cup of water heated in a microwave can reach temperatures above 100°C (212°F), as long as the cup is sufficiently smooth and still. However, as soon as the cup is jostled, the water will violently b...

Tiffany Wu, a 2023 graduate of Columbia University’s MPA in Environmental Science and Policy program, is a senior program associate at Winrock International, which provides solutions to complex social and agricultural challenges worldwide. Wu works on climate and sustainability projects spanning carbon markets, corporate greenhouse gas accounting and clean energy. Courtesy of Tiffany Wu Drawing on her diverse experiences in field research, as well as her background in corporate and nonprofit roles, Wu bridges science, policy and strategy to help organizations take meaningful climate action. In the Q&A below, Wu speaks about her career path, the lessons she learned at Columbia and her advice for students entering the field. Can you tell us about your current work? I’m a seni...

Did the cosmos arise out of a big bounce from another universe?Vadim Sadovski/Shutterstock Could our universe be expanding and shrinking back into a tiny point, reliving a kind of big bang over and over again? Probably not, according to a mathematical analysis that argues that the laws of physic forbid such a cyclic universe. A key moment in the life of a cyclic universe is the big bounce, an alternative to the big bang as the beginning of the known universe. The big bang starts with a singularity – matter and energy packed into a point so dense that gravity becomes strong enough to elude the laws of physics as we understand them – followed by an endless outwards expansion. But if the universe began with a big bounce, we could look beyond what we think of as the b...

Adapted from a release written by Alison Auld for Dalhousie University Lamont’s R/V Marcus G. Langseth. Credit: Anne Becel A new study published in Science Advances has revealed the first detailed images of a newly developing subduction zone off the coast of British Columbia’s Haida Gwaii archipelago. The international team of researchers collected the data for this study during a 2021 cruise by the Lamont-Doherty Earth Observatory’s research vessel, the Marcus G. Langseth. They used a 15-kilometer-long underwater cable equipped with thousands of underwater microphones, called hydrophones, in the area off northern British Columbia to map the deep structure of the Earth’s subsurface. Their data confirmed that the Queen Charlotte fault system can generate powerful megathrust eart...

In the past two decades, the US President’s Emergency Plan for AIDS Relief (PEPFAR) has prevented millions of deaths and new HIV infections through the provision and support of HIV testing, treatment, and prevention programs in more than 50 countries worldwide (1). Although HIV remains incurable, treatment with antiretroviral therapy (ART) leads to sustained viral suppression, which halts both immune system destruction and HIV transmission (2–4). With ART delivery at its core, PEPFAR has been enormously successful in improving both individual and public health: At the end of 2024, more than 20 million people were receiving life-saving ART through PEPFAR, and between 2010 and 2023, new HIV infections were reduced by an estimated 52% in PEPFAR-supported countries (1). However, in January, th...