Science

Ashokan Reservoir, October 2024. Photo: Agnes Laylicha, School of International and Public Affairs and Columbia Climate School Increasing climate variability is threatening the water supply and exposing the fragility of the New York City watershed, which hosts the largest unfiltered water supply in the world. Columbia Climate School students had the opportunity to learn about the history of this critical reservoir system—one that supplies 10 million New Yorkers with over 1 billion gallons of safe drinking water every day—on a recent field trip. The New York City Watershed: From Community Displacement to Collaboration and Climate Adaptation, one of four practicum courses offered annually within the sustainable development program, takes students to the Catskill Mountains to learn fir...

Shutterstock/Dr. Norbert Lange This story is part of our Cosmic Perspective series, in which we confront the staggering vastness of the cosmos and our place in it. Read the rest of the series here. We think our universe contains everything that exists, has ever existed and will exist in the future. But this might not be the case: there are many ways other universes could exist. One is that we could be a single part of a branch of infinite universes known collectively as the multiverse. These universes might have appeared shortly after the big bang, they might be hiding in extra dimensions or they could pop into existence whenever a quantum property goes from a cloud of possible states to a single reality. Multiverse ideas gained scientific weight in the 1980s with...

Glaciers have historically determined the boundary between Italy and Switzerland in the Alps. Now, their melting has led the two countries to redraw a small section of their border over the past year and revived concerns of how climate change might impact mountain communities around the world in the coming years. Glaciers form the borders of many countries—ranging from those in the Andes that separate Chile from Argentina to the Siachen Glacier, which marks the northern point of the Line of Control in the disputed Kashmir region between India and Pakistan. Glaciers in the Alps define the borders between Italy and a number of countries, including Switzerland and Austria. However, climate change is leading global temperatures to rise, and high-mountain areas are warming even more rapi...

Tattoos printed onto a person’s scalp can detect electrical activity in the brain and carry signals to a recording deviceNanshu Lu Analysing brainwaves could be made easier by printing a temporary tattoo onto a person’s head. Electroencephalography (EEG) is a way of measuring electrical activity in the brain via electrodes placed on the scalp. It can be used to test patients for neurological conditions such as epilepsy, tumours or injury from stroke or traumatic impacts to the head. Because people’s skulls vary in size and shape, technicians have to spend considerable amounts of time measuring and marking the scalp to get accurate readings. A gel helps the electrodes detect brain signals, but it stops working well as it dries. The cables that connect to the electr...

Most of us don’t think much about electric charge, apart from in those annoying moments when our phones run out of it. But for physicists, it is a big deal. In every atom, negatively charged electrons orbit a nucleus containing positively charged protons, with the whole dance sustained by their mutual attraction. It would be fair to say, then, that charge is about as fundamental as it gets. This explains why physicists have long been at such pains to understand its nature, and for the most part they have been successful. But there is one question that has always hung in the air, unanswered. It seems that the smallest possible unit of charge is that of an electron – all other naturally occurring particles only have multiples of this. In nature, you can find charges of ...