Big Research on Tiny Things

Small Temperature Changes Have Glacial Consequences

Greenland’s coastline is dotted with glaciers that are separate from the island’s central ice sheet — and those glaciers are in a state of rapid retreat, according to a Northwestern and University of Copenhagen study. Led by Laura Larocca ’21 PhD, the research team compared current satellite images with historical aerial photographs of the coastline to track the changes in the lengths of more than 1,000 glaciers over the past 130 years. Although Greenland has experienced glacial retreat throughout the last century, the rate has accelerated over the past two decades, which have been marked by warmer summer air temperatures (up to 2 degrees Celsius warmer than the 1971–2000 baseline) and reduced snowfall. “Our activities over the next couple decades will greatly affect these glaciers. Every bit of temperature increase really matters,” says Larocca, who is an assistant professor at Arizona State University’s School of Ocean Futures. Learn more. 

In the Blink of a Star

An international team, including Northwestern astrophysicists, detected a new population of gravitational waves that are too big and change too slowly for current technologies to detect. As a workaround, researchers instead study pulsars, a type of rotating neutron star that spins rapidly, sending radio waves sweeping through space. “We see little flashes of light that tick like a clock,” says Caitlin Witt, a postdoctoral fellow at Northwestern’s Center for Interdisciplinary Exploration and Research in Astrophysics and at the Adler Planetarium. Using ground-based radio telescopes at Arecibo Observatory in Puerto Rico as well as in West Virginia and New Mexico, the researchers look for changes in the timing of the flashes. “If the clock ticks arrive a little early or a little late, this is a sign that [the flash of light] could have been affected by a [monstrous but elusive] gravitational wave,” Witt says. Nineteen of the pulsars that the North American Nanohertz Observatory for Gravitational Waves currently monitors were initially found with Arecibo. Learn more. 

Life in an Underwater Cave

The Yucatán Peninsula in southeastern Mexico is “a Swiss cheese of cave conduits,” says Magdalena Osburn, associate professor of Earth and planetary sciences. The region’s underwater cave system contains areas of freshwater, seawater and mixtures of both, in a variety of zones, including deep pits with no direct access to the surface and shallower sinkholes. Millions of people draw their drinking water from this cave system, says Osburn, “so whatever happens with the microbial communities there has the potential to be felt by humans.” With help from a cave-diving team led by Earth and planetary sciences professor Patricia Beddows, researchers constructed a map of the microbial communities to better understand what lives in these submerged labyrinths. Learn more. 

Taking Note of Inaudible Sounds

Suzan van der Lee deciphers Earth’s secret seismic language. Movements in Earth’s crust are inaudible, but van der Lee compresses seismic frequencies so they can be heard via Earthtunes, an app she codeveloped. For example, as seismic activity intensified ahead of a volcanic eruption in Iceland last fall, the region experienced hundreds of earthquakes per day. On Earthtunes, the activity sounded like a cacophony of doors slamming, hail pelting a tin roof and people cracking ice cube trays. The Sarah Rebecca Roland Professor of Earth and Planetary Sciences, van der Lee applies data science to millions of records of seismic waves to gather valuable insights about the Earth’s interior dynamics. Learn more. 

The Molecular Basis for Cancer

According to the World Health Organization, by 2040 more than 70% of cancer deaths are expected to occur in low- and middle-income countries. Research associate professor of preventive medicine Mamoudou Maiga studies the molecular mechanisms underlying diseases, with an emphasis on infectious diseases and cancers. He identifies molecular indicators that are crucial for signaling the presence or progression of cancer. Maiga, director of translational research at Northwestern’s Center for Innovation in Global Health Technologies, seeks to improve public health outcomes in the developing world, where the majority of cancer cases are detected at late stages, leaving limited treatment options. For nearly two decades, he has focused on the development of preventive strategies and diagnostic tools in West Africa, including in his home country, Mali.