Articles

A satellite image of a cavum.

Cavum: Hole-punch Clouds

Caitlin Dempsey

Cavums are also known as hole-punch clouds or fallstreak holes.

A black and a brown cow in a grassy pasture.

Mapping Methane: the Launch of MethaneSAT and the Limitations of Satellite Data

Caitlin Dempsey

While advances in remote sensing and satellite technology have improved methane mapping, ground measurements remain essential for accurate, localized data.

Map showing areas of increased artificial lighting in the Arctic, with increases in yellow, decreases in purple, and no change in green, using data from the U.S. DMSP satellites. Map: NASA, public domain.

Increased Light Pollution in the Arctic

Caitlin Dempsey

Satellite data shows rising Arctic nighttime lights, driven by growing industrial activity in oil, gas, and infrastructure.

This 2024 Landsat 8 image shows Yakutat, Alsek, and Grand Plateau Glaciers have retreated up to 7.8 kilometers (4.8 miles), with lakes filling the void. Over 40 years, the lakes more than doubled in size to 240 square kilometers—larger than New York’s Seneca Lake.

The Rise of Proglacial Lakes

Caitlin Dempsey

Glacial retreat in Alaska's Yakutat Foreland has fueled rapid growth of proglacial lakes, doubling their size in 40 years as seen in Landsat imagery.

Earthrise over the Moon: partly-illuminated Earth rising over the lunar horizon. In this photo, the Earth is about 400,000 miles away. Photo: Apollo 11, AS11-44-6552, July 20, 1969.

Overview Effect: Quotes from Astronauts After Seeing the Earth from Space

Caitlin Dempsey

The Overview Effect is a shift in awareness by astronauts seeing Earth from outer space as a “tiny, fragile ball of life.”