Scientists have unveiled a striking radar image from the U.S.-India Earth-observing NISAR satellite that resembles a hummingbird emerging from Antarctica’s icy landscape. The image, created using the satellite’s advanced L-band radar, showcases Nunatak Zaterjavshijsja, a mountain peak protruding through East Antarctica’s vast ice sheet while revealing intricate fractures in the surrounding glacier.
The image, produced in August 2025 and released by NASA, has been nicknamed “the hummingbird” by NISAR scientists because of its distinctive shape. Beyond its visual appeal, the radar image offers valuable insights into glacier dynamics and the structural changes occurring deep within Antarctica’s ice.
Mountain Peak Creates Dramatic Ice Fractures
Nunatak Zaterjavshijsja sits in East Antarctica, where a massive stream of ice flows northeast toward the ocean. As the glacier moves around the exposed mountain, enormous stress builds up within the ice, creating extensive cracks known as crevasses.
These deep fractures appear as bright green streaks in the radar image, highlighting areas where the ice surface has become heavily fractured due to the obstruction caused by the mountain.
The radar imagery enables scientists to study these hidden ice structures with remarkable precision, even in regions that are difficult to access on the ground.
How NISAR Created the Colourful Image
Unlike traditional optical satellites that rely on sunlight, NISAR uses Synthetic Aperture Radar (SAR), allowing it to capture detailed images regardless of cloud cover or darkness.
For this image, the satellite’s L-band radar transmitted horizontally polarised microwave signals toward Earth’s surface. The colours represent how those signals bounced back after interacting with different types of ice.
- Magenta indicates smoother, more regular ice surfaces where radar signals reflected back with horizontal polarisation.
- Green highlights areas where radar waves penetrated the ice or scattered off rough, fractured surfaces such as crevasses, a process known as volume scattering.
- White marks locations where both surface and volume scattering occurred strongly, suggesting a combination of smooth and fractured ice.
This colour-coding allows researchers to distinguish between stable ice and heavily stressed regions.
Why the Image Matters
Although visually impressive, the radar image serves a much larger scientific purpose.
Monitoring crevasses and glacier movement helps scientists understand how Antarctic ice sheets are changing over time. Such observations are essential for studying ice flow, glacier stability and future contributions to global sea-level rise.
Because radar can penetrate clouds and operate day and night, NISAR will provide continuous observations of Earth’s changing landscapes throughout its mission.
About the NISAR Mission
NISAR (NASA-ISRO Synthetic Aperture Radar) is a joint mission between NASA and the Indian Space Research Organisation (ISRO), making it one of the most ambitious Earth-observation collaborations between the two space agencies.
The spacecraft carries two radar systems operating at different wavelengths:
- NASA supplied the L-band Synthetic Aperture Radar and the massive radar reflector.
- ISRO developed the spacecraft bus and the S-band Synthetic Aperture Radar.
The satellite also features a 39-foot (12-metre) drum-shaped antenna reflector, the largest radar antenna reflector NASA has ever launched into space.
By combining observations from both radar frequencies, NISAR is expected to transform scientists’ understanding of glaciers, forests, earthquakes, wetlands, agriculture and other rapidly changing features of Earth’s surface.