NOAA-21 Archives

The final accumulated nighttime light change area: A night-time view of Earth, capturing human activity across the eastern hemisphere of the planet through the emissions of artificial light. Derived from satellite images taken daily over the past decade, the image maps the dynamics of the human night-time activity, with golden areas experiencing brightening, purple areas featuring dimming, and white areas experiencing both. Credit © Michala Garrison/NASA Earth Observatory

Astronomy & Telescopes, Imaging & Spectroscopy, Press Release, SETI & Technosignatures

Terrestrial Technosignatures: Satellites Capture The Glowing Pulse Of Human Civilization

by Keith CowingApril 10, 2026April 10, 2026

An analysis of data from the VIIRS DNB satellite instrument covering the years 2014 to 2022 finds that nighttime lighting is increasing globally by about two percent per year. “Although […]

The VIIRS on NOAA-21 captured this cloud-free image of a phytoplankton bloom on 9 August 2024. -- NASA

Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Imaging & Spectroscopy, Microbiology & Virology, Status Report, Water/Hycean Worlds & Oceanography

Orbital Biosignature Survey: A Bright Blue Coccolithophore Bloom In The Barents Sea

by Keith CowingAugust 14, 2024August 14, 2024

When summer arrives at high northern latitudes, peripheral seas to the Arctic Ocean lose some of their ice cover and bask in long daylight hours. That’s when phytoplankton—microscopic plant-like organisms […]