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Backgrounders are informational articles providing a deeper explanation of key topics in Earth science to aid in understanding data and data use.

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Nighttime lights data over the Indus River Valley

Nighttime Lights
Remote sensing of nighttime light emissions offers a unique perspective to monitor human behaviors, such as electrification of remote areas, disaster recovery, and more. (May 2021)

All Backgrounders

What is Data Latency?
Several factors affect the speed at which data are processed and made available to users. Here's how NASA's Earth Observing System Data and Information System (EOSDIS) defines data latency. (August 2020)

logo of the United Nations Sustainable Development Goals

Sustainable Development Goals
Sustainable Development Goals (SDGs) serve as an aspiration, what United Nations member countries hope to ideally achieve in the future. Earth observations can be used in monitoring progress towards reaching each goal. (June 2020)

What is Synthetic Aperture Radar (SAR)?
Learn more about SAR, a type of active data collection where a sensor produces its own energy and then records the amount of that energy reflected back after interacting with the Earth. (April 2020)

Essential Variables
Essential variables are variables known to be critical for observing and monitoring a given facet of the Earth system. Learn how they ensure the usability of data across multiple platforms and agencies. (March 2020)

What is Remote Sensing?
Remote sensing is the acquiring of information from a distance. Read about how remote sensors enable data-informed decision-making based on the current and future state of our planet. (September 2019)

Diagram of a passive sensor versus an active sensor.

Diagram of a passive sensor versus an active sensor. Credit: NASA Applied Remote Sensing Training Program

Remote Sensors
Learn about the difference between active and passive remote sensing instruments.

Geographic Information Systems (GIS)
GIS is a collection of computer-based tools for organizing information from a variety of data sources to map and examine changes on Earth.

Published November 5, 2020

Page Last Updated: May 19, 2021 at 12:18 PM EDT