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Geolens

Glossary

417 words used in the labs.

Find a term from the labs, understand the process behind it, and see how it appears in the landscape. Each entry connects an explanation with a real observation and a model you can explore.

Term

Syzygy

An approximately straight-line alignment of three celestial bodies. In the Sun–Earth–Moon system it occurs around new and full Moon and contributes to spring tides. An eclipse also requires sufficiently close alignment with the relevant orbital node and shadow.

What to look for

NASA's airborne view of the 21 August 2017 total solar eclipse. The Moon blocks the bright photosphere, revealing the corona.

Related labs

Tides →
The dark lunar disc surrounded by the Sun's pale corona during the 2017 total solar eclipse.
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Explore further with USGS water glossary · USGS volcano glossary · NPS glacial geology · NASA Earth facts. Photograph acknowledgements are collected on the Image credits page.